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Lymphocyte Proliferation (lymphocyte + proliferation)
Selected AbstractsMicrocystin-LR modulates selected immune parameters and induces necrosis/apoptosis of carp leucocytes,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2010Anna Rymuszka Abstract Microcystins (MCs) are potent hepatotoxins acting by the inhibition of protein phosphatase 1 and 2A, and may promote liver tumors. Moreover, studies also suggest they are nephrotoxic. The aim of the present study was to assess possible in vitro effects of microcystin-LR (which contains the amino acids leucine and arginine, the most widely studied and distributed variant of all microcystins) on the selected immune functions of the cells isolated from the head kidney of carp. In the experiments, pure microcystin-LR (MC-LR), was used at concentrations of 0.01, 0.1, 0.5, and 1,µg/ml RPMI-1640 medium. Leucocytes (lymphocytes and phagocytes) were isolated by centrifugation on a density gradient. Lymphocyte proliferation, intracellular production of reactive oxygen species by phagocytes, and the presence of apoptotic and/or necrotic cells were assessed. The respiratory burst activity of phagocytic cells was increased at the lowest toxin concentration used in the study, but it was decreased at higher concentrations. Using a sensitive luminescent immunoassay, MC-LR was observed to have no influence on the T-cell proliferation but decreased the proliferation of B lymphocytes. Moreover, it was noted that MC-LR induced necrosis to a higher degree than apoptosis in fish leucocytes. The results of the present study suggest the modulatory potency of microcystin-LR on fish leucocytes. Environ. Toxicol. Chem. 2010;29:569,574. © 2009 SETAC [source] Allergenicity testing of supermethrin, phenoxyacetic acid and DNCB using in vivo and in vitro modifications of the local lymph node assays, maximization and epicutaneous testingJOURNAL OF APPLIED TOXICOLOGY, Issue 4 2001M. Kuricova Abstract The purpose of this study was to compare two methods of testing for allergenicity: in vivo and in vitro modifications of local lymph node assays (LLNA) in mice and the maximization and epicutaneous skin tests in guinea pigs as per the Organization for Economic Cooperation and Development (1981). Two pesticides,the synthetic pyrethroid insecticide supermethrin (SM) and the herbicide phenoxyacetic acid (PAA),were evaluated using this testing battery. 1-Chloro-2,4-dinitrobenzene (DNCB) was selected as a reference allergen for the local lymph node assay. In vitro modification of LLNA proliferative response per standard cell count in lymphocyte cultures derived from treated Balb/c mice did not differ from control mice. Results of the in vivo modification showed that treatment with 50% PAA and 50% SM resulted in a lower proliferation response of lymphocytes in lymph nodes compared with control animals. The vigour of the proliferative response varied more in in vivo modification of LLNA. Stimulation indices were <3, so PAA and SM did not indicate classification as allergens. Lymphocyte proliferation in 1% DNCB-activated lymph nodes was approximately fivefold higher than in those derived from control mice. Proliferation response in vitro calculated as stimulation index was higher in DNCB-treated mice than those observed in vivo, but differences were not dramatic. Auricular lymph node weight and cellularity in mice treated with PAA and SM were similar to controls. The DNCB stimulation index for lymph node cellularity was 5.5. Lymph node weight was three times higher in comparison with controls. In the maximization test in guinea pigs SM and PAA acid resulted in 40% and 50% of animals demonstrating sensitization, respectively. Epicutaneous administration resulted in weaker reaction. Both SM and PAA are mildly strong sensitizers by this battery. Copyright © 2001 John Wiley & Sons, Ltd. [source] Comparison of ATP production in whole blood and lymphocyte proliferation in response to phytohemagglutininJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 5 2007Nancy H. Augustine Abstract Lymphocyte proliferation in response to mitogens, phytohemagglutinin (PHA), concanavalin A, pokeweed, and/or specific antigens has been the method of choice for in vitro diagnosis of cell-mediated immune dysfunction. Recently, an assay to measure intracellular adenosine triphosphate (ATP) production in response to PHA has been developed that requires a shorter, overnight incubation. We compared a standard 5- to 7-day lymphocyte mitogen stimulation assay utilizing tritiated thymidine (3H-thy) incorporation to one in which ATP production in response to PHA by CD4-positive cells is measured in a luminometer that requires only 18,24,hr. A total of 20 patient samples suspected of having decreased cell-mediated immunity submitted for mitogen induced lymphocyte proliferation and 21 normal controls were tested in both assays. A comparison of these two methods has demonstrated that the screening ATP assay has a sensitivity at 24,hr of 100% in detecting decreased PHA induced lymphocyte proliferation at 5 days and a specificity of 85% in the samples obtained from normal controls. The data indicate that the ATP assay may be a useful screening tool for more rapid detection of blood samples with decreased cell-mediated immune responses. However, a positive screen should always be confirmed by 3H-thy uptake using mitogens and recall antigens like candida and tetanus. J. Clin. Lab. Anal. 21:265,270, 2007. © 2007 Wiley-Liss, Inc. [source] Cutaneous marginal zone B-cell lymphoma in the setting of fluoxetine therapy: a hypothesis regarding pathogenesis based on in vitro suppression of T-cell-proliferative responseJOURNAL OF CUTANEOUS PATHOLOGY, Issue 7 2006Thomas S. Breza Jr Introduction:, Drugs may be an important cause of atypical lymphocytic infiltration. Oftentimes, these infiltrates are in the context of pseudolymphomata. We report a patient who developed lymphocytoma cutis temporally associated with initiation of fluoxetine therapy that later went on to develop cutaneous marginal zone B-cell lymphoma. The response of peripheral blood lymphocytes to fluoxetine and other drugs was examined in an attempt to ascertain the potential role for drugs in the propagation of these infiltrates. Materials and Methods:, Routine light microscopic analysis and phenotypic studies were performed on tissue obtained from a skin biopsy. Lymphocyte mitogenic studies were carried out using increasing concentrations of fluoxetine, bupropion, and two anticonvulsants. Results:, An initial biopsy was consistent with lymphocytoma cutis. The patient stopped fluoxetine associated with lesional regression. The lesions recurred despite being off fluoxetine; a repeat biopsy was compatible with marginal zone lymphoma. Lymphocyte proliferation assays revealed a suppressive effect on T-lymphocyte proliferation at physiologic concentrations. Other tested drugs did not have a similar suppressive effect. Conclusion:, Fluoxetine may be associated with pseudolymphomata and marginal zone lymphoma. The inhibitory effects on T-lymphocyte function and more specifically T-suppressor function may lead to excessive antigen-driven B-cell proliferation. [source] Immunotherapy with live BCG plus heat killed Leishmania induces a T helper 1-like response in American cutaneous leishmaniasis patientsPARASITE IMMUNOLOGY, Issue 2 2000Maira Cabrera Previous work has shown that American cutaneous leishmaniasis (ACL) patients treated with viable BCG plus heat killed promastigotes of Leishmania amazonensis show the same rate of cure as patients receiving conventional chemotherapy. The treatment is safe and economical, but the immunological correlates of cure have not been examined. In the present study, T cell responses have been analysed in 43 ACL patients, including patient groups sampled before and after therapy, and in 10 endemic controls. Lymphocyte proliferation, interferon (IFN)-, and interleukin (IL)-5 responses to crude antigen (L. amazonensis, MEL; Mycobacterium tuberculosis PPD; M. bovis BCG) stimulation, and serum IL-5 levels, were analysed. In endemic volunteers, proliferative responses to BCG were high and IFN-, responses low. In contrast, localized cutaneous (LCL) and mucocutaneous (MCL) patients showed low proliferative and high IFN-, responses to BCG. Treatment enhanced the IFN-, response and further decreased the proliferative response to BCG, especially in MCL patients. LCL and MCL patients showed an increase in proliferative and IFN-, responses to MEL with treatment, but the response was not exaggerated in MCL patients, either before or after treatment, compared to LCL patients. IL-5 production was low in T cell assays, and > 62% of untreated patients had very low serum IL-5 levels. There were no significant changes in serum IL-5 with treatment. Overall results show enhanced antigen-specific IFN-, responses to the two components of the immunotherapy, live M. bovis BCG and heat killed L. amazonensis, which is consistent with a shift in balance of T cell response towards a T helper 1 response and clinical cure mediated by IFN-,. [source] PAN,DR-Binding Hsp60 self epitopes induce an interleukin-10,mediated immune response in rheumatoid arthritisARTHRITIS & RHEUMATISM, Issue 7 2009Huib de Jong Objective Human Hsp60 is expressed in the joints of patients with rheumatoid arthritis (RA) and can elicit a regulatory T cell response in the peripheral blood and synovial fluid. However, Hsp60 can also trigger strong proinflammatory pathways. Thus, to understand the nature of these Hsp60-directed responses in RA, it is necessary to study such responses at the molecular, epitope-specific level. This study was undertaken to characterize the disease specificity and function of pan,DR-binding Hsp60,derived epitopes as possible modulators of autoimmune inflammation in RA. Methods Lymphocyte proliferation assays (using 3H-thymidine incorporation and carboxyfluorescein diacetate succinimidyl ester [CFSE] staining) and measurement of cytokine production (using multiplex immunoassay and intracellular staining) were performed after in vitro activation of peripheral blood mononuclear cells from patients with RA, compared with healthy controls. Results A disease (RA),specific immune recognition, characterized by T cell proliferation as well as increased production of tumor necrosis factor , (TNF,), interleukin-1, (IL-1,), and IL-10, was found for 3 of the 8 selected peptides in patients with RA as compared with healthy controls (P < 0.05). Intracellular cytokine staining and CFSE labeling showed that CD4+ T cells were the subset primarily responsible for both the T cell proliferation and the cytokine production in RA. Interestingly, the human peptides had a remarkably different phenotype, with a 5,10-fold higher IL-10:TNF, ratio, compared with that of the microbial peptides. Conclusion These results suggest a disease-specific immune-modulatory role of epitope-specific T cells in the inflammatory processes of RA. Therefore, these pan,DR-binding epitopes could be used as a tool to study the autoreactive T cell response in RA and might be suitable candidates for use in immunotherapy. [source] Immunoprophylactic evaluation of a 37-kDa Brugia malayi recombinant antigen in lymphatic filariasisCLINICAL MICROBIOLOGY AND INFECTION, Issue 4 2006P. Dabir Abstract The Brugia malayi filarial antigens recognised preferentially by sera from an endemic normal population are considered to be potential vaccine candidates. By immunoscreening the cDNA library of the infective L3 stage of B. malayi with pooled endemic normal sera, a cDNA clone Bm-SL3 was identified. Analysis of sera from different patient groups with the rBm-SL3 protein showed it to be highly reactive with endemic normal sera compared to its reactivity with microfilaraemic and non-endemic normal sera. The immunoprotective efficacy of the rBm-SL3 antigen against B. malayi filarial infection was evaluated in susceptible host jirds (gerbils) (Meriones unguiculatus). Jirds immunised with the rBm-SL3 antigen showed 68% cytotoxicity against microfilariae and 67,69% cytotoxicity against infective larvae in in-vitro antibody-dependent cellular cytotoxicity assays and in-situ micropore chamber methods. Analysis of IgG subclasses against Bm-SL3 revealed a significant increase in IgG1 and IgG2 antibodies in endemic normal sera compared with other groups. Lymphocyte proliferation to Bm-SL3 was significantly higher in the endemic normal group compared with that in clinical and microfilarial carriers (p < 0.001). Significantly enhanced levels of IFN-, in the culture supernatant of peripheral blood mononuclear cells of endemic normal sera after stimulation with Bm-SL3 suggest that the cellular response in this group may have a Th1 bias. [source] Microsatellite and chromosomal stable colorectal cancers demonstrate poor immunogenicity and early disease recurrenceCOLORECTAL DISEASE, Issue 6 2009A. Banerjea Abstract Objective, Colorectal cancers may demonstrate chromosomal instability (CSI) or microsatellite instability (MSI-H). A third group of microsatellite and chromosome stable (MACS) colorectal cancer has been described more recently. Patients with MSI-H colorectal cancers demonstrate improved outcome and a pronounced inflammatory infiltrate. Enhanced host immune response and increased immunogenicity might explain these observations. This study aims to further characterize colorectal cancer immunogenicity. Method, Microsatellite stability status was determined in resected tumour samples. Microsatellite stable (MSS) tumour samples were stratified by DNA ploidy status, as determined by flow cytometry into aneuploid MSS (CSI) and diploid MSS (MACS) cancers. Lymphocyte proliferation, quantified by bromodeoxyuridine incorporation assays assessed tumour protein immunogenicity and ELISA assays quantified inflammatory cytokine release. Kaplan,Meier survival curves and multivariate analyses were used to determine prognostic value. Results, Patients with MSI-H colorectal cancer had improved outcome but those with MACS cancers undergoing curative surgery had significantly poorer disease-free survival (P = 0.002). The MACS phenotype was an independent predictor of poor outcome (HR = 2.44, 1.33,4.47, P = 0.004). Lymphocyte proliferation assays confirmed enhanced immunogenicity of MSI-H proteins and reduced immunogenicity of MACS proteins (P < 0.0001). In vitro levels of IFN-, (P = 0.004) and IL-18 (P < 0.0001) mirrored these differences in lymphocyte activity. Conclusions, Stratification of colorectal cancer by MSI and ploidy status may have prognostic value in patients undergoing curative surgery. MSI-H cancers display enhanced immunogenic properties but the immune response to MACS cancers appears to be absent and this may contribute to their poor prognosis. [source] Contaminant-associated alteration of immune function in black-footed albatross (Phoebastria nigripes), a North Pacific predatorENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 9 2007Myra E. Finkelstein Abstract Environmental pollution is ubiquitous and can pose a significant threat to wild populations through declines in fitness and population numbers. To elucidate the impact of marine pollution on a pelagic species, we assessed whether toxic contaminants accumulated in black-footed albatross (Phoebastria nigripes), a wide-ranging North Pacific predator, are correlated with altered physiological function. Blood samples from adult black-footed albatrosses on Midway Atoll, part of the Hawaiian (USA) archipelago, were analyzed for organochlorines (e.g., polychlorinated biphenyls [PCBs] and chlorinated pesticides), trace metals (silver, cadmium, tin, lead, chromium, nickel, copper, zinc, arsenic, selenium, and total mercury), and a sensitive physiological marker, peripheral white blood cell immune function (mitogen-induced lymphocyte proliferation and macrophage phagocytosis). We found a positive significant relationship between organochlorines, which were highly correlated within individual birds (p < 0.001, r > 0.80, Spearman correlation for all comparisons; PCBs, 160 ± 60 ng/ml plasma [mean ± standard deviation]; DDTs, 140 ± 180 ng/ml plasma; chlordanes, 7.0 ± 3.6 ng/ml plasma; hexachlorobenzene, 2.4 ± 1.5 ng/ml plasma; n = 15) and increased lymphocyte proliferation (p = 0.020) as well as percentage lymphocytes (p = 0.033). Mercury was elevated in black-footed albatrosses (4,500 ± 870 ng/ml whole blood, n = 15), and high mercury levels appeared to be associated (p = 0.017) with impaired macrophage phagocytosis. The associations we documented between multiple contaminant concentrations and immune function in endangered black-footed albatrosses provide some of the first evidence that albatrosses in the North Pacific may be affected by environmental contamination. Our results raise concern regarding detrimental health effects in pelagic predators exposed to persistent marine pollutants. [source] Association between lymphocyte proliferation and polychlorinated biphenyls in free-ranging harbor seal (Phoca vitulina) pups from British Columbia, CanadaENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 5 2005Milton Levin Abstract Recent pinniped die-offs have led to the speculation that persistent organic pollutants (POPs) are immunomodulatory, making individuals more susceptible to viral infections. Eighteen healthy harbor seal (Phoca vitulina) pups (aged 3,4 weeks) were live-captured from southern British Columbia, Canada, and maintained temporarily in captivity for an immunotoxicological assessment. The relationships between mitogen-induced peripheral blood lymphocyte proliferation and blubber concentrations of three major immunotoxic POP classes (the polychlorinated biphenyls [PCBs], polychlorinated dibenzo- p -dioxins [PCDDs], and the polychlorinated dibenzofurans [PCDFs]) were evaluated. A significant body weight-independent positive correlation was observed between both T-cell mitogen (phytohemagglutinin [PHA])- and B-cell mitogen (lipopolysaccharide [LPS])-induced lymphocyte proliferation and the blubber concentrations of total PCB. Best subset regression analysis revealed that total PCBs, and not total PCDD or total PCDF, explained 24 and 29% of the changes in both T-cell mitogen-and B-cell mitogen-induced lymphocyte proliferation, respectively. Further regression analysis performed on the PCB classes measured in this study showed that di - ortho PCBs accounted for 25 and 30% of the changes in both T-cell and B-cell lymphocyte proliferation, respectively. Results suggest that POPs, and PCBs in particular, are associated with changes in lymphocyte proliferation, something that could result in increased susceptibility to infections in harbor seal pups. Further research is needed to evaluate the relative roles of natural and contaminant-related influences on the immune system of marine mammals. [source] Prognostic significance of soluble interleukin-2 receptor levels in patients with dilated cardiomyopathyEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 6 2003C. J. Limas Abstract Background Activation of T lymphocytes is thought to mediate myocardial dysfunction in dilated cardiomyopathy (CMP), probably through cytotoxic cytokines, but its value as a prognostic factor has not been evaluated. Methods For 2 years we prospectively followed 76 patients (65 males, 11 females, age 49 ± 7 years) with CMP and New York Heart Association(NYHA) Class II,III heart failure; left ventricular (LV) function was assessed echocardiographically. Thirty-three patients (28 males, five females, age 52 ± 6 years) with ischaemic heart disease (IHD) and similar NYHA and LV function characteristics were used as controls. Serum sIL-2R levels, peripheral blood lymphocyte proliferation (basal, + concanavalin A) and HLA-DQB1 genotyping was carried out in all patients. Results The CMP patients had increased sIL-2R levels (1259 ± 130 pg mL,1) compared with the IHD patients (703 ± 80 pg mL,1, P < 0·01, only 3 > 800 pg mL,1). In the CMP patients, there was a significant (r = +0·45, P= 0·04) correlation between sIL-2R and the LV end-diastolic diameter but not with the LV ejection fraction or NYHA Class. During the 24-month follow up, 17 of the CMP patients had an adverse clinical course (death, need for cardiac transplantation, or worsening heart failure). Of these, 14 (75%) had elevated (, 800 pg mL,1) sIL-2R levels (Group I) compared with only five (6%) with a stable clinical course (Group II). Neither [3H] thymidine incorporation into the peripheral blood lymphocytes nor the excess of HLA-DQB1-30 histidine homozygotes in the Group I patients (38% vs. 17%, P < 0·05) could predict the clinical outcome. Conclusion Increased sIL-2R levels in CMP patients are an independent predictor of a more aggressive clinical course. [source] Study of cord blood natural killer cell suppressor activityEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 4 2001S. El Marsafy Abstract: We tested the immunosuppressive effect of cord blood (CB) natural killer (NK) cells using highly purified CB NK cells in mixed lymphocyte cultures (MLC) containing autologous CB T cells as responders. Control cultures were done without NK cells. Our findings revealed that CB NK cells induced a dose-dependent inhibition of T lymphocyte proliferation as evidenced by decreased 3H-thymidine incorporation in MLC. The T cell alloproliferation was significantly decreased in the presence of an NK cell to responder cell ratio of 0.1, 0.2 or 0.4 compared with control cultures done without NK cells (p=0.02, 0.003 and 0.0002, respectively). T lymphocyte inhibition was also achieved using irradiated CB NK cells and still demonstrable on addition of disparate CB NK and T cells to the MLC. In agreement with previous reports, adult blood NK cells inhibited the alloreactive T cells in the MLC using adult T lymphocytes as responders. Compared to control cultures done without NK cells, statistically significant inhibition of 3H-thymidine incorporation in MLC was observed at a ratio of NK cells to responder cells ratio of 0.2 or 0.4 (p=0.02). To investigate the mechanism whereby CB NK cells can interfere with the development of alloreactive T cells in MLC, we measured the tumour necrosis factor-, (TNF-,) concentrations in MLC supernatants using NK cell-depleted or unseparated CB mononuclear cells (MNC) as responders. The results revealed significantly high levels of TNF-, in the absence of NK cells (p=0.007). We conclude that CB NK cells suppress alloreactive T lymphocytes as do their counterparts in adult blood. However, the high NK to T cell ratio in CB could contribute to a more marked suppressive potential compared to that in adult blood. The mechanism of NK-mediated inhibition is likely related to disruption of the TNF-, pathway of T-lymphocyte activation. [source] Toll-like receptor 6-independent signaling by diacylated lipopeptidesEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 1 2005Ute Buwitt-Beckmann Abstract Bacterial lipopeptides are strong immune modulators that activate early host responses after infection as well as initiating adjuvant effects on the adaptive immune system. These lipopeptides induce signaling in cells of the immune system through Toll-like receptor 2 (TLR2),TLR1 or TLR2,TLR6 heteromers. So far it has been thought that triacylated lipopeptides, such as the synthetic N-palmitoyl-S-[2,3-bis(palmitoyloxy)-(2RS)-propyl]-(R)-cysteine (Pam3)-CSK4, signal through TLR2,TLR1 heteromers, whereas diacylated lipopeptides, like the macrophage-activating lipopeptide from Mycoplasma fermentans (MALP2) or S-[2,3-bis(palmitoyloxy)-(2RS)-propyl]-(R)-cysteine (Pam2)-CGNNDESNISFKEK, induce signaling through TLR2,TLR6 heteromers. Using new synthetic lipopeptide derivatives we addressed the contribution of the lipid and, in particular, the peptide moieties with respect to TLR2 heteromer usage. In contrast to the current model of receptor usage, not only triacylated lipopeptides, but also diacylated lipopeptides like Pam2CSK4 and the elongated MALP2 analog Pam2CGNNDESNISFKEK-SK4 (MALP2-SK4) induced B lymphocyte proliferation and TNF-, secretion in macrophages in a TLR6-independent manner as determined with cells from TLR6-deficient mice. Our results indicate that both the lipid and the N-terminal peptides of lipoproteins contribute to the specificity of recognition by TLR2 heteromers and are responsible for the ligand,receptor interaction on host cells. [source] Intraocular injection of tamoxifen-loaded nanoparticles: a new treatment of experimental autoimmune uveoretinitisEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 12 2004Yvonne de Kozak Abstract In this study, we tested the efficiency of an intravitreal injection of tamoxifen, a non-steroidal estrogen receptor modulator, in retinal soluble antigen (S-Ag)-induced experimental autoimmune uveoretinitis (EAU). To increase the bioavailability of tamoxifen, we incorporated tamoxifen into polyethylene glycol (PEG)-coated nanoparticles (NP-PEG-TAM). The localization of the nanoparticles within the eye was investigated using fluorescent-labeled PEG-coated nanoparticles after injection into the vitreous cavity of rats with EAU. Some nanoparticles were distributed extracellularly throughout the ocular tissues, others were concentrated in resident ocular cells and in infiltrating macrophages. Whereas the injection of free tamoxifen did not alter the course of EAU, injection of NP-PEG-TAM performed 1,2,days before the expected onset of the disease in controls resulted in significant inhibition of EAU. NP-PEG-TAM injection significantly reduced EAU compared to injection of NP-PEG-TAM with 17,-estradiol (E2), suggesting that tamoxifen is acting as a partial antagonist to E2. Diminished infiltration by MHC class,II+ inflammatory cells and low expression of TNF-,, IL-1,, and RANTES mRNA were noted in eyes of NP-PEG-TAM-treated rats. Intravitreal injection of NP-PEG-TAM decreased S-Ag lymphocyte proliferation, IFN-, production by inguinal lymph node cells, and specific delayed-type hypersensitivity indicative of a reduced Th1-type response. It increased the anti-S-Ag IgG1 isotype indicating an antibody class switch to Th2 response. These data suggest that NP-PEG-TAM inhibition of EAU could result from a form of immune deviation. Tamoxifen-loaded nanoparticles may represent a new option for the treatment of experimental uveitis. [source] CREB function is required for normal thymic cellularity and post-irradiation recoveryEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 7 2004Sven Baumann Abstract Recent generation of genetically modified Creb1 mutant mice has revealed an important role for CREB (cAMP responsive element binding protein) and the related proteins CREM (cAMP responsive element modulator) and ATF1 (activating transcription factor 1) in cell survival, in agreement with previous studies using overexpression of dominant-negative CREB (dnCREB). CREB and ATF1 are abundantly expressed in T cells and are rapidly activated by phosphorylation when T cells are stimulated through the T cell antigen receptor. We show that T cell-specific loss of CREB in mice, in combination with the loss of ATF1, results in reduced thymic cellularity and delayed thymic recovery following sublethal irradiation but no changes in T cell development or activation. These data show that loss of CREB function has specific effects on thymic T lymphocyte proliferation and homeostasis in vivo. [source] Comparative evaluation of intranasal and subcutaneous route of immunization for development of mucosal vaccine against experimental tuberculosisFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 1 2005Pramod K. Giri Abstract Activation of mucosal immunity in the respiratory tract is crucial for protection against respiratory infections. Whether the intranasal route of vaccination imparts better protection against pulmonary tuberculosis than that of subcutaneous vaccination remains a debatable issue. In this study, we have investigated the effect of the routes of immunization on the induction of immunoprotection against experimental tuberculosis employing mycobacterial culture filtrate proteins complexed with dimethyldioctadecylammonium bromide. Vaccination via intranasal and subcutaneous routes triggered immune activation in the spleen and cervical lymph node, while the former route of vaccination lead to higher antigen-specific lymphocyte proliferation, interferon-,, interleukin-12 and interleukin-4 responses in cervical lymph node and induction of antigen-specific IgA responses at mucosal level of the respiratory tract. Mice vaccinated via the intranasal route were found to be better protected against experimental tuberculosis particularly in lung compared to subcutaneous-immunized mice. These results emphasize the importance of the intranasal route vaccination in tuberculosis. [source] Evaluation of the impact of highly active antiretroviral therapy on immune recovery in antiretroviral naive patientsHIV MEDICINE, Issue 1 2004L Al-Harthi Objectives To examine the extent of immune reconstitution in treatment-naive patients with CD4 T-cell counts <500 cells/,L following 48 weeks of highly active antiretroviral therapy (HAART). Methods Thirteen antiretroviral naive patients were evaluated longitudinally for 48 weeks on HAART utilizing immune functional and lymphocyte phenotyping assays, including lymphocyte proliferation assay, flow cytometric evaluation of cell surface markers, and delayed type hypersensitivity skin tests. Virologic responses were monitored using commercially available viral load assays and gag/pol mRNA quantification using simultaneous immunophenotyping/UltraSensitive fluorescence in situ hybridization (ViroTect In Cell HIV-1 Detection Kit; Invirion, Frankfort, MI). Thymic function was evaluated for a subset of four patients using real-time polymerase chain reaction (PCR) for T-cell receptor excision circle (TREC) quantification and thymic scans using computerized axial tomography (CT) of the thymus. Results HAART initiation resulted in a significant decline in plasma viremia and percentage of infected peripheral blood cells, and a rise in CD4 T cells from a baseline median of 207 cells/,L to a week-48 median of 617 cells/,L. The rise was predominately in CD4 memory cells. Naive T cells also increased in number, but at a slower rate. Activated (HLA-DR CD38) CD4 and CD8 T cells were elevated at baseline (24 and 62%, respectively) and declined by week 48 (17 and 36%, respectively) but did not reach normal levels. The number of Fas CD4 T cells increased from a baseline median of 169 to 381 cells/,L at week 48. Both soluble interleukin (IL)-2 and tumour necrosis factor (TNF) II receptors declined by week 48. HIV p24 lymphocyte proliferation assay responses were transiently detected in three patients. TREC values increased from a median 6400 copies/,g at baseline to a week-48 median value of 26 697 copies/,g. Conclusion Immune functional reconstitution was not achieved in these HAART naive patients. [source] CD40-mediated enhancement of immune responses against three forms of influenza vaccineIMMUNOLOGY, Issue 1 2007Caterina Hatzifoti Summary There is potential for influenza A infections to cause massive morbidity and mortality. Vaccination may be the primary defence against pandemic influenza, and potential pandemic'flu vaccines may be produced conventionally, in embryonated eggs, or as recombinant protein or synthetic peptide vaccines. However the vaccines are produced, the supply may be limiting, and it will be important to enhance the immunogenicity of the vaccines as much as possible. We have shown that conjugation to CD40 binding antibody is a very efficient way of enhancing immune responses against model antigens, but were interested in assessing the effectiveness of this system using influenza vaccines. We produced conjugates of CD40 monoclonal antibody (mAb) and isotype control with three potential influenza vaccines: a peptide-based vaccine containing T- and B-cell epitopes from virus haemagglutinin; a whole, killed virus vaccine; and a commercially produced split virus vaccine. CD40 mAb conjugates in each case were more immunogenic, but the adjuvant effect of CD40 conjugation was greatest with the split vaccine, where antibody responses were enhanced by several hundred-fold after a single immunization, and lymphocyte proliferation in response to antigen in vitro was also strongly enhanced. [source] Effect of undernourishment on Herpes Simplex Virus Type 1 ocular infection in the Wistar rat modelINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 2 2002FABIÁN BENENCIA Abstract. ,We have studied the susceptibility to Herpes Simplex Virus Type 1 (HSV-1) infection in malnourished rats. Groups of 10 rats were undernourished during suckling by offspring duplication. The animals were put on commercial diet and at 1, 2, 3, 5 and 8 weeks after weaning, infected in the eye by scarification with HSV-1, strain F. Significant differences in morbidity and mortality were observed between malnourished and control groups infected three weeks after weaning. Viral titres were higher in ocular washings and brains obtained from the malnourished group. This group showed a diminution in antigen dependent lymphocyte proliferation compared to control, and significantly lower delayed type hypersensitivity reaction against inactivated virus (malnourished = 0.16 ± 0.02 mm, control = 0.26 ± 0.03 mm, p < 0.05). Neutralizing antibodies in serum were lower in the malnourished group and lower levels of interferon were obtained in the malnourished group 24 h post-infection. We conclude that malnutrition during suckling induces a delay in the capability to overcome HSV infection. [source] Selected Stro-1-enriched bone marrow stromal cells display a major suppressive effect on lymphocyte proliferationINTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 1 2009A. NASEF Summary Mesenchymal stem cells (MSCs) have an immunosuppressive effect and can inhibit the proliferation of alloreactive T cells in vitro and in vivo. Cotransplantation of MSCs and hematopoietic stem cells (HSCs) from HLA-identical siblings has been shown to reduce the incidence of acute graft- vs.-host disease. MSCs are heterogeneous and data on the inhibitory effects of different MSC subsets are lacking. The antigen Stro1 is a marker for a pure primitive MSC subset. We investigated whether Stro-1-enriched induce a more significant suppressive effect on lymphocytes in a mixed lymphocyte reaction (MLR), and whether this action is related to a specific gene expression profile in Stro-1-enriched compared to other MSCs. We demonstrated that the Stro-1-enriched population elicits a significantly more profound dose-dependent inhibition of lymphocyte proliferation in a MLR than MSCs. One thousand expanded Stro-1-enriched induced an inhibitory effect comparable to that of 10 times as many MSCs. Inhibition by Stro-1-enriched was more significant in contact-dependent cultures than in noncontact-dependant cultures at higher ratio. The Stro-1-enriched inhibitory effect in both culture types was linked to increased gene expression for soluble inhibitory factors such as interleukin-8 (IL-8), leukemia inhibitory factor (LIF), indoleamine oxidase (IDO), human leukocyte antigen-G (HLA-G), and vascular cell adhesion molecule (VCAM1). However, tumor growth factor-,1 (TGF-,) and IL-10 were only up-regulated in contact-dependant cultures. These results may support using a purified Stro-1-enriched population to augment the suppressive effect in allogeneic transplantation. [source] Influence of dietary ß-glucan on growth performance, lymphocyte proliferation, specific immune response and haptoglobin plasma concentrations in pigsJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 1-2 2003S. Hiss Summary Immunomodulatory feed additives might offer alternatives to anti-microbial growth promoters in swine production. The present study was conducted to assess the effects of ,-1,3/1,6 glucans, i.e. of specific yeast cell wall components, on immune function and growth performance in pigs. After weaning at 4 weeks of age, 75 piglets were allocated to 3 different groups for 4 weeks, the diet was supplemented with 0, 0.015 or 0.03% of ,-glucan, respectively. All animals were vaccinated against porcine reproductive and respiratory syndrome (PRRS). After 4 weeks, average daily gains (ADG) of ,-glucan treated pigs were not different from the controls. Feed intake was tendentiously (p < 0.1) increased at 0.03%,-glucan, without alteration of feed efficiency. Serum haptoglobin concentrations at the end of the 4 week treatment were increased in all groups when compared to the initial levels (p < 0.001), without differences between the groups (p > 0.05). Haptoglobin levels were inversely related to ADG. Lymphocyte proliferation indices were not different in control and treatment groups. Specific vaccination responses, as quantified by the PRRS antibody titres occurred in all animals, but no relation with ,-glucan feeding was observed. Our results indicate marginal benefits of ,-glucan supplements for growth performance and no effect on the immune parameters tested. The observed trend towards increased feed intake needs further elucidation. [source] Novel role of extracellular carbon dioxide in lymphocyte proliferation in cultureJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 2 2001Ranjana Chakrabarti Abstract CO2/HCO3, buffering system is indispensable to maintain the pH of culture media for long-term cell culture. Now-a-days, the zwiterionic hydrogen buffer HEPES is widely used as an additional buffer in the commonly used culture media. There are reports on the successful use of HEPES-buffered media, under CO2/HCO3, free conditions, for long-term cell cultures. However, still CO2/HCO3, buffering system is widely used. We aimed at investigating the reason for this. We found that lymphocytes proliferate in response to concanavalin A only in HCO3, -buffered medium in the presence of 5% CO2, but not in the HEPES-buffered medium in the absence of CO2. However, lymphocyte proliferation was observed in HEPES-buffered medium in the presence of 5% CO2 and in the absence of HCO3,. On the other hand, a low level proliferation was observed in HEPES-buffered medium supplemented with HCO3, in the absence of CO2. Supplementation of the culture medium with TCA cycle intermediates and the precursors for the salvage pathway of nucleotide synthesis did not support the lymphocyte proliferation at all. Based on these findings and other reports, we suggest that extracellular CO2 plays a novel role in cell proliferation. J. Cell. Biochem. 83: 200,203, 2001. © 2001 Wiley-Liss, Inc. [source] Comparison of ATP production in whole blood and lymphocyte proliferation in response to phytohemagglutininJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 5 2007Nancy H. Augustine Abstract Lymphocyte proliferation in response to mitogens, phytohemagglutinin (PHA), concanavalin A, pokeweed, and/or specific antigens has been the method of choice for in vitro diagnosis of cell-mediated immune dysfunction. Recently, an assay to measure intracellular adenosine triphosphate (ATP) production in response to PHA has been developed that requires a shorter, overnight incubation. We compared a standard 5- to 7-day lymphocyte mitogen stimulation assay utilizing tritiated thymidine (3H-thy) incorporation to one in which ATP production in response to PHA by CD4-positive cells is measured in a luminometer that requires only 18,24,hr. A total of 20 patient samples suspected of having decreased cell-mediated immunity submitted for mitogen induced lymphocyte proliferation and 21 normal controls were tested in both assays. A comparison of these two methods has demonstrated that the screening ATP assay has a sensitivity at 24,hr of 100% in detecting decreased PHA induced lymphocyte proliferation at 5 days and a specificity of 85% in the samples obtained from normal controls. The data indicate that the ATP assay may be a useful screening tool for more rapid detection of blood samples with decreased cell-mediated immune responses. However, a positive screen should always be confirmed by 3H-thy uptake using mitogens and recall antigens like candida and tetanus. J. Clin. Lab. Anal. 21:265,270, 2007. © 2007 Wiley-Liss, Inc. [source] Pharmacodynamic interaction of recombinant human interleukin-10 and prednisolone using in vitro whole blood lymphocyte proliferationJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 5 2002Abhijit Chakraborty Abstract Prednisolone, a commonly used synthetic corticosteroid, and IL-10, a cytokine under investigation for strong antiinflammatory properties, are being contemplated as a potential joint therapeutic regimen in immune disorders. Their pharmacodynamic interactions were examined in blood from healthy adult male and female volunteers using an in vitro phytohemagglutinin (PHA)-stimulated whole,blood lymphocyte proliferation technique. Isobolograms along with parametric competitive and noncompetitive interaction models were used to determine the nature and intensity of interactions. Single drug effects show prednisolone more efficacious in inhibiting lymphocyte proliferation with an IC50 of 3.3 ng/mL and Imax value of 1, signifying complete suppression. Analogous parameters for IL-10 were 16.2 ng/mL for IC50 and 0.89 for Imax. There were no significant differences in the single drug immunosuppressive effects among genders. Their joint effects showed additive interaction based on isobolographic analysis. Parametric analysis using the competitive interaction model described their interaction as slightly synergistic, while the noncompetitive interaction modeling indicate a small degree of antagonism. Also, the joint effects in females tend to be more antagonistic than males. Concomitant use of prednisolone and IL-10 should thus reflect the net additive responses to concentrations of each agent. © 2002 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 91:1334,1342, 2002 [source] Amelioration of doxorubicin-induced myocardial oxidative stress and immunosuppression by grape seed proanthocyanidins in tumour-bearing miceJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 8 2005Xiao-Yu Zhang We have investigated the protective effects of grape seed proanthocyanidins on doxorubicin-induced toxicity in tumour-bearing mice. The intraperitoneal administration of doxorubicin (2 mg kg,1 every other day, cumulative dosage for 18 mg kg,1) significantly inhibited the growth of sarcoma 180, and induced myocardial oxidative stress with decreased superoxide dismutase and glutathione peroxidase activity while increasing malondialdehyde formation in the heart or serum. Doxorubicin-induced myocardial oxidative stress also reduced lactate dehydrogenase and creatine kinase activity in the heart and elevated their levels in the serum. Doxorubicin also affected immune functions of tumour-bearing mice with significantly decreased interleukin-2 (IL-2) and interferon-, (INF-,) production, and slightly decreased natural killer (NK) cell cytotoxicity, lymphocyte proliferation and CD4+/CD8+ ratio. It markedly increased the percentages of cytotoxic T cells (CD3+CD8+), helper T cells (CD3+CD4+), IL-2R+CD4+, and IL-2R+ cells as compared with untreated tumour-bearing mice. The intragastric administration of proanthocyanidin (200 mg kg,1 daily) significantly inhibited tumour growth, and increased NK cell cytotoxicity, lymphocyte proliferation, CD4+/CD8+ ratio, IL-2 and INF-, production. Moreover, proanthocyanidin strongly enhanced the anti-tumour effect of doxorubicin and the above immune responses, and completely eliminated myocardial oxidative stress induced by doxorubicin. In conclusion, intragastric administration of proanthocyanidin could enhance the anti-tumour activity of doxorubicin and ameliorate doxorubicin-induced myocardial oxidative stress and immunosuppression in tumour-bearing mice. [source] Immunoreactivity of peptides generated by limited proteolysis of 71-kDa cell wall protein of Mycobacterium tuberculosis H37Ra using PLG-microparticlesLETTERS IN APPLIED MICROBIOLOGY, Issue 5 2000N. Dhiman Peptide mapping by limited proteolysis of a highly protective 71-kDa cell wall-associated protein of Mycobacterium tuberculosis H37Ra was carried out in order to identify key protective determinants within the native protein. The 71-kDa protein, which had an isoelectric point of 4·25, was digested into eight major bands at 48 h using trypsin and pepsin at equal enzyme to protein ratios (pH 5·5). The in vitro lymphocyte reactivity of individual peptides suggested P1, P2 and P5 to be significantly immunoreactive in mice immunized with native 71-kDa-polylactide-coglyeolide (PLG); however, the reactivity was significantly lower than that of the native 71-kDa protein. Immunization of mice with a pooled fraction (upper fraction-71 kDa) of more immunoreactive peptides (consisting of P1 and P2) did not further boost their immunoreactivity. However, P1 and P2 exhibited comparable or even higher lymphocyte proliferation in human tuberculous and control subjects. These data suggest distinct antigenic specificities in humans and mice and further substantiate the use of the 71-kDa protein or its peptides P1 and P2 as potential vaccine candidates for tuberculosis. [source] Reactivity to sodium tetrachloropalladate (Na2[PdCl4]) compared to PdCl2 and NiCl2 in lymphocyte proliferation testsALLERGY, Issue 8 2009J. Muris Background:, For patch testing, replacement of the commonly used palladium dichloride (PdCl2) by sodium tetrachloropalladate (Na2[PdCl4]) was recently demonstrated to improve test accuracy and show a significant correlation with nickel (Ni), supporting the concept of cross-reactivity between Pd and Ni. A promising alternative to metal allergy patch testing is the in vitro lymphocyte proliferation test (LTT). Objectives:, The aim of this study was to test whether Na2[PdCl4] is also more sensitive for diagnosing Pd allergy with a standardized LTT. Patients/methods:, After determining optimal nontoxic and nonmitogenic concentrations for Na2[PdCl4], blood samples from 105 patients with clinical suspicion of metal allergy were tested with an LTT called memory lymphocyte immuno stimulation assay for Na2[PdCl4], PdCl2 and NiCl2. Reaction profiles were analysed for concordant positive reactions. Results:, Using the conventional cut-off of stimulation index , 3, 74.3% showed a positive reaction to NiCl2, 15.2% to PdCl2 and 28.6% to Na2[PdCl4]. All positive results to PdCl2 were covered by Na2[PdCl4]. From the 30 positive reactions to Na2[PdCl4], 26 (87%) were concordant for NiCl2 reactivity. Conclusion:, In LTT, the use of Na2[PdCl4] results in more positive reactions in Pd allergy testing which are in concordance with positive reactions to PdCl2 and NiCl2. [source] Treponema denticola immunoinhibitory protein induces irreversible G1 arrest in activated human lymphocytesMOLECULAR ORAL MICROBIOLOGY, Issue 3 2004W. Lee Oral spirochetes may contribute to the pathogenesis of a number of disorders including periodontal and periradicular diseases; however, the mechanism (s) by which these organisms act to cause disease is unknown. We have previously shown that extracts of the oral spirochete, Treponema denticola, contain an immunosuppressive protein (Sip) which impairs human lymphocyte proliferation. The objective of this study was to determine the mechanism by which Sip alters the proliferative response of lymphocytes. Human T-cells were activated by PHA in the presence or absence of Sip and cell cycle progression was assessed by flow cytometry. Cell cycle distribution was based upon DNA, RNA and protein content as well as expression of the activation markers; CD69 and IL-2R. Seventy-two hours following activation with PHA, cells were found in the G0, G1, S and G2/M phases of the cell cycle. In contrast, pretreatment with Sip resulted in a significant reduction of cells in the S and G2/M phases and a concomitant increase in the G1 phase. Sip did not alter the expression of the early activation markers CD69 and CD25R. To determine if G1 arrest resulted in activation of the checkpoint and cell death, we also monitored Sip-treated cells for apoptosis. Indeed, treatment with Sip resulted in both DNA fragmentation and caspase activation after 96 h. Our results indicate that Sip induces G1 arrest in human T-cells and, furthermore, that the arrest is irreversible, culminating in activation of the apoptotic cascade. We propose that if cell cycle arrest occurs in vivo, it may result in local and/or systemic immunosuppression and thereby enhance the pathogenicity of spirochetes and/or that of other opportunistic organisms. [source] Update: Effects of Antioxidant and Non-Antioxidant Vitamin Supplementation on Immune FunctionNUTRITION REVIEWS, Issue 5 2007Aimee L. Webb PhD The purpose of this manuscript is to review the impact of supplementation with vitamins E and C, carotenoids, and the B vitamins on parameters of innate and adaptive immune function as reported from clinical trials in humans. There is evidence to support causal effects of supplementation with vitamins E and C and the carotenoids singly and in combination on selected aspects of immunity, including the functional capacity of innate immune cells, lymphocyte proliferation, and the delayed-type hypersensitivity (DTH) response. Controlled intervention trials of B vitamin-containing multivitamin supplements suggest beneficial effects on immune parameters and clinical outcomes in HIV-positive individuals [source] CD4+ T cells mediate mucosal and systemic immune responses to experimental hookworm infectionPARASITE IMMUNOLOGY, Issue 6 2010B. DONDJI Summary Hookworm infection is associated with anaemia and malnutrition in many resource-limited countries. Ancylostoma hookworms have previously been shown to modulate host cellular immune responses through multiple mechanisms, including reduced mitogen-mediated lymphocyte proliferation, impaired antigen presentation/processing, and relative reductions in CD4+ T cells in the spleen and mesenteric lymph nodes. Syrian hamsters were depleted of CD4+ for up to 9 days following intraperitoneal injection (200 ,g) of a murine anti-mouse CD4 monoclonal IgG (clone GK1·5). CD4+ T-cell-depleted hamsters infected with the hookworm Ancylostoma ceylanicum exhibited a threefold higher mean intestinal worm burden and more severe anaemia than animals that received isotype control IgG. In addition, depletion of CD4+ T cells was associated with impaired cellular and humoral (serum and mucosal) immune responses to hookworm antigens. These data demonstrate an effector role for CD4+ T cells in hookworm immunity and disease pathogenesis. Ultimately, these studies may yield important insights into the relationship between intestinal nematode infections and diseases that are associated with CD4+ T-cell depletion, including HIV. [source] | ||||||||||||||||||||||||||||||||||