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Cell-mediated Immune Response (cell-mediated + immune_response)
Selected AbstractsRelative abundance of males to females affects behaviour, condition and immune function in a captive population of dark-eyed juncos Junco hyemalisJOURNAL OF AVIAN BIOLOGY, Issue 3 2007Timothy J. Greives Relative numbers of males and females in breeding groups may vary from expected values owing to a variety of factors. To determine how sex ratio might influence individual phenotypes in a captive population of dark-eyed juncos Junco hyemalis during the breeding season, we established three treatment groups: a male-biased (2:1), equal (1:1), and female-biased group (1:2). Within-group density (birds/m2) was constant across groups. We assessed the frequency of flight chases (a proxy for social instability), measured changes in body mass and pectoral muscle condition, assayed plasma levels of testosterone (T) and compared cell-mediated immunity of individuals. We found significantly more chases in the male-biased group than in the female-biased group. Birds in the male-biased group lost more mass and displayed poorer pectoral-muscle condition than birds in the equal group. Cell-mediated immune responses were reduced in individuals in the male-biased group in comparison to the female-biased group. Plasma T levels in both sexes did not vary with sex ratio. Collectively, these results suggest that during the breeding season, social instability is greater in male-biased populations, and instability may lead to decreased general health and vigour. [source] The importance of exposure estimation in the assessment of skin sensitization riskCONTACT DERMATITIS, Issue 5 2000Michael K. Robinson The development of new ingredients and products for the consumer market requires a thorough assessment of their potential for skin sensitization and the possible clinical manifestation of allergic contact dermatitis. The process by which low molecular weight chemicals induce and elicit skin sensitization reactions is complex and dependent on many factors relevant to the ability of the chemical to penetrate the skin, react with protein, and trigger the cell-mediated immune response. These major factors include inherent potency, chemical dose, duration and frequency of exposure, vehicle or product matrix, and occlusion. The fact that a chemical is a contact allergen does not mean that it cannot be formulated into a consumer product at levels well tolerated by most individuals. Many common ingredients (e.g., fragrances, preservatives) are known skin allergens. However, all allergens show dose-response and threshold characteristics. Therefore, one should be able to incorporate these chemicals into products at levels that produce acceptably low incidences of skin sensitization under foreseeable conditions of exposure. The critical exposure determinant for evaluating skin sensitization risk is dose per unit area of skin exposed. Use of this parameter allows for comparative assessments from different types of skin sensitization tests (including cross-species comparisons), and, at least for known potent allergens, there is remarkable similarity in threshold dose/unit area determinations across species. The dose/unit area calculation enables a judgment of the sensitization risk for different product types. This is illustrated using the chemical preservative methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) as a case study. [source] Signaling pathways in Th2 developmentIMMUNOLOGICAL REVIEWS, Issue 1 2004Kerri A. Mowen Summary:, In order for an immune response to be successful, it must be of the appropriate type and magnitude. Intracellular residing pathogens require a cell-mediated immune response, whereas extracellular pathogens evoke a humoral immune response. T-helper (Th) cells orchestrate the immune response and are divided into two subsets, Th1 and Th2 cells. Here, we discuss the mechanisms of Th2 development with a focus on signal transduction pathways that influence Th2 differentiation. [source] Stepwise regulation of TH1 responses in autoimmunity: IL-12-related cytokines and their receptorsINFLAMMATORY BOWEL DISEASES, Issue 8 2005Christoph Becker PhD Abstract Interleukin (IL)-12 is a key cytokine of cell-mediated immune responses. Until recently, IL-12 was believed to be unique in its ability to induce the differentiation of naive T cells toward the TH1 phenotype and in its pathogenic activity, as shown in various disease models including inflammatory bowel disease. However, recently, 2 additional cytokines closely related to IL-12, IL-23 and IL-27, were discovered. Until then, the role of IL-12 was overestimated because it was believed that the p40 subunit was unique to IL-12. The discovery that IL-12 shares p40 with IL-23 and that IL-23 but not IL-12 is essential in models of chronic inflammation and autoimmunity led to a model in which IL-12 is essential to induce interferon-,-producing TH1 cells, whereas IL-23 mediates effector functions. The latest cytokine added to this cytokine family is IL-27. IL-27 has the unique feature to act on naive T cells, rendering them susceptible to IL-12 signaling. Thus, IL-27 may be essential for the early events of a cell-mediated immune response. This review focuses on these novel cytokines and their role in cell-mediated immune responses and discusses differences and common features within the family of IL-12-related cytokines. [source] Gamma,delta T cell subsets are differentially associated with granuloma development and organization in a bovine model of mycobacterial diseaseINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 6 2009Brandon L. Plattner Summary The characteristic lesion in bovine tuberculosis is well-organized respiratory granulomas. This is typically associated with a strong T-helper 1 biased cell-mediated immune response and eventual containment of the infection. In bovine paratuberculosis, the classic lesion is unorganized granulomatous intestinal inflammation. Clinical paratuberculosis is associated with a T-helper 2 biased humoral immune response and eventual death because of inability of the host to contain the infection. Recent reports have suggested that gamma,delta (,,) T cells play a significant role in granuloma development and/or maintenance during initial stages of infection and may influence the subsequent adaptive immune response. The objective of this study was to use an in vivo bovine model to evaluate ,, T cells during the early host immune response to mycobacterial infection. We used immunofluorescent staining, hyperspectral microscopy, and computerized assisted morphometry to evaluate staining and distribution of ,, T cells during development of organized and unorganized granulomas. Our data suggest that bovine ,, T cell subsets are differentially recruited to early infection sites, and may be instrumental during the initial antimycobacterial host immune response as well as for granuloma organization. [source] The novel application of an immunological technique reveals the immunosuppressive effect of phytoestrogens in Betta splendensJOURNAL OF FISH BIOLOGY, Issue A 2006D. R. Ardia The novel application of a standard technique to assess cell-mediated immune response to phytohaemagglutinin (PHA) injected in the caudal peduncle in a small fish (<2 g) to test the immunosuppressive effect of three phytoestrogens: genistein, equol and ,-sitosterol is described. Individual Betta splendens exposed to these oestrogenic chemicals produced weaker inflammatory responses to PHA than did control individuals, suggesting that phytoestrogens are immunosuppressive. This technique should enable immune function in fish species, too small to provide sufficient blood for conventional immunological measures, to be assessed. [source] Postoperative serum attenuates LPS-induced release of TNF-, in orthopaedic surgeryJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 10 2007Olav Reikerås Abstract Studies with ex vivo stimulation of whole blood samples from injured patients have revealed a diminished production capacity for a broad range of secretory products, including inflammatory cytokines. Recent interest has focused on the release of mediators in serum that depress the cell-mediated immune response following trauma. The involvement of the lipid mediator prostaglandin E2 (PGE2) has been assumed because it is a potent endogenous immunosuppressor. In the present study, we tested the hypothesis that inhibitory substances circulating in the patient's serum after a major musculoskeletal trauma might impair leukocyte function by evaluating the effect of such serum on cytokine release in a whole blood model. Six females and three males undergoing elective total hip replacement were included in the study. Ex vivo LPS-induced TNF-, and IL-10 were measured in whole blood sampled preoperatively and added serum taken before, at the end of operation, and at postoperative days 1 and 6 with saline as negative control. LPS induced significant releases of TNF-, and IL-10 in whole blood. Addition of preoperative, postoperative, and day-1 postoperative serum did not alter the LPS-induced release of TNF-, as compared to saline. In the presence of serum from postoperative day 6, however, the expression of TNF-, was significantly reduced as compared to saline and preoperative serum (p,=,0.021 and 0.008, respectively). Neither of the serum samples altered the release of IL-10. PGE2 was significantly (p,=,0.008) increased in serum at postoperative day 6 as compared to preoperative levels. In conclusion, these data show that at day 6 after major orthopaedic surgery, the patient serum contained activity that inhibited ex vivo LPS-induced TNF-, release. The potent TNF-, inhibitory activity found at day 6 after injury correlated with increased levels of PGE2 and indicates cell-mediated hyporesponsiveness to a second stimulus. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:1395,1400, 2007 [source] Effects of various anti-asthmatic agents on mite allergen-pulsed murine bone marrow-derived dendritic cellsCLINICAL & EXPERIMENTAL ALLERGY, Issue 7 2005I. Machida Summary Background Dendritic cells (DCs) play an important role in the immune response and are critically involved in asthma. ,2 -agonists could potentially exacerbate type 2 T helper (Th2) cell-mediated immune response. Objectives To determine the effects of various anti-asthmatic agents on DCs function both in vitro and in vivo. Methods Murine bone marrow-derived DCs were pulsed with mite allergen in the presence of pranlukast, salbutamol, salmeterol or fluticasone. These DCs were then inoculated intranasally into naïve mice to induce allergic airway inflammation in vivo. Results Pranlukast reduced IL-10 and increased IL-12, while fluticasone reduced both IL-10 and IL-12 production by mite allergen-pulsed DCs. Allergic airway inflammation in pranlukast- and fluticasone-treated and mite allergen pulsed DCs-harbouring mice was attenuated and such response was associated with inhibition of Th2 response in the airway. Salbutamol did not alter cytokine production, while salmeterol reduced IL-12 production by mite allergen-pulsed DCs. Lung pathology in ,2 -agonist-harbouring mice was comparable with those of mite allergen-pulsed DCs-harbouring mice. Conclusions Our results indicate that leukotriene receptor antagonists and corticosteroids inhibit DCs-induced Th2 skewed immune response, and that short- and long-acting ,2 -agonists do not modify DCs-induced allergic airway inflammation. [source] TLR9 stimulation drives naïve B cells to proliferate and to attain enhanced antigen presenting functionEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 8 2007Wei Jiang Abstract Mechanisms that regulate naïve B cell proliferation and function are incompletely defined. In this study, we test the hypothesis that naïve B cell expansion, survival and ability to present antigen to T,lymphocytes can be directly modulated by Toll-like receptor (TLR) agonists. In the absence of B cell receptor stimulation, CpG oligonucleotide, a TLR9 agonist, was particularly efficient in inducing naïve B cell proliferation and survival. Although the expanded naïve B cells did not mature into CD27+ or IgG+ memory B cells, these cells did differentiate into IgM-secreting cells with increased surface expression of HLA-DR, CD40 and CD80. This was associated with an increased potential for these B cells to activate allogeneic T cells. We propose that the activation and expansion of naïve B cells induced by TLR9 agonists could enhance the potential of these cells to interact with cognate antigens and facilitate cell-mediated immune responses. [source] Polymeric Materials for Gene Delivery and DNA VaccinationADVANCED MATERIALS, Issue 8 2009David N. Nguyen Abstract Gene delivery holds great potential for the treatment of many different diseases. Vaccination with DNA holds particular promise, and may provide a solution to many technical challenges that hinder traditional vaccine systems including rapid development and production and induction of robust cell-mediated immune responses. However, few candidate DNA vaccines have progressed past preclinical development and none have been approved for human use. This Review focuses on the recent progress and challenges facing materials design for nonviral DNA vaccine drug delivery systems. In particular, we highlight work on new polymeric materials and their effects on protective immune activation, gene delivery, and current efforts to optimize polymeric delivery systems for DNA vaccination. [source] Induction of dendritic cell-mediated immune responses against HIV-1 by antigen-capturing nanospheres in miceJOURNAL OF MEDICAL VIROLOGY, Issue 1 2005Masaki Kawamura Abstract Prophylactic vaccines, designed to elicit potent humoral and cellular immune responses to human immunodeficiency virus type 1 (HIV-1) antigens in mucosa, are the important approach to the protection of individuals against HIV-1 infection, since HIV-1 transmission is largely a result of sexual contact. In this study, a novel strategy has been developed to induce HIV-1-specific immune responses, which involves inactivated HIV-1-caputring concanavalin A (Con A)-immobilized nanospheres (HIV-NS) and their interaction with bone marrow (BM)-derived dendritic cells. HIV-NS were taken up by dendritic cells via cytoskeleton-dependent but mannose-binding site-independent phagocytosis. Serial stimulations to unprimed T-cells with HIV-1 gp120-capturing NS-pulsed dendritic cells could induce antigen-specific T-cell response. Intranasal administration of fluorescein isothiocyanate-labeled nanospheres (NS) in mice proved that the particles were taken up into pulmonary dendritic cells. Analysis of mice receiving intranasal immunizations with HIV-NS revealed that the mice efficiently induced the antibodies against HIV-1 in the genital tract and specific cytotoxic T-cells in the spleen. These results suggest that the use of HIV-1-NS may provide a novel and promising approach for the induction of humoral and cellular immune responses to HIV-1. J. Med. Virol. 76:7,15, 2005. © 2005 Wiley-Liss, Inc. [source] | ||||||||||||||||||||||