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Cytotoxic Lymphocytes (cytotoxic + lymphocyte)
Selected AbstractsFCRL6 distinguishes mature cytotoxic lymphocytes and is upregulated in patients with B-cell chronic lymphocytic leukemiaEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 11 2008Daniel M. Schreeder Abstract Fc receptor-like 6 (FCRL6), the most recently characterized member of the FCRL family, is a cell surface glycoprotein with tyrosine-based regulatory potential. An extensive survey of human hematopoietic tissues disclosed that FCRL6 expression by NK- and T-cell subpopulations increases as a function of differentiation and is remarkably restricted to mature lymphocytes with cytotoxic capability. In particular, FCRL6 distinguishes perforin-expressing CD56dim NK cells, V,1+ and V,2+ ,, T cells, effector and effector memory CD8+ T cells, and rare cytotoxic CD4+ T cells in adult tissues. Analysis of this receptor in B-cell chronic lymphocytic leukemia (CLL) was also performed. FCRL6 was found to mark significantly expanded populations of cytotoxic CD8+ T, CD4+ T, and NK cells in patients with CLL. Despite sequence homology with the known Fc receptors for IgG and IgE, FCRL6 did not bind Ig. Although FCRL6 can be tyrosine-phosphorylated, its antibody-mediated ligation was unable to influence cellular activation. Collectively, these results demonstrate that FCRL6 is a distinct indicator of cytotoxic effector lymphocytes that is upregulated in diseases characterized by chronic immune stimulation. [source] Apoptosis induction by interleukin-2-activated cytotoxic lymphocytes in a squamous cell carcinoma cell line and Daudi cells , involvement of reactive oxygen species-dependent cytochrome c and reactive oxygen species-independent apoptosis-inducing factorsIMMUNOLOGY, Issue 2 2003Tetsuya Yamamoto Summary Investigation of the induction of apoptosis by cytotoxic lymphocytes has mainly focused on the signalling associated with Fas and its adaptor proteins. The signal pathway via mitochondria, however, has not been sufficiently elucidated in cytotoxic lymphocyte-induced apoptosis. We examined the release of mitochondrial proapoptotic factors by lymphokine-activated killer (LAK) cells in two cell lines. LAK cell-induced DNA fragmentation of the target cells was suppressed to approximately 50% of control levels by the addition of neutralizing monoclonal antibody to Fas and a granzyme B inhibitor. When intracellular reactive oxygen species (ROS) were scavenged, the LAK cell-induced DNA fragmentation was decreased to approximately 60% of the non-treated cell level. Co-cultivation of Daudi cells with LAK cells increased cytosolic and mitochondrial ROS levels. Activation of procaspase-3 and apoptosis by treatment of oral squamous cell carcinoma cells (OSC) with LAK cells was partially inhibited by pretreatment of OSC cells with ROS scavengers and mitochondrial complex inhibitors. Furthermore, cytochrome c and apoptosis-inducing factor (AIF) were released from mitochondria by OSC cell treatment with supernatants of LAK cells. The supernatant-induced cytochrome c release was suppressed by mitochondrial complex inhibitors, but the inhibitors did not inhibit the release of AIF. These results indicate that LAK cells induce target cell apoptosis via not only the Fas/Fas ligand system and granzyme B, but also ROS-dependent cytochrome c and ROS-independent AIF release. [source] Influence of HLA-DR2 on perforin-positive cells in pulmonary tuberculosisINTERNATIONAL JOURNAL OF IMMUNOGENETICS, Issue 5 2007D. N. Rajeswari Summary Perforin is one of the key effector molecules of cytotoxic T cells and natural killer cells. The influence of HLA-DRB1 alleles on peripheral blood perforin-positive CD4, CD8, CD16 and CD56 cells was studied by flow cytometry. HLA-DRB1 typing was done in normal healthy subjects (NHS: n = 156) and patients with pulmonary tuberculosis (PTB: n = 102) by polymerase chain reaction-based sequence-specific oligonucleotide hybridization method. We observed a significantly decreased percentage of total perforin-positive cells (per+) (P = 0.0004); CD8+/Per+ (P = 0.0005); CD16+/Per+ (P = 0.05) and CD56+/Per+ cells (P = 0.001) in HLA-DR2-positive PTB patients compared to non-DR2 patients. Subtyping of HLA-DR2-positive subjects at the allelic level revealed that the percentage of CD8+/Per+ cells did not differ among DRB1*1501 and DRB1*1502 patients while a trend towards a decreased percentage of CD16+/Per+ and CD56+/Per+ cells was noticed in DRB1*1501 patients compared to DRB1*1502 patients. The present study suggests that HLA-DR2 may be associated with down-regulation of perforin-positive cytotoxic lymphocytes and natural killer cells in pulmonary tuberculosis. [source] Lupus erythematosus panniculitis (lupus profundus): Clinical, histopathological, and molecular analysis of nine casesJOURNAL OF CUTANEOUS PATHOLOGY, Issue 6 2005Cesare Massone Background:, The diagnosis of lupus erythematosus panniculitis (LEP) may be very difficult in cases in which involvement of the subcutaneous fat is the only manifestation of the disease. The main differential diagnosis is subcutaneous panniculitis-like T-cell lymphoma (SPTCL). Methods:, We performed a retrospective study reviewing the histopathologic features of 11 biopsy specimens from nine patients with LEP (M : F = 2 : 7; median age: 48 years; range: 20,71 years). Results:, Histopathologically, all biopsies revealed a lobular panniculitis, with concomitant septal involvement in 82% of them. Dermal changes included the presence of superficial and deep infiltrates (82%) and mucin deposition (73%). The majority of cases (73%) presented also some form of epidermal involvement. The subcutaneous infiltrate was composed of lymphocytes in all cases, admixed with plasma cells in 91% of cases. Lymphoid follicles with reactive germinal centers were detected in 45% of cases. Immunohistochemistry showed a predominance of ,/,-T-helper and cytotoxic lymphocytes in 80% of cases admixed with B lymphocytes. The polymerase chain reaction analysis of the T-cell receptor (TCR)-, gene showed a polyclonal smear in all cases. Conclusions:, Our study shows that the most useful histopathologic criteria for distinguishing LEP from SPTCL are the presence of involvement of the epidermis, lymphoid follicles with reactive germinal centers, mixed cell infiltrate with prominent plasma cells, clusters of B lymphocytes, and polyclonal TCR-, gene rearrangement. [source] HIV and SIV infection: the role of cellular restriction and immune responses in viral replication and pathogenesisAPMIS, Issue 5-6 2009KENNETH C. WILLIAMS The human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) have a long biological history. Both viruses evolved from Africa and remnants of them can be found in the ,fossil record' of several species in which they are not endemic. SIV remains endemic in several species of monkeys in Africa where it does not cause immune deficiency. HIV and SIV actively replicate within humans and Asian non-human primates, despite cellular and genetic viral restriction factors and genes, and at times robust innate and adaptive immune responses. While Lentiviruses are considered ,slow viruses' it is clear in humans and susceptible Asian monkeys that virus production is rapid and highly active. This results in a massive loss of CD4+ memory effector T cells early after infection and a continued race between viral evolution, cytotoxic lymphocytes, and failed neutralizing antibody responses. Concurrently, HIV and SIV can infect monocyte/macrophage populations in blood and more importantly in tissues, including the central nervous system, where the virus can remain sequestered and not cleared by anti-retroviral therapy, and hide for years. This review will discuss species and cellular barriers to infection, and the role of innate and acquired immunity with infection and pathogenesis of HIV and SIV in select species. [source] Bacillus Calmette-Guérin cell-wall skeleton enhances the killing activity of cytotoxic lymphocyte-activated human dendritic cells transduced with the prostate-specific antigen geneBJU INTERNATIONAL, Issue 11 2009Reona Fujii OBJECTIVE To determine whether dendritic cells (DC) transduced with the prostate-specific antigen (PSA) gene can induce PSA-specific cytotoxic lymphocytes (CTL) against prostate cancer cells, and whether bacillus Calmette-Guérin (BCG) cell-wall skeleton (CWS) can enhance the maturation of DC-PSA and the killing activity of subsequently induced PSA-specific CTL. MATERIALS AND METHODS We generated an adenovirus encoding the PSA gene (AxCA-PSA) using the cosmid-terminal protein complex method. DC were infected with AxCA-PSA using the centrifugal method. The ability of CTL to lyse target cells expressing PSA, i.e the PSA-positive prostate cancer cell line, LNCap, and PSA-transduced autologous phytohaemagglutinin (PHA) blasts expressing PSA, was assessed using the 51Cr-release assay. The maturation of DC-PSA stimulated by BCG-CWS was assayed by flow cytometry. The cytotoxic activity enhanced by BCG-CWS was assessed by the 51Cr-release assay. RESULTS DC-PSA induced PSA-specific CTL with 85% cytotoxic activity against LNCaP (effector: target ratio, E:T, of 50:1). However, the cytotoxic activity against PSA-negative cells was very low. Anti-CD8 and anti-major histocompatibility (MHC) class I antibodies blocked PSA-specific cytotoxicity. The PSA-specific killing was reproducible against autologous PHA blast cells expressing PSA, independently of human leukocyte antigen haplotype. Furthermore, the combination of DC-PSA with BCG-CWS remarkably enhanced the PSA-specific cytotoxicity against PHA blasts expressing PSA (15,30% at an E:T ratio of 50:1). CONCLUSION These findings suggest that DC-PSA can induce MHC class I-restricted PSA-specific CD8+ CTL responses and that DC-PSA matured by BCG-CWS enhance PSA-specific cytotoxicity. The combination of DC-PSA with BCG-CWS might be a useful approach for treating advanced prostate cancer. [source] Selective effects of Lactobacillus casei Shirota on T cell activation, natural killer cell activity and cytokine productionCLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 2 2010H. Dong Summary Modulation of host immunity is an important potential mechanism by which probiotics confer health benefits. This study was designed to investigate the effects of a probiotic strain, Lactobacillus casei Shirota (LcS), on immune function using human peripheral blood mononuclear cells (PBMC) in vitro. In addition, the role of monocytes in LcS-induced immunity was also explored. LcS promoted natural killer (NK) cell activity and preferentially induced expression of CD69 and CD25 on CD8+ and CD56+ subsets in the absence of any other stimulus. LcS also induced production of interleukin (IL)-1,, IL-6, tumour necrosis factor (TNF)-,, IL-12 and IL-10 in the absence of lipopolysaccharide (LPS). In the presence of LPS, LcS enhanced IL-1, production but inhibited LPS-induced IL-10 and IL-6 production, and had no further effect on TNF-, and IL-12 production. Monocyte depletion reduced significantly the impact of LcS on lymphocyte activation, cytokine production and natural killer (NK) cell activity. In conclusion, LcS activated cytotoxic lymphocytes preferentially in both the innate and specific immune systems, which suggests that LcS could potentiate the destruction of infected cells in the body. LcS also induced both proinflammatory and anti-inflammatory cytokine production in the absence of LPS, but in some cases inhibited LPS-induced cytokine production. Monocytes play an important role in LcS-induced immunological responses. [source] | ||||||||||