Positive T Cells (positive t + cell)

Distribution by Scientific Domains


Selected Abstracts


Phenotypic analysis of peripheral CD4+ CD8+ T cells in the rat

IMMUNOLOGY, Issue 2 2000
E. Kenny
Summary Among peripheral T cells, the expression of CD4 and CD8 is almost mutually exclusive. However, here we show, using flow cytometric analysis, that ex vivo approximately 6% of rat T cells stained for both CD4 and CD8. These double positive cells were also detected by confocal microscopy. Only around 50% of double positive cells expressed the CD8, chain, the remaining cells expressed the CD8, chain alone. Double positive cells were blast-like with a phenotype, distinct from that of either CD4 or CD8 single positive cells, suggestive of an activated state. Previous reports of double positive T cells have also suggested that coexpression of CD4 and CD8 is linked to the activation state of the cell. There was an indication that priming animals with a hapten-carrier complex increased the ratio of CD8,,,:,,, expressing double positive T cells, although we did not detect an increase in the frequency of double positive T cells following priming. We also show that the frequency of double positive cells was reduced following thymectomy and with age. In conclusion, these studies show that peripheral T cells expressing both CD4 and CD8 can be detected in the rat and that they are phenotypically distinct from CD4 and CD8 single positive T cells. [source]


Interleukin-23 promotes Th17 differentiation by inhibiting T-bet and FoxP3 and is required for elevation of interleukin-22, but not interleukin-21, in autoimmune experimental arthritis

ARTHRITIS & RHEUMATISM, Issue 4 2010
Adriana M. C. Mus
Objective To examine the role of interleukin-23 (IL-23) in subgroup polarization of IL-17A,positive and/or interferon-, (IFN,),positive T cells in autoimmune disease,prone DBA/1 mice with and without collagen-induced arthritis. Methods A magnetic-activated cell sorting system was used to isolate CD4+ T cells from the spleen of naive and type II collagen (CII),immunized DBA/1 mice. These CD4+ T cells were stimulated in vitro under Th0, Th1, or different Th17 culture conditions. Intracellular staining for IL-17A and IFN, was evaluated by flow cytometry. In addition, Th17 cytokines and T helper,specific transcription factors were analyzed by enzyme-linked immunosorbent assay and/or quantitative polymerase chain reaction. Results In CD4+ T cells from naive DBA/1 mice, IL-23 alone hardly induced retinoic acid,related orphan receptor ,t (ROR,t), Th17 polarization, and Th17 cytokines, but it inhibited T-bet expression. In contrast, transforming growth factor ,1 (TGF,1)/IL-6 was a potent inducer of ROR,t, ROR,, IL-17A, IL-17F, IL-21, and FoxP3 in these cells. In contrast to TGF,1/IL-6, IL-23 was critical for the induction of IL-22 in CD4+ T cells from both naive and CII-immunized DBA/1 mice. Consistent with these findings, IL-23 showed a more pronounced induction of the IL-17A+IFN,, subset in CD4+ T cells from CII-immunized mice. However, in CD4+ T cells from naive mice, IL-23 significantly increased the TGF,1/IL-6,induced Th17 polarization, including elevated levels of IL-17A and IL-17F and decreased expression of T-bet and FoxP3. Of note, the IL-23,induced increase in IL-17A and IL-17F levels was prevented in T-bet,deficient mice. Conclusion IL-23 promotes Th17 differentiation by inhibiting T-bet and FoxP3 and is required for elevation of IL-22, but not IL-21, levels in autoimmune arthritis. These data indicate different mechanisms for IL-23 and TGF,1/IL-6 at the transcription factor level during Th17 differentiation in autoimmune experimental arthritis. [source]


Peritoneal T Cell Responses Can Be Polarized Toward Th1 or Th2 in Children on Chronic Peritoneal Dialysis

ARTIFICIAL ORGANS, Issue 8 2004
Sabrina Chiesa
Abstract:, Peritoneal T cell responses can be polarized toward Th1 or Th2 in children on chronic peritoneal dialysis. Previous studies on the peritoneal immune system described the presence of activated T lymphocytes in peritoneal effluents from subjects on chronic peritoneal dialysis (CPD). Since Th1/Th2 polarized response can influence the outcome of specific infectious diseases, we investigated if activated Th1/Th2 cells can be detected in peritoneal effluents during peritoneal dialysis, in order to better understand the role of T cells in the mechanisms of peritoneal defense. We have studied 8 children (4 males, 4 females, mean age 5.8 ± 5.7 years, range 0.3,13.4) on CPD. Peritoneal cells have been isolated from peritoneal effluents by centrifugation. Immunofluorescent staining of intracellular cytokines for flow cytometric analysis was used to detect the percentage of T cells producing either IFN-, (Th1) or IL-4 (Th2). In the initial study 3 months after CPD initiation, high percentages of IFN-, positive peritoneal T cells (38% and 63%) were detected in two subjects; this finding is consistent with a Th1 polarization of peritoneal T cells. In another subject, high percentages of IL-4 positive T cells (31%) were detected, suggesting a Th2 polarization of peritoneal T cell response. Small amounts of either Th1 or Th2 T cells (2,4%) were also detected in the other subjects. At the 1 year follow-up, Th1 polarization persisted in one subject (18% IFN-, positive peritoneal T cells), in another a shift from Th1 to Th2 was observed, and in the other subject a down regulation of both T cell subsets occurred. The finding that a predominance of T cells producing either IFN-, or IL-4 was found in 3 out of 8 children strongly suggests that peritoneal T cell responses can be polarized toward Th1 or Th2. The decrease of Th1 and/or Th2 polarized T cells in the peritoneum of 4 out of 6 subjects (after 1 year) suggests that CPD can play an immunosuppressive role on T cell peritoneal responses. Further studies are needed in order to define whether different T helper activation patterns are associated with a higher risk of peritoneal infection or of peritoneal damage. [source]


Immunohistological study of infiltrated cells and cytokines in murine herpetic keratitis

ACTA OPHTHALMOLOGICA, Issue 5 2001
Tomoyuki Inoue
ABSTRACT. Purpose: To identify localization and kinetics of infiltrated cells and cytokines in murine herpetic keratitis. Methods: HSV-1 was inoculated onto the scarified BALB/c corneas. At given times post infection (PI), eyes were removed and studied immunohistochemically using monoclonal antibodies against several infiltrated cells and cytokines. Results: Neutrophils and NK cells infiltrated as early as 1 day PI reaching a maximum number at 2 day PI in initial stage. ,, TCR positive cells were observed in the corneal stroma from 1 day PI to 8 day PI. IL-2 and IFN-, were positive in the cell-infiltrated areas of the epithelial and stromal lesions, whereas IL-4 was negative throughout the experiment. Conclusion: Our results indicated that cytokine profile upon herpes infection on the cornea is Th1 dominant. Together with neutrophils in the early phase of infection, ,, positive T cells may play an additional role in protecting the cornea against incoming pathogens. [source]


Recombinase-activating gene 1 immunodeficiency: different immunological phenotypes in three siblings

ACTA PAEDIATRICA, Issue 6 2009
Srdjan Pasic
Abstract We report different immunological phenotypes in three siblings from consanguineous family with recombinase-activating gene 1 (RAG1) gene mutations. Null mutations of RAG genes result in severe combined immunodeficiency (SCID) with absent T and B cells. Hypomorphic mutations with retained activity of RAG genes may lead to a ,leaky' SCID with some features of Omenn syndrome (OS) or typical OS. In our three patients, homozygous, hypomorphic RAG1 gene mutation (g.368,369delAA) was detected. Two patients presented with T,B,SCID phenotype while the youngest patient developed T+B+NK+SCID phenotype with expansion of autologous T-cell receptor (TCR) ,,-positive T cells, increased immunoglobulin levels and retained ability for antibody production. Similar to originally reported patients with this newly recognized immune phenotype, our patient developed disseminated cytomegalovirus (CMV) infection and autoimmune cytopenia. Conclusion: In infants with disseminated cytomegalovirus infection and autoimmune cytopenia, even if basic immunologic investigation appears normal, RAG1 immunodeficiency should be considered. [source]