Abstract P225: Rupp Rat Model Cd4+ T Cells Activate Nk Cells And Cause Mitochondrial Oxidative Stress And Hypertension In Normal Pregnant Rats

Hypertension ◽  
2020 ◽  
Vol 76 (Suppl_1) ◽  
Author(s):  
Evangeline M Deer ◽  
Kristin Reeve ◽  
Lorena M Amaral ◽  
Venkata Ramana Vaka ◽  
Michael Franks ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
T Cells ◽  
T Cell ◽  
Nk Cells ◽  
Rat Model ◽  
Adoptive Transfer ◽  
Cd4 T Cells ◽  
Cd4 T Cell ◽  
Pregnant Rats ◽  
Atp Production

Preeclampsia (PE) is new onset hypertension during pregnancy and is associated with elevated inflammatory response such as CD4+ T cells, NK cells, and cytokines. We have previously shown women with PE exhibit increases in circulating and placental CD4+T cells and placental mitochondrial (mt) dysfunction/ROS compared to normal pregnant (NP) women. The Reduced Uterine Perfusion Pressure (RUPP) rat model produces many characteristics of PE such as hypertension, increases in CD4+ cells, increases in renal and placental NK cells, and mt dysfunction/ROS. We have previously demonstrated that RUPP CD4+T cells cause hypertension in NP rats, however the role of RUPP CD4+ T cells in stimulating NK cells to cause mt dysfunction/ROS are not elucidated. Therefore, we examined the effect of adoptive transfer of RUPP CD4+ T cells to activate NK cells in NP rats. Splenic CD4+ T cells were isolated from RUPP rats, cultured, and injected into NP rats on GD 13. On GD19, MAP values and blood/tissue samples were collected from both RUPP CD4+ T cell recipients and NP controls. Mitochondrial respiration and mtROS were measured in isolated mitochondria using the Oxygraph 2K and fluorescent microplate reader, respectively. A student’s t-test was used for statistical analysis. On GD19, MAP increased to 110±2 mmHg (n=13) in RUPP CD4+ T cell recipients compared to control NP rats 102±2 mmHg (n=7, p<0.05). Circulating cytolytic NK cells increased to 3±0.6% in RUPP CD4+ T cell recipients (n=8) compared to NP controls 0.3±0.2% (n=7, p<0.05). Placental state 3 (209.3±31.3 vs 422.7 ±83.3 pmol/sec/mg, p<0.05) and maximal (152.1±46.2 vs 229.7±58.9 pmol/sec/mg) and renal state 3 (133.4 ±21.4 vs 289.8±43.4 pmol/sec/mg, p<0.05) and maximal (61.8±18 vs 242.4±27.7 pmol/sec/mg, p<0.05) respiration rates, indicative of ATP production and electron transport chain efficacy respectively, were reduced with RUPP CD4+ T cells (n=6; n=9) compared to NP (n=5; n=5). Collectively, the data indicate that the adoptive transfer of RUPP CD4+ T cells stimulates cytolytic NK cells and placental and renal mitochondrial dysfunction/ROS during pregnancy as important mechanisms of hypertension in the pathophysiology of preeclampsia. Keywords: Preeclamspia, Hypertension, Oxidative stress

CD4+ T Cells from RUPP rat model activate NK cells and cause mitochondrial oxidative stress and hypertension in normal pregnant rats

2020 ◽  
Vol 34 (S1) ◽  
pp. 1-1
Author(s):  
Evangeline Deer ◽  
Kristin E. Reeve ◽  
Lorena M. Amaral ◽  
Venkata Ramana Vaka ◽  
Michael Franks ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
T Cells ◽  
Nk Cells ◽  
Rat Model ◽  
Cd4 T Cells ◽  
Pregnant Rats ◽  
Mitochondrial Oxidative Stress

scholarly journals CD4+ T cells cause renal and placental mitochondrial oxidative stress as mechanisms of hypertension in response to placental ischemia

2021 ◽  
Vol 320 (1) ◽  
pp. F47-F54
Author(s):  
Evangeline Deer ◽  
Kristin E. Reeve ◽  
Lorena Amaral ◽  
Venkata Ramana Vaka ◽  
Michael Franks ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
T Cells ◽  
T Cell ◽  
Mitochondrial Dysfunction ◽  
Nk Cells ◽  
Cd4 T Cells ◽  
Cd4 T Cell ◽  
Mitochondrial Oxidative Stress ◽  
Uterine Perfusion ◽  
Placental Ischemia

The reduced uterine perfusion pressure (RUPP) rat model and normal pregnant (NP) rat recipients of RUPP CD4+ T cells recapitulate many characteristics of preeclampsia such as hypertension and oxidative stress. We have shown an important hypertensive role for natural killer (NK) cells to cause mitochondrial dysfunction in RUPP rats; however, the role for RUPP CD4+ T cells to stimulate NK cells is unknown. Therefore, we hypothesized that RUPP-induced CD4+ T cells activate NK cells to cause mitochondrial dysfunction/reactive oxygen species (ROS) as mechanisms of hypertension during pregnancy. We tested our hypothesis by adoptive transfer of RUPP CD4+ T cells into NP rats or by inhibiting the activation of RUPP CD4+ T cells with Orencia (abatacept) and examining hypertension, NK cells, and mitochondrial function. RUPP was performed on gestation day (GD) 14, and splenic CD4+ T cells were isolated on GD 19 and injected into NP rats on GD 13. In a separate group of rats, Orencia was infused and the RUPP procedure was performed. Mean arterial pressure and placental and renal mitochondrial ROS increased in RUPP ( n = 7, P < 0.05) and NP + RUPP CD4+ T-cell recipients ( n = 13, P < 0.05) compared with control NP ( n = 7) and NP + NP CD4+ T-cell recipients ( n = 5) but was reduced with Orencia ( n = 13, P < 0.05). Placental and renal respiration was reduced in RUPP ( n = 6, P < 0.05) and NP + RUPP CD4+ T-cell recipients ( n = 6, state 3 P < 0.05) compared with NP ( n = 5) and NP + NP CD4+ T-cell recipients ( n = 5) but improved with Orencia ( n = 9, n = 8 P < 0.05). These data indicate that CD4+ T cells, independent of NK cells, cause mitochondrial dysfunction/ROS contributing to hypertension in response to placental ischemia during pregnancy.

scholarly journals Borna disease, a progressive meningoencephalomyelitis as a model for CD4+ T cell-mediated immunopathology in the brain.

1989 ◽  
Vol 170 (3) ◽  
pp. 1045-1050 ◽  
Author(s):  
J A Richt ◽  
L Stitz ◽  
H Wekerle ◽  
R Rott
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Line ◽  
Mhc Class Ii ◽  
Adoptive Transfer ◽  
Cd4 T Cells ◽  
Immune Cell ◽  
Cd4 T Cell ◽  
The Brain ◽  
Borna Disease

A homogeneous T cell line NM1 with Borna disease (BD) virus reactivity could be established. The NM1 cells have been characterized as CD4+ T cells. Adoptive transfer revealed that this MHC class II-restricted immune cell is responsible for the immunopathological effect leading to BD, a progressive meningoencephalomyelitis.

The Expression Level of HLA-E on Activated T Cells Determines Their Fate When Activated NK Cells Were Nearby Present.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1529-1529
Author(s):  
Sumiko Takao ◽  
Takayuki Ishikawa ◽  
Takashi Uchiyama
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
Nk Cells ◽  
Cd4 T Cells ◽  
Cd4 T Cell ◽  
Expression Level ◽  
T Cell Proliferation ◽  
Target Cells ◽  
Concanamycin A

Abstract Background: Recent studies demonstrated that natural killer (NK) cells play a regulatory role in immune responses. As for the interaction with T cells, NK cells coordinate T cell responses through not only influencing dendritic cell function, but also directly acting on T cells. Besides secreting several kinds of cytokines, NK cells also kill activated autologous T cells. However, whether NK cell-mediated cytotoxicity has any role in the primary T cell response remains elusive. Methods: Peripheral blood samples were obtained from healthy volunteers with written informed consent. Naïve CD25− CD4+ T cells, NK cells, and monocytes were isolated with magnetic beads. Monocyte-derived dendritic cells (MoDCs) were generated and either immature MoDCs (ImMoDCs) or LPS-stimulated MoDCs (LPS-MoDCs) were used. Naïve CD4+ T cells cultured with allogeneic MoDCs (allo-MoDCs) in the presence or absence of autologous NK cells pre-activated by IL-18 and IL-15. Naïve CD4+ T cells were labeled with PKH67 dye before culture and proliferation of CD4+T cells was detected by the dilution of PKH67 signals by flow cytometry. Results: We found that activated NK cells substantially inhibited CD4+ T cell proliferation in response to allo-MoDCs. The addition of cytokines such as IL-2 could not restore CD4+ T cell proliferation. However, NK cells were not able to inhibit CD4+ T cell growth when they were separated by a transmembrane. Even when naïve CD4+ T cells were cultured with LPS-MoDCs, which were resistant to NK-lysis, CD4+ T cell proliferation was also inhibited. Furthermore, even when activated NK cells were added to the culture after naïve CD4+ T cells were stimulated with allo-MoDCs for 24 hours, CD4+ T cell proliferation were also inhibited. These data suggested that NK cells directly acted on CD4+ T cells in this assay. Then we performed 4-hour cyototoxicity assays, in which activated (CD25+) CD4+ T cells isolated from the culture of naïve CD4+ T cells and allo-MoDCs at various time points were used as target cells and activated NK cells were used as effecter cells. Resting naïve CD4+ T cells were resistant to NK-lysis. However, at day 1, activated CD4+ T cells became susceptible. ImMoDC-stimulated CD4+ T cells were remarkably susceptible to NK-lysis, whereas LPS-DC-stimulated CD4+ T cells were relatively resistant. NK cells pretreated with concanamycin A could not lyse activated CD4+ T cells, indicating that killing was mediated by release of lytic granules. In contrast, at day 3, CD4+ T cells activated with either ImMoDCs or LPS-MoDCs were completely resistant to NK-lysis. We then analyzed the kinetics of MICA/B and HLA-E expression on naïve CD4+ T cells stimulated with allo-MoDCs. MICA/B expression, which was slightly induced at day 1 and peaked at day 3, was comparable between CD4+ T cells stimulated with ImMoDCs and those with LPS-MoDCs. Addition of blocking antibody against NKG2D to cytotoxic assays did not affect the susceptibility of activated CD4+ T cells to NK-lysis. In contrast, in agreement with the susceptibility to NK-lysis, HLA-E expression at day 1 was considerably higher on LPS-MoDC-stimulated CD4+ T cells than ImMoDC-stimulated CD4+ T cells. At day 3, HLA-E expression was further up-regulated, and similar expression levels were observed in both ImMoDC-stimulated CD4+ T cells and LPS-MoDC-stimulated CD4+ T cells. In addition, antibody-dependent blockade of the HLA-E-NKG2A interaction abrogated the relative resistance to NK-lysis of LPS-MoDC- stimulated CD4+ T cells at day 1. Conclusions and Discussion: Naïve CD4+ T cells became transiently susceptible to NK-lysis shortly after stimulated with allo-MoDCs, and, in our assay, NK-lysis of activated CD4+ T cells is the major mechanisms by which NK cells inhibited the proliferation of CD4+ T cells. High level of HLA-E expression on activated CD4+ T cells prevents NK-lysis. These data suggest that the expression level of HLA-E on activated CD4+ T cells determines their fate when activated NK cells are nearby present. HLA-E and NKG2A may become a new target of immunoregulation.

scholarly journals Reduced immune-regulatory molecule expression on human colonic memory CD4 T cells in older adults

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Stephanie M. Dillon ◽  
Tezha A. Thompson ◽  
Allison J. Christians ◽  
Martin D. McCarter ◽  
Cara C. Wilson
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Older Persons ◽  
Age Groups ◽  
T Cell Immunity ◽  
Cd4 T Cell ◽  
Cell Immunity ◽  
Memory Cd4 T Cells

Abstract Background The etiology of the low-level chronic inflammatory state associated with aging is likely multifactorial, but a number of animal and human studies have implicated a functional decline of the gastrointestinal immune system as a potential driver. Gut tissue-resident memory T cells play critical roles in mediating protective immunity and in maintaining gut homeostasis, yet few studies have investigated the effect of aging on human gut T cell immunity. To determine if aging impacted CD4 T cell immunity in the human large intestine, we utilized multi-color flow cytometry to measure colonic lamina propria (LP) CD4 T cell frequencies and immune-modulatory marker expression in younger (mean ± SEM: 38 ± 1.5 yrs) and older (77 ± 1.6 yrs) adults. To determine cellular specificity, we evaluated colon LP CD8 T cell frequency and phenotype in the same donors. To probe tissue specificity, we evaluated the same panel of markers in peripheral blood (PB) CD4 T cells in a separate cohort of similarly aged persons. Results Frequencies of colonic CD4 T cells as a fraction of total LP mononuclear cells were higher in older persons whereas absolute numbers of colonic LP CD4 T cells per gram of tissue were similar in both age groups. LP CD4 T cells from older versus younger persons exhibited reduced CTLA-4, PD-1 and Ki67 expression. Levels of Bcl-2, CD57, CD25 and percentages of activated CD38+HLA-DR+ CD4 T cells were similar in both age groups. In memory PB CD4 T cells, older age was only associated with increased CD57 expression. Significant age effects for LP CD8 T cells were only observed for CTLA-4 expression, with lower levels of expression observed on cells from older adults. Conclusions Greater age was associated with reduced expression of the co-inhibitory receptors CTLA-4 and PD-1 on LP CD4 T cells. Colonic LP CD8 T cells from older persons also displayed reduced CTLA-4 expression. These age-associated profiles were not observed in older PB memory CD4 T cells. The decline in co-inhibitory receptor expression on colonic LP T cells may contribute to local and systemic inflammation via a reduced ability to limit ongoing T cell responses to enteric microbial challenge.

scholarly journals The Impact of Exercise Serum on Selected Parameters of CD4+ T Cell Metabolism

Immuno ◽  
2021 ◽  
Vol 1 (3) ◽  
pp. 119-131
Author(s):  
Jana Palmowski ◽  
Kristina Gebhardt ◽  
Thomas Reichel ◽  
Torsten Frech ◽  
Robert Ringseis ◽  
...  
Keyword(s):  
T Cells ◽  
Oxygen Consumption ◽  
T Cell ◽  
Real Time ◽  
Cd4 T Cells ◽  
Cell Metabolism ◽  
Cd4 T Cell ◽  
Autologous Serum ◽  
Cell Phenotype ◽  
The Impact

CD4+ T cells are sensitive to peripheral changes of cytokine levels and metabolic substrates such as glucose and lactate. This study aimed to analyze whether factors released after exercise alter parameters of human T cell metabolism, specifically glycolysis and oxidative phosphorylation. We used primary human CD4+ T cells activated in the presence of autologous serum, which was collected before (CO) and after a 30-min exercise intervention (EX). In the course of activation, cells and supernatants were analyzed for cell viability and diameter, real-time oxygen consumption by using PreSens Technology, mRNA expression of glycolytic enzymes and complexes of the electron transport chain by real-time PCR, glucose, and lactate levels in supernatants, and in vitro differentiation by flow cytometry. EX did not alter T cell phenotype, viability, or on-blast formation. Similarly, no difference between CO and EX were found for CD4+ T cell activation and cellular oxygen consumption. In contrast, higher levels of glucose were found after 48 h activation in EX conditions. T cells activated in autologous exercise serum expressed lower HK1 mRNA and higher IFN-γ receptor 1. We suggest that the exercise protocol used was not sufficient to destabilize the immune metabolism of T cells. Therefore, more intense and prolonged exercise should be used in future studies.

scholarly journals Infection of HLA-DR1 Transgenic Mice with a Human Isolate of Influenza A Virus (H1N1) Primes a Diverse CD4 T-Cell Repertoire That Includes CD4 T Cells with Heterosubtypic Cross-Reactivity to Avian (H5N1) Influenza Virus

2009 ◽  
Vol 83 (13) ◽  
pp. 6566-6577 ◽  
Author(s):  
Katherine A. Richards ◽  
Francisco A. Chaves ◽  
Andrea J. Sant
Keyword(s):  
T Cells ◽  
Influenza Virus ◽  
T Cell ◽  
Avian Influenza ◽  
Avian Influenza Virus ◽  
Cd4 T Cells ◽  
Cross Reactivity ◽  
Cd4 T Cell ◽  
Ns1 Protein ◽  
Infected Cells

ABSTRACT The specificity of the CD4 T-cell immune response to influenza virus is influenced by the genetic complexity of the virus and periodic encounters with variant subtypes and strains. In order to understand what controls CD4 T-cell reactivity to influenza virus proteins and how the influenza virus-specific memory compartment is shaped over time, it is first necessary to understand the diversity of the primary CD4 T-cell response. In the study reported here, we have used an unbiased approach to evaluate the peptide specificity of CD4 T cells elicited after live influenza virus infection. We have focused on four viral proteins that have distinct intracellular distributions in infected cells, hemagglutinin (HA), neuraminidase (NA), nucleoprotein, and the NS1 protein, which is expressed in infected cells but excluded from virion particles. Our studies revealed an extensive diversity of influenza virus-specific CD4 T cells that includes T cells for each viral protein and for the unexpected immunogenicity of the NS1 protein. Due to the recent concern about pandemic avian influenza virus and because CD4 T cells specific for HA and NA may be particularly useful for promoting the production of neutralizing antibody to influenza virus, we have also evaluated the ability of HA- and NA-specific CD4 T cells elicited by a circulating H1N1 strain to cross-react with related sequences found in an avian H5N1 virus and find substantial cross-reactivity, suggesting that seasonal vaccines may help promote protection against avian influenza virus.

scholarly journals Isolevuglandin-Modified Cardiac Proteins Drive CD4+ T Cell Activation in the Heart and Promote Cardiac Dysfunction

Circulation ◽  
2021 ◽  
Author(s):  
Njabulo Ngwenyama ◽  
Annet Kirabo ◽  
Mark Aronovitz ◽  
Francisco Velázquez ◽  
Francisco Carrillo-Salinas ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Antigen Presentation ◽  
T Cell Activation ◽  
Cardiac Dysfunction ◽  
Cd4 T Cells ◽  
Cell Activation ◽  
Cd4 T Cell ◽  
Myocardial Oxidative Stress

Background: Despite the well-established association between T cell-mediated inflammation and non-ischemic heart failure (HF), the specific mechanisms triggering T cell activation during the progression of HF and the antigens involved are poorly understood. We hypothesized that myocardial oxidative stress induces the formation of isolevuglandin (IsoLG)-modified proteins that function as cardiac neoantigens to elicit CD4+ T cell receptor (TCR) activation and promote HF. Methods: We used transverse aortic constriction (TAC) in mice to trigger myocardial oxidative stress and T cell infiltration. We profiled the TCR repertoire by mRNA sequencing of intramyocardial activated CD4+ T cells in Nur77 GFP reporter mice, which transiently express GFP upon TCR engagement. We assessed the role of antigen presentation and TCR specificity in the development of cardiac dysfunction using antigen presentation-deficient MhcII -/- mice, and TCR transgenic OTII mice that lack specificity for endogenous antigens. We detected IsoLG-protein adducts in failing human hearts. We also evaluated the role of reactive oxygen species (ROS) and IsoLGs in eliciting T cell immune responses in vivo by treating mice with the antioxidant TEMPOL, and the IsoLG scavenger 2-hydroxybenzylamine (2-HOBA) during TAC, and ex-vivo in mechanistic studies of CD4+ T cell proliferation in response to IsoLG-modified cardiac proteins. Results: We discovered that TCR antigen recognition increases in the left ventricle (LV) as cardiac dysfunction progresses, and identified a limited repertoire of activated CD4+ T cell clonotypes in the LV. Antigen presentation of endogenous antigens was required to develop cardiac dysfunction since MhcII -/- mice reconstituted with CD4+ T cells, and OTII mice immunized with their cognate antigen were protected from TAC-induced cardiac dysfunction despite the presence of LV-infiltrated CD4+ T cells. Scavenging IsoLGs with 2-HOBA reduced TCR activation and prevented cardiac dysfunction. Mechanistically, cardiac pressure overload resulted in ROS dependent dendritic cell accumulation of IsoLG-protein adducts which induced robust CD4+ T cell proliferation. Conclusions: Collectively, our study demonstrates an important role of ROS-induced formation of IsoLG-modified cardiac neoantigens that lead to TCR-dependent CD4+ T cell activation within the heart.

scholarly journals 739 Intratumor childhood vaccine-specific CD4+ T cell recall helps antitumor CD8 T cells

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A770-A770
Author(s):  
Michael Brown ◽  
Zachary McKay ◽  
Yuanfan Yang ◽  
Darell Bigner ◽  
Smita Nair ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Viral Replication ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Cd4 T Cell ◽  
Antitumor Efficacy ◽  
Polio Vaccine ◽  
Recall Antigen ◽  
Childhood Vaccine

BackgroundPVSRIPO, a recombinant poliovirus derived from the live-attenuated Sabin oral polio vaccine strain, is being tested in multi-institutional phase II clinical trials for recurrent glioblastoma (NCT04479241) and unresectable, PD-1 refractory melanoma (NCT04577807) in combination with PD1 blockade. PVSRIPO capsid is identical to the Sabin vaccine strain and >99% identical to the inactivated Polio vaccine (IPOL, Salk), against which public health mandated childhood vaccination is near universal. In non-vaccinated mice, PVSRIPO mediates antitumor efficacy in a replication-dependent manner via engaging innate inflammation and antitumor T cells. Accordingly, it is anticipated that pre-existing immunity to PVSRIPO impedes antitumor therapy. However, recent evidence indicates that immunological 'recall', or reactivation of memory T cells, may mediate anti-tumor effects.MethodsThe impact of prior polio vs control (KLH) vaccination on intratumor viral replication, tumor inflammation, and overall tumor growth after intratumor PVSRIPO therapy was assessed in murine tumor models. The role of polio capsid and tetanus recall antigens in mediating intratumor inflammation and antitumor efficacy was similarly studied in mice non-permissive to PVSRIPO infection. To mechanistically define antitumor effects of polio recall, B cell and CD8 T cell knockout mice were used, in addition to adoptive transfer of CD4+ T cells from vaccinated mice. Intratumor polio or tetanus recall antigen therapy was performed after OT-I transfer (OVA-specific T cells) in the B16-OVA melanoma model to gauge antitumor T cell activity. Lastly, the inflammatory effects of polio and tetanus antigens was tested in human peripheral blood mononuclear cells (PBMCs).ResultsDespite curtailing intratumor viral replication, prior polio vaccination in mice potentiated subsequent antitumor efficacy of PVSRIPO. Intratumor recall responses induced by polio and tetanus antigens also delayed tumor growth. Recall antigen therapy was associated with marked intratumor influx of eosinophils, conventional CD4+ T cells, and increased expression of IFN-g, TNF, and Granzyme B in tumor infiltrating T cells. The antitumor efficacy of polio recall antigen was mediated by CD4+ T cells, partially depended upon CD8+ T cells, and was impaired by B cells. Both polio and tetanus recall antigen therapy bolstered the antitumor function of tumor-specific OT-I CD8+ T cells. Polio and tetanus antigens induced CXCL10 and type I/II/III IFNs in PBMCs in vitro.ConclusionsChildhood vaccine-specific CD4+ T cells hold cancer immunotherapy potential. In the context of PVSRIPO therapy, antitumor and inflammatory effects of polio vaccine-specific CD4+ T cell recall supersedes inhibitory effects of attenuated intratumor viral replication, and represents a novel mechanism of action.Ethics ApprovalThe animal work described in this study was approved by the Duke University IACUC.

CD4+ T cells specific for glycoprotein B from cytomegalovirus exhibit extreme conservation of T-cell receptor usage between different individuals

Blood ◽  
2008 ◽  
Vol 111 (4) ◽  
pp. 2053-2061 ◽  
Author(s):  
Laura Crompton ◽  
Naeem Khan ◽  
Rajiv Khanna ◽  
Laxman Nayak ◽  
Paul A. H. Moss
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Cell Response ◽  
Cd4 T Cells ◽  
Clonal Selection ◽  
Cell Receptor ◽  
T Cell Response ◽  
Cd4 T Cell ◽  
Extreme Conservation

Antigen-specific CD8+ cytotoxic T cells often demonstrate extreme conservation of T-cell receptor (TCR) usage between different individuals, but similar characteristics have not been documented for CD4+ T cells. CD4+ T cells predominantly have a helper immune role, but a cytotoxic CD4+ T-cell subset has been characterized, and we have studied the cytotoxic CD4+ T-cell response to a peptide from human cytomegalovirus glycoprotein B presented through HLA-DRB*0701. We show that this peptide elicits a cytotoxic CD4+ T-cell response that averages 3.6% of the total CD4+ T-cell repertoire of cytomegalovirus-seropositive donors. Moreover, CD4+ cytotoxic T-cell clones isolated from different individuals exhibit extensive conservation of TCR usage, which indicates strong T-cell clonal selection for peptide recognition. Remarkably, this TCR sequence was recently reported in more than 50% of cases of CD4+ T-cell large granular lymphocytosis. Immunodominance of cytotoxic CD4+ T cells thus parallels that of CD8+ subsets and suggests that cytotoxic effector function is critical to the development of T-cell clonal selection, possibly from immune competition secondary to lysis of antigen-presenting cells. In addition, these TCR sequences are highly homologous to those observed in HLA-DR7+ patients with CD4+ T-cell large granular lymphocytosis and implicate cytomegalovirus as a likely antigenic stimulus for this disorder.

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