677 FREQUENCY AND T-CELL RECEPTOR (TCR) REPERTOIRE OF HEPATITIS C VIRUS (HCV)-SPECIFIC CD8 T-CELLS IN HCV-SERONEGATIVE INDIVIDUALS

The T-cell receptor (TCR) is a highly polymorphic surface receptor that allows T-cells to recognize antigenic peptides presented on the major histocompatibility complex (MHC). Changes in the TCR repertoire have been observed in several autoimmune conditions, and these changes are suggested to predispose autoimmunity. Multiple lines of evidence have implied an important role for T-cells in the pathogenesis of Systemic Sclerosis (SSc), a complex autoimmune disease. One of the major questions regarding the roles of T-cells is whether expansion and activation of T-cells observed in the diseases pathogenesis is (auto)antigen driven. To investigate the temporal TCR repertoire dynamics in SSc, we performed high-throughput sequencing of CD4+ and CD8+ TCRβ chains on longitudinal samples obtained from four SSc patients collected over a minimum of two years. Repertoire overlap analysis revealed that samples taken from the same individual over time shared a high number of TCRβ sequences, indicating a clear temporal persistence of the TCRβ repertoire in CD4+ as well as CD8+ T-cells. Moreover, the TCRβs that were found with a high frequency at one time point were also found with a high frequency at the other time points (even after almost four years), showing that frequencies of dominant TCRβs are largely consistent over time. We also show that TCRβ generation probability and observed TCR frequency are not related in SSc samples, showing that clonal expansion and persistence of TCRβs is caused by antigenic selection rather than convergent recombination. Moreover, we demonstrate that TCRβ diversity is lower in CD4+ and CD8+ T-cells from SSc patients compared to healthy memory T-cells, as SSc TCRβ repertoires are largely dominated by clonally expanded persistent TCRβ sequences. Lastly, using 'Grouping of Lymphocyte Interactions by Paratope Hotspots' (GLIPH2), we identify clusters of TCRβ sequences with homologous sequences that potentially recognize the same antigens and contain TCRβs that are persist in SSc patients. In conclusion, our results show that that CD4+ and CD8+ T-cells are highly persistent in SSc patients over time, and this persistence is likely a result from antigenic selection. Moreover, persistent TCRs form high similarity clusters with other (non-)persistent sequences, that potentially recognize the same epitopes. These data provide evidence for an (auto-)antigen driven expansion of CD4/CD8+ T-cells in SSc.

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In chronic infection, HIV gag-specific CD4+ T cell receptor diversity is higher than CD8+ T cell receptor diversity and is associated with less HIV quasispecies diversity

Journal of Virology ◽

10.1128/jvi.02380-20 ◽

2021 ◽

Author(s):

Mark A Pilkinton ◽

Wyatt J McDonnell ◽

Louise Barnett ◽

Abha Chopra ◽

Rama Gangula ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

T Cell Receptor ◽

Cd8 T Cells ◽

Cd8 T Cell ◽

Cell Receptor ◽

T Cell Response ◽

Cd4 T Cell ◽

Tcr Repertoire ◽

Tcr Diversity

Cellular immune responses to Gag correlate with improved HIV viral control. The full extent of cellular immune responses comprise both the number of epitopes recognized by CD4+ and CD8+ T cells, as well as the diversity of the T cell receptor (TCR) repertoire directed against each epitope. The optimal diversity of the responsive TCR repertoire is unclear. Therefore, we evaluated the TCR diversity of CD4+ and CD8+ T cells responding to HIV-1 Gag to determine if TCR diversity correlates with clinical or virologic metrics. Previous studies of TCR repertoires have been limited primarily to CD8+ T cell responses directed against a small number of well-characterized T cell epitopes restricted by specific human leucocyte antigens. We stimulated peripheral blood mononuclear cells from 21chronic HIV-infected individuals overnight with a pool of HIV-1 Gag peptides, followed by sorting of activated CD4+ and CD8+ T cells and TCR deep sequencing. We found Gag-reactive CD8+ T cells to be more oligoclonal, with a few dominant TCRs comprising the bulk of the repertoire, compared to the highly diverse TCR repertoires of Gag-reactive CD4+ T cells. HIV viral sequencing of the same donors revealed that high CD4+ T cell TCR diversity was strongly associated with lower HIV Gag genetic diversity. We conclude that the TCR repertoire of Gag-reactive CD4+ T helper cells display substantial diversity without a clearly dominant circulating TCR clonotype, in contrast to a hierarchy of dominant TCR clonotypes in the Gag-reactive CD8+ T cells, and may serve to limit HIV diversity during chronic infection. IMPORTANCE Human T cells recognize portions of viral proteins bound to host molecules (human leucocyte antigens) on the surface of infected cells. T cells recognize these foreign proteins through their T cell receptors (TCRs), which are formed by the assortment of several available V, D and J genes to create millions of combinations of unique TCRs. We measured the diversity of T cells responding to the HIV Gag protein. We found the CD8+ T cell response is primarily made up of a few dominant unique TCRs whereas the CD4+ T cell subset has a much more diverse repertoire of TCRs. We also found there was less change in the virus sequences in subjects with more diverse TCR repertoires. HIV has a high mutation rate, which allows it to evade the immune response. Our findings describe the characteristics of a virus-specific T cell response that may allow it to limit viral evolution.

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Characterization of liver T-cell receptor γδ+ T cells obtained from individuals chronically infected with hepatitis C virus (HCV): Evidence for these T cells playing a role in the liver pathology associated with HCV infections

Hepatology ◽

10.1053/jhep.2001.24269 ◽

2001 ◽

Vol 33 (5) ◽

pp. 1312-1320 ◽

Cited By ~ 54

Author(s):

C Tseng

Keyword(s):

T Cells ◽

Hepatitis C Virus ◽

Hepatitis C ◽

T Cell ◽

T Cell Receptor ◽

Γδ T Cells ◽

Cell Receptor ◽

Liver Pathology

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T cell receptor repertoire in polymyositis: clonal expansion of autoaggressive CD8+ T cells.

Journal of Experimental Medicine ◽

10.1084/jem.181.5.1863 ◽

1995 ◽

Vol 181 (5) ◽

pp. 1863-1868 ◽

Cited By ~ 100

Author(s):

A Bender ◽

N Ernst ◽

A Iglesias ◽

K Dornmair ◽

H Wekerle ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

T Cell Receptor ◽

Cd8 T Cells ◽

Muscle Fibers ◽

Cell Receptor ◽

Inverse Pcr ◽

Receptor Repertoire ◽

Tcr Repertoire ◽

Muscle Lesions

In polymyositis (PM), CD8+ T cell receptor (TCR) alpha/beta + cells invade and destroy major histocompatibility complex class I-positive muscle fibers. We combined polymerase chain reaction (PCR) and double-fluorescence immunocytochemistry to analyze the T cell receptor (TCR) repertoire expressed in muscle of PM patients. In patient 1, inverse PCR revealed a preferential usage of TCR V alpha 33.1, V beta 13.1, and V beta 5.1. Six of six TCR V alpha 33.1+ clones and five of seven V beta 13.1+ clones had identical nucleotide sequences. In contrast, the V beta 5.1+ TCRs were more heterogeneous. Similar results were obtained with an independent PCR method using primers specific for TCR V alpha 33, V beta 13, or V beta 5. No TCR sequences could be amplified from noninflammatory control muscle. Furthermore, none of the TCR sequences found in PM muscle could be detected in blood from the same patient or from a normal control subject. Immunohistochemistry confirmed that V beta 5.1 and V beta 13.1 were overrepresented in the muscle lesions of this patient. 32% of all CD8+ T cells were V beta 13.1+, and 16% were V beta 5.1+. However, approximately 60% of the CD8+ T cells that invaded muscle fibers were V beta 13.1+, whereas 10% were V beta 5.1+. In patient 2, 50% of the T cells were V beta 5.1+, and as in patient 1, these T cells were mainly located in interstitial areas. In patient 3, > 75% of the autoinvasive T cells stained with an anti-V beta 3 mAb. Sequence analysis of 15 PCR clones amplified with a V beta 3-specific primer showed that 9 (60%) sequences were identical. The results suggest that (a) a strikingly limited TCR repertoire is expressed in PM muscle; (b) there is a dissociation between the TCR usage of autoinvasive and interstitial T cells; and (c) the autoinvasive T cells are clonally expanded.

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