Clonal Focusing of Epitope-Specific CD8⁺T Lymphocytes in Rhesus Monkeys following Vaccination and Simian-Human Immunodeficiency Virus Challenge

Abstract

To afford the greatest possible immune protection, candidate human immunodeficiency virus (HIV) vaccines must generate diverse and long-lasting CD8؉ T lymphocyte responses. In the present study, we evaluate T-cell receptor V␤ (variable region beta) gene usage and a CDR3 (complementarity-determining region 3) sequence to assess the clonality of epitope-specific CD8 ؉ T lymphocytes generated in rhesus monkeys following vaccination and simian-human immunodeficiency virus (SHIV) challenge. We found that vaccine-elicited epitopespecific CD8؉ T lymphocytes have a clonal diversity comparable to those cells generated in response to SHIV infection. Moreover, we show that the clonal diversity of vaccine-elicited CD8 ؉ T-lymphocyte responses is dictated by the epitope sequence and is not affected by the mode of antigen delivery to the immune system. Clonal CD8؉ T-lymphocyte populations persisted following boosting with different vectors, and these clonal cell populations could be detected for as long as 4 years after SHIV challenge. Finally, we show that the breadth of these epitope-specific T lymphocytes transiently focuses in response to intense SHIV replication. These observations demonstrate the importance of the initial immune response to SHIV, induced by vaccination or generated during primary infection, in determining the clonal diversity of cell-mediated immune responses and highlight the focusing of this clonal diversity in the setting of high viral loads. Circumventing this restricted CD8 ؉ T-lymphocyte clonal diversity may present a significant challenge in the development of an effective HIV vaccine strategy.

Human T Cell Memory: A Dynamic View

“…The pivotal determinant for selection into memory appeared to be the level of functional TCR avidity; high avidity clones being preserved whilst low avidity clones were lost [37]. The same clonal-focussing effect has also been reported in persistent murine polyoma virus-infection [38], and in a simian SHIV vaccination-rechallenge model [39], and is likely to represent a generic phenomenon.…”

Lessons learned from natural infection: focusing on the design of protective T cell vaccines for HIV/AIDS

“…Structural features of TCR usage is the third variable influencing the quality of a protective T cell response [89]. Clonal competition for endogenously expressed antigen, peptide MHC class I (pMHCI) structural landscape, precursor frequency, avidity, and antigen load have all been shown to influence TCR selection and functional differences in signaling [90,91].…”

Clonal Repertoires of Virus-Specific CD8+ T Lymphocytes Are Shared in Mucosal and Systemic Compartments during Chronic Simian Immunodeficiency Virus Infection in Rhesus Monkeys

“…RNA extracted from 10 5 CD8 + T cells sorted by flow cytometry was reverse transcribed to cDNA, as previously described (28). cDNA derived from each sample was equally distributed into 48 individual PCR mixtures, each containing a sense TCRBV gene family-specific primer, an antisense TCRBC-specific primer (CbR), and TCRBC-specific TaqMan probe.…”

“…The specificity of each of the primer pairs was confirmed by gel electrophoresis and sequencing PCR products. The real-time PCR was carried out for 50 cycles on an MX4000 QPCR machine (Stratagene), as previously described (28).…”