Alloreactive T cells represent a relatively large fraction of the T cell population compared with the fraction of T cells that are specific for other foreign Ag. Recent findings indicate that most alloreactive T cells recognize endogenous peptides in association with a non-self MHC product. In light of these observations, it is perhaps not surprising that previous studies of the size of the TCR-αβ repertoire among alloreactive cells showed that they express many different Vα and Vβ genes. To further access the extent of diversity among alloreactive cells, we examined VαJα combinatorial diversity in polyclonal populations of a BALB/c anti-BALB.B mixed lymphocyte response. A long term culture from naive mice contained a diverse repertoire of VαJα combinations that was similar to the diversity present among unstimulated splenic T cells. In contrast, long term cultures from hyperimmunized animals contained 'dominant' clones of T cells that expressed a restricted repertoire of VαJα combinations. Examination of the nucleotide sequences of these α-chains suggested that there was selective expansion of T cells with identical α-chains. In addition, T cells that express the same VαJα combination but different junctions were also identified. Consistent with previous results, the isolates from hyperimmune animals did not contain somatic mutations in the CDR3 region of the α-chains. Nevertheless, the results suggest that T cells may be subject to in vivo selection and clonal expansion analogous to the process of affinity maturation of Ig.
|Original language||English (US)|
|Number of pages||7|
|Journal||Journal of Immunology|
|State||Published - Jan 1 1992|
ASJC Scopus subject areas
- Immunology and Allergy