The abundance of memory-like T cells depends on TCR/MHC interactions (P1442)

Abstract

Abstract To investigate impact of TCR transgenic chains in formation of activation surface phenotype of T lymphocytes, we have generated mouse strain expressing transgenic beta-chain of TCR 1D1 (belonging to Vbeta6 family) on genetical background B10.D2(R101). Genomic sequence encoding TCR 1D1 beta-chain was isolated from memory T-hybridoma specific to Kb molecule. In thymus of transgenic mice accumulation of CD4-CD8-CD3- T lymphocytes takes place on the rate exceeding by several times the number of these cells in wild type animals. In transgenic animals about 70-80% of peripheral T lymphocytes express Vbeta6, whereas the percent of these cells does not exceed 5-7% in wild type animals. The ratio of peripheral CD4 and CD8 T lymphocytes stayed unchanged in transgenic mice. The percent of T cells with naive phenotype CD44-CD62L+ was significantly increased, whereas the levels of effector memory CD44+CD62L- and central memory CD44+CD62L+ T lymphocytes were markedly decreased. T lymphocytes expressing endogenous beta-chains mostly had the phenotype of memory-like T cells. Expression of 1D1 beta-chain was associated with naïve phenotype and lowered MLR-responses. These results suggest that appearance of memory-like T cells depends on interactions between TCRs and endogenous MHC/peptide complexes, whereas abundances of naive and memory-like T cells are regulated by competition of naive T cells for restricted number of appropriate MHC/peptide complexes in lymphoid tissue.