EXPRESSION OF T-CELL RECEPTOR-ALPHA AND BETA-VARIABLE GENES IN NORMAL AND MALIGNANT HUMAN T-CELLS

A PCR method was developed to analyse each of 29 families of the T cell receptor Valpha gene and 20 families of the Vbeta gene at the mRNA level in heterogenous cell populations. All Valpha and Vbeta families were detectable in blood mononuclear cells from four of six healthy donors. In two donors only Valpha22 was missing, and all other Valpha and Vbeta families were detected. Vbeta family expression was observed in T-leukaemic cell lines Jurkat, HSB, Molt-3 and Molt-4. In contrast, Valpha family expression was not detectable in any cell line except Jurkat cells. In T-cell malignancies (non-Hodgkin's lymphoma and mycosis fungoides), one or two Valpha and Vbeta families were detectable. Four of 10 cases investigated showed two Va transcripts and one Vbeta transcript. This fits with concepts in literature that allelic exclusion for the genes encoding alpha chains is not strictly required in the DNA rearrangement, or that this exclusion is a post-translational event. Using a limited series of antibodies to Vbeta gene family products, blood mononuclear cells from healthy donors were analysed by flow cytometry in a follow-up study. Two of four donors were rather stable in proportions of T cells expressing distinct Vbeta families, and two other donors showed variation in one or more families. When analysed on frozen tissue sections of normal lymph node and tonsil, there was no preferential location of lymphocytes expressing a distinct Vbeta gene family in different compartments (interfollicular area, follicle, or tonsillar epithelium).