Characterization of the human T cell receptor alpha-chain repertoire and demonstration of a genetic influence on V alpha usage.

Despite considerable knowledge of the determinants and profile of the T cell receptor (TCR) beta-chain repertoire, very little is known about the repertoire of the V alpha and J alpha segments of the TCR in man or mouse. We have used the anchored polymerase chain reaction (PCR) to analyze the human TCR alpha-chain repertoire at the mRNA level in peripheral blood lymphocytes. We find marked differences in the usage of individual V alpha segments. The V alpha repertoire is determined both by differences in the use of individual V alpha gene segments at the time of gene rearrangement and by genetic influences on the selection of the expressed V alpha repertoire, presumably during thymic maturation. Analysis of the J alpha repertoire shows non-random usage of individual J alpha segments but no obvious relationship to chromosomal position. We also report three new V alpha segments, three new J alpha segments and possible allelic variation in V alpha gene segments. Two unusual TCR alpha transcripts are described which add new information on the nature of TCR alpha transcript assembly.