T cell receptor (TCR) beta-chain usage by HLA-DR1 alloreactive T cell lines was examined to determine whether common TCR gene segments were used preferentially. We have demonstrated previously that a DR1-specific, human renal allograft-derived T cell line and replicate, anti-DR1 mixed lymphocyte reactions (MLR), established from an unrelated responder/stimulator pair, were selected for T cells expressing V beta 8. In this report V beta 8+ beta-chains from these T cell lines were sequenced to assess clonality and determine the contribution made by the beta-chain junctional regions. All 11 V beta 8+ cDNA clones sequenced from the allograft-derived T cell lines used J beta 2.7 and C beta 2 and had identical junctions, indicating the presence of a predominant V beta 8+ clone. All seven V beta 8+ sequences from the first anti-DR1 MLR and eight of the nine fron the second also used J beta 2.7 and C beta 2 were identical to one another, indicating that a common V beta 8+ clone was selected in these replicate cultures. The sequences of the predominant V beta 8+ beta-chains from the allograft-derived T-cell line and the MLR differed by only 10 nucleotides and four amino acids at the VDJ beta junction. To determine the reproducibility of TCR V beta selection in responses to DR1, additional MLR were established by pairing three different DR1+ stimulators with the same responder. The TCR repertoires of the resulting DR1-specific cell lines were examined. A preference was seen for utilization for certain homologous TCR V beta segments. The data suggest that particular TCR V beta or V beta/J beta combinations may be selected in alloresponses as evidenced either utilization of highly similar beta-chains or homologous V beta segments.