We have determined the primary structure of the alpha/beta-antigen receptor of a lymphocytic choriomeningitis virus (LCMV)-specific cytotoxic T cell clone (P14). The beta chain of the T cell receptor is composed of V beta 8.1, D beta and J beta 2.4 gene segments while the alpha chain uses a member of the V alpha 2 family and J alpha TA31. Southern blot analysis of a panel of six other independent LCMV-specific cytotoxic T cell clones did not reveal any preferential usage of the V alpha 2 or V beta 8 gene families in the cytotoxic LCMV response. Additionally, we have isolated and sequenced cDNA clones derived from the non-functionally rearranged alpha allele of P14. This transcript is composed of a unique V alpha gene segment which belongs to a new V alpha gene family.