Previous studies in which the H-2Kb-specific cytolytic T lymphocytes (CTL) receptor repertoires were compared for murine strains that express different Igh alleles (C.B-20 and BALB/c) indicated that Igh-linked genes affected the composition of the expressed CTL receptor repertoire. To confirm this genetic localization, and also to individually assess the contributions of Igh-V- and Igh-C-linked genes to CTL repertoire expression, the H-2Kb-specific responses of two Igh recombinant strains, BAB/14 (Igh-Va-Cb) and C.B/R3 (Igh-Vb-Ca), were analyzed. The results indicate that strains which share Igh-V (but not Igh-C) genes demonstrate significant repertoire similarities, whereas strains which share Igh-C (but not Igh-V) are no more similar than strains dissimilar throughout the Igh complex. These results are discussed in the context of the existence of a naturally occurring idiotypic network involving immunoglobulin and CTL receptors.