We have used PCR to study the expression of T-cell antigen receptor 13 RNA containing particular variable region (V) elements from transcripts directly in the cells isolated from joints and lymph nodes of B1O.Q mice (H-2r) immunized with chicken type II collagen. Our data show that the T cells present in arthritic joints expressed only a few '$ transcripts -'2, -6, -7, -8.2, -9, -10, and -15. 6 and -8.2 were expressed predominantly (six out ofseven animals) while others were expressed at a relatively low level in different animals. In lymph node cells, transcripts for $j6, -8.2, and -9 were detected in four out of seven animals. The data indicate that in collageninduced arthritis there is a restrictive usage of TCR $ elements and that *6 and -8.2 are probably used preferentially.Collagen-induced arthritis (CIA) was first described by Trentham et al. (1) in 1977 and has subsequently been induced in mice and primates (2, 3). CIA ensues after immunization of susceptible strains of mice and rats with type II collagen in Freund's adjuvant (1, 2). The arthritic lesions in this model bear resemblance to some of the lesions of rheumatoid arthritis in man. Both the cellular and T-cell-dependent immune responses to type II collagen are critical for the pathogenesis of the disease (4).Susceptibility to the development of an autoimmune disorder has been found to have a distinct genetic basis, both in humans and in animal models of the disease. In mouse, induction of CIA is linked to the major histocompatibility complex (MHC) and has been mapped to the I-A subregion by using various recombinant strains, and it has been shown that only H-2 and H-2r haplotypes develop CIA after immunization with type II collagen (4, 5). In other haplotypes, immunization with heterologous type II collagen induces an autoantibody response but never progresses to the development of arthritis (6, 7). These results indicate that the induction of CIA is dependent on the activation of I-A-restricted self-type-II-collagen-reactive T cells. Furthermore, in another study, Seki et al. (8) have proposed that there is a synergistic effect between humoral and cell-mediated immunity on the induction and perpetuation of CIA.We have earlier reported that the T-cell antigen receptor (TCR) variable region 18 chain (Vs) genes apparently play a vital role in the susceptibility to the induction of CIA (9). We have also shown that inbred strains of mice with the susceptible MHC haplotype but with the genomic deletion of TCR Vp genes were resistant to the induction of arthritis, indicating that TCR Vp genes play an important, perhaps crucial, role in the pathogenesis of arthritis (10-12). In this communication, we report that the T cells present in arthriticjoint and draining lymph nodes (LNs) of mice express a restricted repertoire of TCR Vp genes.MATERIALS AND METHODS Mice. B10.Q mice (H-2q) were bred and maintained in the mouse colony at Mayo Clinic (Rochester, MN). Male mice (6 to 8 weeks old) were used in the present study. Age-and sex-matched mic...