Different expression of T-cell receptor β-chain variable region genes in lymph nodes of lpr mice with different alleles of the major histocompatibility complex

In order to search for a possible role of abnormally proliferating T cells in developing autoimmune disease in lpr mice, and to define the difference of the T cells among various lpr-congeneic mice with different clinicopathological findings, the T-cell receptor (TcR) Vβ gene expression in the enlarged lymph nodes (LN) of C3H/HeJ-lpr/lpr (C3H-lpr), C57BL/6-lpr/lpr (B6-lpr) and MRL/Mp-lpr/lpr (MRL-lpr) mice was analysed. A RNA blot analysis using several Vβ-specific probes showed that the Vβ₃ gene, whose products are important for recognizing Mls(b/a), was used in B6-lpr and MRL-lpr with the Mls(b/b) but not in C3H-lpr with the Mls(b/a). The Vβ₅ gene, which is selectively related to I-E molecules, was predominantly used in B6-lpr(I-E^-) but not in C3H-lpr(I-E⁺) nor MRL-lpr(I-E⁺). Similarly, the V₁₂ gene was also expressed in B6-lpr but not in C3H-lpr. To compare in detail the Vβ repertoire among lpr mice with different major histocompatibility complex (MHC) backgrounds, the Vβ gene sequences in the cDNA libraries from LN cells of C3H-lpr were analysed, following the recent investigation of B6-lpr mice (Ohga et al., 1989). Eleven β-chain cDNA out of 32 β cDNA in B6-lpr and 24 β-chain cDNA out of 55 β cDNA in C3H-lpr were found to contain sequences with open reading frames that potentially encode functional TcR β-chain. The frequencies of the messages in the cDNA libraries from these mice were consistent with the RNA blot analysis using Vβ₃- and Vβ₅-specific probes. It was notable that 36% of the functional β-chain mRNA in B6-lpr and 50% of the β mRNA in C3H-lpr expressed the Vβ₈ gene family. When the TcR Vβ gene expression was compared between the LN cells in C3H-lpr, B6-lpr and MRL-lpr, as reported by Singer et al. (1986), the usage of Vβ genes other than the Vβ₈ gene family in B6-lpr (H-2^b) LN cells differed significantly from those in C3H-lpr (H-2(k)) and MRL-lpr(H-2(k)). The results presented here indicate that the usage of Vβ genes in heavily influenced by the genetic background of lpr mice, similar to normal mice, but with preferential usage of the Vβ₈ gene family as a common structural feature in lpr gene-induced cell populations.