Transgenic rearranged T cell receptor gene inhibits lymphadenopathy and accumulation of CD4-CD8-B220+ T cells in lpr/ lpr mice.
The lpr gene in homozygous form induces development of CD4-CD8-B220+ T cells and lymphadenopathy in MRL and C57BL/6 mice. Although the propensity for excessive production of T cells is related to an intrinsic T cell defect, a thymus is also required because neonatal thymectomy eliminates lymphadenopathy. Recent evidence suggests that excessive production and release of autoreactive T cells from the thymus of lpr/ lpr mice might lead to downregulation of CD4 and CD8 as a "fail safe" tolerance mechanism that occurs during late thymic or post-thymic development. To test this hypothesis, T cell receptor (TCR) transgenic mice that produce large numbers of immature thymocytes recognizing the H-2Db and male H-Y antigens were backcrossed with C57BL/6-lpr/ lpr mice and MRL-lpr/ lpr mice. It was predicted that Db male lpr/ lpr mice would produce large numbers of autoreactive T cells during early thymic development that would lead to an accelerated lymphoproliferative disease. In contrast, Db female lpr/ lpr mice would produce large numbers of Db H-Y-reactive T cells, but might not develop lymphadenopathy because the male H-Y antigen would not be present. Unexpectedly, there was complete elimination of lymphadenopathy in both male and female TCR transgenic lpr/ lpr mice. The elimination of lymphadenopathy was not due to a failure of thymic maturation since the thymus of H-2Db female lpr/ lpr mice contained nearly normal numbers of mature thymocytes. Elimination of lymphadenopathy was also not due to a lack of autoreactive T cells in the peripheral lymph nodes (LN) since there was an increased syngeneic mixed lymphocyte proliferative response of LNT cells from transgenic lpr/ lpr compared with +/+ mice in vitro. Hypergammaglobulinemia and autoantibody production in the transgenic lpr/ lpr was present at levels comparable with or higher than control nontransgenic lpr/ lpr mice, suggesting a dissociation of autoantibody production from the lymphoproliferative disease in the TCR transgenic mice. Conversely, the development of lymphadenopathy and production of CD4-CD8-B220+ T cells appear to be intimately linked, as both were completely eliminated in T cells expressing the transgenic TCR. We propose that lymphoproliferation and production of CD4-CD8-6B2+ T cells in lpr/ lpr mice is related to decreased expression of the TCR, and providing the T cells with a rearranged TCR transgene overcomes this defect.[1]References
- Transgenic rearranged T cell receptor gene inhibits lymphadenopathy and accumulation of CD4-CD8-B220+ T cells in lpr/lpr mice. Mountz, J.D., Zhou, T., Eldridge, J., Berry, K., Blüthmann, H. J. Exp. Med. (1990) [Pubmed]
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