IN-VIVO CYTOKINE GENE-EXPRESSION IN VARIOUS T-CELL SUBSETS OF THE AUTOIMMUNE MRL MP-LPR/LPR MOUSE/

We have used the reverse transcriptase polymerase chain reaction (RT-P CR) technique to assess the expression of cytokine genes in various T cell subsets of autoimmune-prone mice. Our study confirmed the previou sly described features in lpr mice that IFN-gamma, TNF-alpha, and TNF- beta were transcribed by various T cell subsets. We in this study demo nstrated that double negative (DN) T cells, the major cell population in lpr mice, failed to express interleukin-3 (IL-3), IL-4 IL-5, and IL -6 genes that influence B cell growth and activation. In contrast, DN T cells expressed Eta-1 gene that is shown to augment polyclonal activ ation of B cells and immunoglobulin production. Thus, it is conceivabl e that T cell-derived B cell-stimulatory activities in MRL/lpr mice ca n be attributed to Eta-1, rather than IL-3, IL-4, IL-5 or IL-6. We als o demonstrated that CD4(+) T cells infiltrating into kidney tissues of MRL/lpr mice expressed various cytokine genes such as IL-1, IL-5, IL- 6, IFN-gamma, TNF-alpha, TNF-beta and TGF-beta.