EVIDENCE FOR SELECTIVE IN-VIVO EXPANSION OF SYNOVIAL TISSUE-INFILTRATING CD4-LYMPHOCYTES ON THE BASIS OF CDR3 DIVERSITY( CD45RO+ T)

In this study we have analyzed the TCR V(alpha) and V(beta) regions at the DNA level in the CD4+CD45RO+ memory T cell population of synovial tissue infiltrating T lymphocytes of three rheumatoid arthritis (RA) patients and one patient with chronic arthritis. Cell lines of CD4+CD4 5RO+, CD4+CD45RO-, CD8+CD45RO+ and CD8+CD45RO- T lymphocyte population s were generated following FACS cell sorting of freshly isolated synov ial tissue mononuclear cell infiltrates (STMC) and of freshly isolated peripheral blood mononuclear cells (PBMC) of these patients. The phen otypic and molecular analyses have revealed the following. (i) The TCR repertoires of tissue infiltrating T lymphocytes in the various subse ts were extensive on the basis of TCR V gene family usage. (ii) Furthe rmore, each patient displayed individual specific TCR V gene expressio n patterns in the various STMC and PBMC derived T cell subsets. Howeve r, the majority of these arthritis patients manifested increased expre ssion of multiple TCR V gene families in the synovial tissue derived C D4+CD45RO+ T cell population when compared with the peripheral blood d erived CD4+CD45RO+ subset. Of these gene families, we found enhanced e xpression of the TCR V(alpha)7 and V(beta)11 gene segments in synovial tissue to be shared by all four patients analyzed. (iii) Nucleotide s equence analysis of the CDR3 regions of a number of TCR V regions in t he CD4+CD45RO+ T cell subsets has revealed that the CDR3 regions compr ised within synovial tissue derived TCR V regions differed from those found in peripheral blood derived TCR V regions. These differences in CDR3 diversity might be the consequence of a specific interaction with particular MHC - peptide complexes expressed at the site of inflammat ion. (iv) The CDR3 region analysis also showed individual specific ami no acid motifs within the N - D - N regions of all analyzed TCR V(beta ) genes derived from PBMC as well as STMC.