Abstract
Abstract Systemic lupus erythematosus (SLE) is a systemic autoimmune disease associated with significant morbidity and mortality. We have identified and characterized U1-70kDa small nuclear ribonucleoprotein (70kDa) autoantigen specific T cells in a murine model of autoimmunity when a subset of mice developed kidney disease similar to lupus nephritis. Mice developed proteinuria and histology showed CD4+ T cells associated with glomerular lesions. CD4+ T cells were freshly isolated from kidney and spleen and cultured with autoantigen to generate short-term T cell lines. Following RNA extraction from cell lines and cDNA preparation, a PCR reaction was performed using primers for the TRBV subgroups. The product was purified and underwent cloning and sequencing. T cell epitope mapping revealed that the majority of T cells were directed against antigenic peptides residing within the RNA binding domain of 70KDa. We also found that TCR beta (TRB) V usage was highly restricted among 70kDa reactive T cells which selectively utilized TCR BV subgroups 1 and 8.3 in the kidney and 1,2, 6, 8.1, 8.2, and 8.3 in the spleen and the lung. The TRB third complementary-determining regions (CDR3) had conserved sequence motifs which were shared across different TRBV subgroups. When compared for homology, the TRBV and CDR3 regions used by both murine and human 70kDa-specific CD4+ T cells were highly similar including those CD4+ T cells found at two sites of inflammation; the kidney and lung. The NIH and Dept Veterans Affairs provided support for this work.