Analysis of Vβ4 T cell receptor CDR3 repertoire in BALB/c and (NZB×NZW)F1 mice

To examine the unique TCR repertoire in auto-immune-prone (NZB×NZW)F1 (B/WF1) mice, we analysed the Vβ4 CDR3 region of TCRβ chain in spleens of young (1 month old) and aged (6 month old) BALB/c and B/WF1 mice. Total RNA from spleens was used for cDNA synthesis and TCRVβ4 PCR products were cloned and sequenced. Young B/WF1 mice showed high frequency (38.5%) of anionic amino acid residues at position β100 in TCRVβ4 chain compared to that (19.0%) in young BALB/c mice. Aged BALB/c mice and B/WF1 mice showed increase of frequency (38.1 and 51.9%, respectively) of anionic residues at β100. These results indicate that Vβ4-T cells that have anionic residues at β100 in CDR3 region of TCRβ chain increase with age in normal mice. Auto-immune prone mice show high frequency of anionic residues at β100 in TCRVβ4 chain even at the age of 1 month. These T cells may interact with cationic self-antigen(s) and might contribute to the onset and/or the progression of systemic autoimmunity in concert with other genetic elements in B/WF1 mice.