Myelin basic protein-specific and TCR Vβ8.2-specific T-cell lines from TCR Vβ8.2 Transgenic mice utilize the same Vα and Vβ genes: Specificity associated with the VαCDR3-Jα region

Our analysis of TCR V gene usage in mice transgenic for the Vβ8.2 gene has demonstrated that T cells isolated from the spinal cord of these transgenic mice during active experimental autoimmune encephalomyelitis were significantly biased for Vα2 expression. This Vα2 bias was noted in T cells derived from the periphery as well but only after stimulation with specific antigen. Thus, spinal cord-derived pathogenic T cells had already undergone activation and expansion within the central nervous system environment of these mice. As part of an investigation of regulatory function in these Vβ8.2 transgenic mice, two T cell lines were selected. The first T cell line is encephalitogenic and specific for the dominant myelin basic protein peptide NAc1-11, while the second T cell line is specific for the Vβ8.2 protein. Surprisingly, polymerase chain reaction and sequence analysis of the TCR from both T cell lines demonstrated that they utilize identical Vβ, Dβ, Jβ, and Vα gene segments. The only difference found was in their use of the Jα gene segment, indicating that this region of the TCR molecule can play a key role in determining antigen specificity.