Analysis of T cell receptor Vβ usage in the autoimmune sialadenitis of non-obese diabetic (NOD) mice

The NOD mouse develops spontaneous autoimmune sialadenitis besides a well characterized T cell-mediated autoimmune insulitis. We used reverse transcriptase-polymerase chain reaction (RT-PCR) to analyse the repertoire of T cell receptor (TCR) V beta chain genes expressed in the isolated infiltrating cells from affected salivary glands. Immunohistochemical analysis showed that the vast majority of inflammatory infiltrates in the salivary glands were CD4(+)V beta 8(+) and CD4(+)V beta 6(+) T cells, whereas CD8(+) T cells and B220(+) B cells were fewer in number. Predominant expression of the V beta 8 and V beta 6 gene segment was detected in the infiltrating cells in the salivary glands very early, and age-related diversity of TCR V beta gene usage was observed. Single-strand conformation polymorphism (SSCP) analysis demonstrated a strikingly symmetrical distribution of expanded clones in the PCR products of the V beta 8 and V beta 6 gene in the cells infiltrating the salivary glands. Nucleotide sequencing of amplified TCR V beta cDNA revealed that T cell clonotypes had a high incidence of identical clones, indicating that the immune response in NOD sialadenitis is driven by common stimuli. These findings suggest that in spontaneous autoimmune sialadenitis of NOD mice, there may be a restricted usage of TCR V beta elements in the early stage of the autoimmune lesion to recognize self-antigen in organ-specific autoimmune sialadenitis.