Post-thymectomy autoimmune gastritis: fine specificity and pathogenicity of anti-H/K ATPase- reactive T cells

and I-A d restricted, and recognize distinct peptides from the H/K ATPase chain. One cell line secretes Th1 and the other Th2 cytokines, but both are equally potent in inducing gastri- tis with distinct profiles of cellular infiltration in nu/nu recipient animals. Neither of the cell lines induced disease in normal BALB/c recipients and transfer of disease to nu/nu recipi- ents was blocked by co-transfer of normal BALB/c spleen cells containing CD4 + CD25 + cells. Although CD4 + CD25 + T cells are thought to emigrate from the thymus after day 3 of life, they could be identified in LN of 2-day-old animals. The capacity of CD4 + CD25 + Tc ells to abro- gate the pathogenic activity in vivo of both activated Th1/Th2 lines strongly suggests that this suppressor T cell population may have a therapeutic role in other models of established autoimmunity. The availability of well-characterized lines of autoantigen-specific T cells should greatly facilitate the analysis of the mechanism of action and target of the CD4 + CD25 + immunoregulatory cells.