Adoptive transfer of experimental autoimmune thyroiditis (EAT) in guinea pigs: requirement for Ia-positive antigen-presenting cells for in vitro activation of effector T cells.

Lymph node T cells from guinea pigs sensitized in vivo with guinea pig thyroglobulin (GPTG) could transfer experimental autoimmune thyroiditis (EAT) to normal syngeneic recipients after in vitro culture with GPTG or GPTG-pulsed peritoneal exudate cells (PEC). Although EAT effector T cells have been shown previously to be Ia negative at the time of transfer, the addition of specific anti-Ia serum to the cultures inhibited effector cell activation. The inhibitory effect of anti-Ia on effector-T-cell activation was shown to be due to inhibition of the function of antigen-presenting PEC rather than to an effect on the sensitized T cell. Moreover, only Ia-positive PEC could present antigen in this system and Ia matching between the PEC and the T cell was required for effective T-cell activation. GPTG-pulsed Strain 2 (EAT susceptible) and Strain 13 (EAT resistant) PEC could both present antigen to T cells from 2 X 13 F1 guinea pigs although Strain 2 PEC were more effective, suggesting that defective antigen presentation by macrophages may at least partially explain the relative resistance to EAT of Strain 13 guinea pigs. These results indicate that interaction between Ia-positive PEC and sensitized T cells in vitro is necessary for the development of active effector T cells that can transfer EAT.