Abstract
The importance of the cellular immune system for the development of T1DM in the LEW.1AR1-iddm rat was investigated by use of polyinosinic-polycytidylic acid (Poly I:C) and by adoptive transfer of concanavalin A (Con A) activated lymphocytes from diabetic LEW.1AR1-iddm rats and the coisogenic LEW.1AR1 background strain. Poly I:C treatment induced diabetes, characterized morphologically by a diffuse infiltration of the pancreas, in up to 20% of the animals of the coisogenic LEW.1AR1 background strain. It did not increase the diabetes incidence of 30% of the LEW.1AR1-iddm strain. In contrast Poly I:C treatment induced diabetes in up to 80% of the animals of the Mhc congenic LEW.1WR1 strain. Adoptive transfer of lymphocytes activated by the T-cell mitogen Con A from diabetic donors doubled the incidence of diabetes, characterized morphologically by a focal insulitis, in diabetes prone LEW.1AR1-iddm recipients. In contrast, animals of the LEW.1AR1 background strain did not develop diabetes after adoptive transfer. Moreover, adoptive transfer of Con A activated lymphocytes from LEW.1AR1 rats to LEW.1AR1-iddm rats with 30 or 60% diabetes incidence, significantly decreased the incidence of diabetes in LEW.1AR1-iddm rats with 60% diabetes incidence. The results show that autoreactive lymphocytes induce beta cell destruction in the LEW.1AR1-iddm rat, while the LEW.1AR1 background strain apparently contains regulatory potential, which is able to counteract the autoimmune response.
Acknowledgements
We gratefully acknowledge the skilful technical assistance of M. Meyer and S. Eghtessadi. H.W. was a graduate student in the Graduate Research Training Programme No. 705 funded by the Deutsche Forschungsgemeinschaft. This work has been supported by a grant from the Deutsche Forschungsgemeinschaft to A.J. and by the NIH grant 1R21AI55464-01 to S.L. and H.J.H.