Thymocytes reacting with heterologous antibodies against GP 330 in autologous immune complex glomerulopathy (AICG) in the rat. The relation between susceptibility for AICG and anti-GP 330-binding thymocytes.

Autologous immune complex glomerulopathy (AICG) is induced by immunizing rats with a crude brushborder fraction of rat kidney tubules (Fx1A) or with the purified GP 330 antigen. In these animals, anti-brushborder antibodies develop, leading to subepithelial immune complexes along the glomerular capillary wall. In rats with AICG, thymocytes sensitized against Fx1A as well as thymocytes recognizing anti-Fx1A are present. These latter cells might play a role in the specific tolerance against the pathogenetic antigen GP 330. To substantiate this notion, immunofluorescence studies were performed in which the number of anti-GP 330 binding cells was quantified in thymus cell suspensions of rats with AICG, in control rats and in naive rats with different genetic background. It is shown that increased numbers of anti-GP 330-binding thymocytes in rats with AICG are associated with a decline in the serum anti-brushborder titer. Furthermore, it appears that the number of anti-GP 330-binding thymocytes in naive rats of the non-responder Brown Norway strain is significantly higher as compared to the PVG/c and Lewis strains, which are susceptible for AICG. The correlation between the numbers of anti-GP 330-binding thymocytes and the susceptibility for AICG suggests a role for these cells in maintaining the tolerance against the Fx1A (GP 330) antigen.