Suppression of glomerular IgA deposition in ddY mice through periodic injections of lipopolysaccharides.

We investigated the role of lipopolysaccharides (LPS) in glomerular IgA deposition of ddY mice. The incidence of IgA deposition was lower in the LPS-injected mice at 10 and 13 months of age as compared with that of their age-matched controls (10 months, LPS 20% vs control 60%; 13 months, LPS 14% vs control 100%). Serum levels of IgA were lower in the LPS-injected mice than in the control mice. There were no appreciable differences in the percentage value of Thy-1+ cells, the ratio of Lyt-1+/Lyt-2+ cells, mitogenic responses, or IL-1 activities between the LPS-injected and the control mice. On the other hand, the IgA responses of spleen and Peyer's patch cells in the LPS-injected mice were lower than those observed in the control mice. These results suggest that the persistent use of LPS directly suppresses gut-associated lymphoreticular tissue (GALT), and that the lower IgA response in GALT induced by LPS causes suppression of glomerular IgA deposition in ddY mice.