[Effect of platinum and zirconium on IgM immune response in vitro].

In mouse spleen cells, the effects of chloroplatinic acid and zirconium oxychloride on IgM antibody production against sheep red blood cells (SRBC) were studied in vitro. The following conclusion were drawn from this study: 1. Chloroplatinic acid suppressed direct plaque formation against SRBC in mouse spleen cells in vitro. 2. The viability of mouse spleen cells, to which chloroplatinic acid was added was higher than that of control when they were cultuerd in a CO2 incubator for 4 days. 3. Zirconium oxychloride enhanced direct plaque formation against SRBC in mouse spleen cells in vitro. 4. Direct plaque formation in mouse spleen cells blended with macrophages obtained from mice intraperitoneally injected with zirconium oxychloride for a week showed a larger increase in response than when there was no addition of Zr-sensitized macrophages. From these results, it is suggested that the suppressed IgM immune response resulting from the addition of chloroplatinic acid may due to activated suppressor T cells, and that the enhanced response brought about by adding zirconium oxychloride may depend upon activated macrophages.