Studies on immunosuppressive effects of 2-acetylaminofluorene and cyclophosphamide by antibody forming cell assay and ELISA

Abstract

The immunosuppressive effect of 2-acetylaminofluorene and cyclophosphamide(CP) were investigated using the antibody forming cell assay and ELISA. In this study, antibody forming cell assay and measurement of secreted IgM level were simultaneously done in order to elucidate the correlation between two asay. Direct addition of AAF to the culture medium resulted in the suppression of polyclonal antibody response to LPS in a dose-related fashion. The secreted antibody level induced by LPS was also reduced in a similar profile. Time course studies demonstrated that antibody forming cell and secreted IgM reached maximum at day 2 and then decreased up to day 4. Treatment of AAF also showed similar pattern but suppessed antibody forming cell and IgM throughout culture periods, when compared to naive control. In order to study effects of CP, a co-culture system of rat hepatocytes and mouse splenocytes were used. CP also showed a dose-related suppression of antibody response to LPS when it was metabolized by rat hepatocytes. CP in itself did not produce suppression of antibody response even at highest dose, 1 mM. The secreted antibody level induced by LPS was also reduced in a similar profile. These results demonstrated that there was a good correlation between AFC assay and ELISA, and suggested that ELISA is a good assay system to screen for immunotoxic chemicals with similar sensitivity of AFC assay.