1991 Volume 22 Issue 4 Pages 507-522
In order to elucidate the immunosuppression induced by infection with Mycoplasma pneumoniae (M. pn), the effects of M. pn antigen on the humoral and cell-mediated immunity of mice were studied. Changes in humoral and cell-mediated immune response against diphtheria toxoid (DT) and sheep red blood cells (SRBC) in mice immunized with a mixture of M. pn and DT or a mixture of M. pn and SRBC were analyzed by enzyme-linked immunosorbent assay (ELISA), plaque-forming cell assay (PFCA), footpad reaction (FPR) and flow cytometric analysis. The titer of antibody against DT in mice immunized with the mixture of M. pn and DT were significantly lower, compared with that of mice immunized with DT alone. In mice immunized with the mixture of M. pn and SRBC, the number of antibody-producing cells in the spleen against SRBC were lower, and the reaction of delayed-type hypersensitivity also decreased than that of mice immunized with SRBC alone. However, the levels of the immune response directed against M. pn were not changed. Flow cytometric analysis demonstrated that the population of immunologically competent cells significantly changed in a mouse after infection with M. pn, suggesting that the fluctuation of these cell populations are involved in the immunosuppression in mice infected and immunized with M. pn.
