[Effects of suplatast tosilate (IPD-1151T) on antibody formations in mice].

We examined the effects of suplatast tosilate (IPD-1151T) on antibody formation in mice, and the following results were obtained: 1) IPD-1151T clearly increased the productions of IgM and IgG-hemolytic plaque forming cells (PFC) in mice immunized with sheep red blood cells (SRBC) when the agent was given p.o. for 5 days from the day of immunization. 2) IgM and IgG-PFC productions in old mice, 60 weeks of age, were clearly lower than those in adult mice, 10 weeks of age; and an oral administration of IPD-1151T significantly recovered the decayed PFC-production in the old mice. 3) IPD-1151T clearly suppressed the production of anti-dinitrophenyl (DNP)-IgE antibody in mice when the agent was given p.o. for 5 days from the day of immunization, whereas the agent did not affect anti-DNP-IgM and IgG antibody productions. 4) IPD-1151T did not affect the induction phase of the cellular immune reaction of picryl chloride-induced contact dermatitis and the SRBC-induced footpad reaction. Our present results suggest that IPD-1151T has a class-specific suppressive effect on the production of IgE antibody, but does not suppress the other immune responses.