Adjuvant effect of interleukin-1 on the development of late asthmatic response in guinea pigs

The adjuvant effect of silica and IL-1 in the development of late asthmatic responses (LARs) in guinea pigs was studied. Different doses of silica or recombinant human (rh) IL-1 (1 microgram) with Ascaris suum were used for the immunization. The serum IL-1 concentration was measured after the immunization. One week after the immunization, antigen was challenged and respiratory resistance (Rrs) was measured. Rrs increased silica dose dependently in the late phase, and the increment of Rrs in the late phase was significantly correlated with the serum IL-1 concentration (p < 0.05). In addition, rhIL-1 administration showed an increase in Rrs at the late phase. Antigen-specific IgE and IgG1 were also measured and were increased in guinea pigs immunized both with silica and rhIL-1.