Experimental asthma in guinea pigs sensitized with mites (Dermatophagoides farinae)

Guinea pigs were intraperitoneally immunized with 1, 10, 100 or 1,000 micrograms protein of an extract from mites (Dermatophagoides farinae) incorporated with aluminium hydroxide gel 3 times every 28 days. Ten days after the last injection, a bronchial provocation test was performed by the use of the mite extract. The group immunized with 1 microgram protein produced very low levels of IgE-, IgG1- and IgG2 antibodies, and did not show asthmatic response upon the challenge. Although the group immunized with 10 micrograms protein showed higher rates of asthmatic onset than other groups, the sera of this group contained lower levels of IgE antibodies than the group immunized with 100 or 1,000 micrograms protein. However, the sera of the group immunized with 10 micrograms protein showed higher ratios of IgE/IgG1, IgE/IgG2 and lower ratios of IgG1/IgG2 antibodies than the sera of the group immunized with 100 or 1,000 micrograms protein.