Characterization of the antigens that induce the production of antibodies in mice immediately after infection with Angiostrongylus cantonensis.

Following the infection of mice (a non-permissive host) with Angiostrongylus cantonensis, the occurrence of parasite-specific antibodies in the serum was monitored during the first 5 weeks after infection by the Ouchterlony method and by an immunoblotting technique, with special reference to the antigens recognized by host IgG antibodies. Only the serum from infected mice 7 days postinfection formed a single, distinct precipitin line when tested on Ouchterlony plates against extracts of digestive organs, reproductive organs, and body wall from adult female worms. In each case the precipitin line fused totally with that formed between the serum from infected mice and one of the other organ extracts. When the serum from infected mice was used as a blotting antibody under both reducing and nonreducing conditions, specific bands with molecular weights in the range from 60,000 to greater than 200,000 daltons were developed with each organ extract, although molecular weights varied according to the organ from which the antigenic extract was prepared. Further analyses on Ouchterlony plates and by immunoelectrophoresis and comparison with the reactivity of serum from permissive rat hosts infected 35 days postinfection with the same parasite revealed that an additional reactivity, distinct from that in rats, predominantly occurred in the serum from infected mice.