Agar gel diffusion tests using extracts from adults and larvae of Trichinella spiralis have revealed qualitatively different antigenic substances. When adult antigen was tested against sera from rabbits infected with this parasite, two bands of precipitate were observed while three formed against larval antigen. The variations in position and density, and the noncoalescence of the larval and adult bands suggest different antigen-antibody systems. Results of immunoelectrophoretic studies using the same antigens and antisera have given further evidence for the presence of qualitatively different adult and larval antibodies.
Materials and Methods. Rabbits weighing from 5 to 6 kg were fed infective Trichinella spiralis larvae, each animal receiving 5 doses of 10,000 larvae at intervals of 5 days for a 30-day period. Ten days after the last dose and every 7 days thereafter blood samples were obtained from the ear vein and the sera separated.