The worm extract (somatic antigen) and exsheathing fluid (“ES”antigen) derived from Anisakis larvae were tested and evaluated as antigen for detecting hypersensitivity in the infected mice. Heterologous antigens from Toxocara canis and Ascaris suum were also tested for comparison.
Mice were infected intraperitoneally each with 5 living Anisakis larvae. Subcutaneous air pouches were made on these mice at various intervals after infection and their spreads were studied for mast cell degranulation after injections of the antigens.
Anisakis antigens, both “ES” and somatic, produced more marked damages to the cells than the heterologous antigens. The host-tissue sensitivity to “ES” antigen appeared 10 days after infection with the larvae and persisted for at least 6 months, showing maximal rates of cell damage (97.7%) 2 months after infection.
The “ES” antigen produced much more intensive damages to the cells than the somatic antigen at both early and late stages in the course of infection, with the most conspicuous difference a month after infection.
In another test with mice infected with Ascaris suum eggs, Ascaris antigen gave more marked cell damages than Anisakis and Toxocara antigens.
Discussions were made in relation to the superiority of “ES” over somatic antigen in the skin test for human anisakiasis, particularly at an early stage of the infection.