The isolation and partial characterization of a protective antigen from developing larvae of Ascaris suum.

An antigen (ACF antigen) obtained by in vitro cultivation of third-stage larvae of Ascaris suum to the fourth stage in defined medium induced significant protection in guinea pigs. The antigen was further characterized by ultrafiltration and gel filtration and was shown to be a single component by gel precipition and immunoelectrophoresis. It induced active cutaneous anaphylaxis in sensitized animals. The ACF antigen is estimated to contain about 79% protein and 22% carbohydrate and to have a molecular weight of approx 67,000.