Functional antigens of Trichuris muris released during in vitro maintenance: their immunogenicity and partial purification.

The immunogenicity of the secretory exo-antigen (EXA) originating in the stichosome of Trichuris muris has been investigated. High levels of immunity to challenge were produced using EXA (100 micrograms) by subcutaneous administration. Vaccination with a range of doses of EXA in Freunds' Incomplete Adjuvant (FIA) showed a dose response; 1 microgram of EXA reduced the worm burden by 50% and doses of 10 micrograms or more reduced the worm burden by 80-90% at Day 9 post-infection. Worms recovered from vaccinated mice were significantly smaller than those from controls. A precipitin line identifiable with EXA was shown to immunize mice against T. muris challenge by vaccination. The protective antigen contained in EXA has been partially isolated using gel filtration, ion exchange filtration and isoelectric focusing and has been shown to be a protein of 30000 molecular weight having a pI of 6.8-7.3.