Suppression of expulsion of Aspiculuris tetraptera in hydrocortisone and methotrexate treated mice.

Hydrocortisone treated male and female mice, given a primary infection with Aspiculuris tetraptera, did not reject the worms during the third week of infection. Mice given hydrocortisone during the first week of infection had elevated worm burdens on day 10, suggesting that some worm loss was encountered during the anterior migration in control mice. Furthermore, this temporary period of treatment was sufficient totally to suppress rejection and to allow the parasite to persist until day 28. Methotrexate also significantly delayed rejection, but larval growth was retarded in treated mice. These results, it is suggested, add strength to the hypothesis that the loss of A. tetraptera in a primary infection in mice, is an immunological phenomenon.