Studies on the immunity of albino mice toTrichuris murisSuppression of immunity by cortisone acetate

Abstract

SUMMARYCortisone acetate, given to mice on two days during a primary infection with the nematodeTrichuris muris, suppressed the development of acquired immunity to the parasite. The proportion of mice in which suppression occurred was greatest when the drug was given (at 2.5 mg per mouse) on days 14 and 15 of the infection. Suppression of the response prevented the elimination of larvae, which otherwise occurs during the third week, and allowed the parasite population to mature and survive for at least a further 3 weeks. Similar treatment given during a challenge infection in resistant mice prevented the elimination of the challenge larvae for 2 or 3 days only. Mice in which cortisone treatment had prevented the elimination of a primary infection were not only found to be fully susceptible to subsequent challenge, but showed no development of immunity to the challenge infection itself. This long-lasting suppression of the immune response toT. murisis discussed and the possibility of the induction of a specific immunological unresponsiveness to the parasite is considered.