The immunity of sheep to trichostrongyle infestations following reduction of the circulating leucocyte count by oral administration of chlorambucil: A further study of the spring-rise phenomenon

Abstract

Extract

Soulsry and Owen (1965) reported preliminary experiments which demonstrated the effectiveness of an alkylating agent, chlorambucil, in suppressing certain immunological responses in sheep. Haemagglutination and complement fixation tests, using antigen prenared from third stage infective larvae of Haemonchus contortus, showed that in all of five treated animals the complement fixation and haemagglutination titres fell to values of one-half or less within three weeks of the commencement of chlorambucil treatment. In one of the experimental animals, previously maintained under conditions of non-reinfection, a marked rise in strongvloid egg count occurred which suggested the reactivation of previously inhibited larvae.