Humoral and cellular response in lambs vaccinated against Haemonchus contortus with p26/23

Antigen recognition patterns (Western blotting) and lymphoproliferative response (local and peripheral) have been determined in lambs immunised and partially protected against haemonchosis with p26/23, a purified somatic fraction of Haemonchus contortus. Immunoprotective response induced by p26/23 was accompanied by both specific lymphoproliferative response and serum antiHaemonchus antibodies. Western blotting showed an extensive reactivity of sera from p26/23 vaccinated lambs with peptides from adult soluble extract of the parasite at 23–26, 34–55, 55 and 65 kDa levels. Immunised lambs exhibited, after challenge, significantly higher lymphoproliferative responses (systemic and local) than all other animals groups (unvaccinated, adjuvant control animals, uninfected lambs). Challenge infection was accompanied by significant weight increases of abomasal lymph nodes; in addition specific peripheral and abomasal cell responses were correlated.