Mucosal antibody responses in experimental hookworm infection

SUMMARY Hookworms are bloodfeeding nematodes that reside in the intestinal mucosa. These parasites secrete proteins that induce robust systemic immune responses in humans and experimental animals. By contrast, mucosal immune responses in and around the site of attachment are not described as well. This paper presents data from studies aimed at examining hookworm-specific mucosal antibody responses in a hamster model of Ancylostoma ceylanicum infection. Intestinal flush prepared from infected hamsters was analysed by ELISA and shown to be enriched in IgA-specific for A. ceylanicum excretory–secretory (ES) products. Evaluation of mucosal IgA responses by immunoblot demonstrated that infected hamsters recognized a broad range of ES proteins. Hamsters repeatedly exposed to drug-terminated infections were shown to have enhanced serum IgG and mucosal IgA responses, as well as a high level of protection from challenge infection. Parasite-specific IgA was also detected in the faeces of hamsters undergoing a primary infection, and increasing faecal IgA responses were coincident with significant reductions in intestinal worm burdens and faecal ES output over time. Together these results suggest that secretory IgA may act in concert with other components of the mucosal and systemic immune response to promote protective immunity against hookworm infection and/or disease.