Hookworm burden reductions in BALB/c mice vaccinated with recombinant Ancylostoma secreted proteins (ASPs) from Ancylostoma duodenale, Ancylostoma caninum and Necator americanus

Vaccination of mice with alum-precipitated recombinant Ancylostoma secreted protein-1 from the canine hookworm Ancylostoma caninum (Ac-ASP-1) results in protection against A. caninum larval challenge. Vaccine protection is ma nifested by host reductions in hookworm burden compared to control mice. Th e goal of this study was to determine whether ASP antigens cloned and expre ssed from different hookworm species will cross protect against A. caninum larval challenge. Cross-species protection against A. caninum challenge inf ections was observed with immunizations using recombinant ASP-1 from the hu man hookworms Ancylostoma duodenale and Necator americanus. However, the de gree of protection was proportional to the extent of amino acid sequence ho mology between the ASP immunogen used for vaccination and the Ac-ASP-1 prod uced by the challenge larval strain. Vaccine protection was noted to decrea se significantly as amino acid sequence homologies diverged 10% or more. It was also determined that Ac-ASP-2, a molecule cloned from A. caninum havin g 55% amino acid sequence homology to the C-terminus of Ac-ASP-1, did not e licit vaccine protection. These observations were partly reflected in the t iter of antibodies that recognize Ac-ASP-1. The studies reported here will help to design immunogenic peptide vaccines based on the sequence divergenc e of hookworm ASPs. (C) 2000 Elsevier Science Ltd. All rights reserved.