Effect of Vaccinations with Recombinant Fusion Proteins on Ancylostoma caninum Habitat Selection in the Canine Intestine

Abstract

Laboratory dogs were vaccinated subcutaneously with 3 different recombinant fusion proteins, each precipitated with alum or calcium phosphate. The vaccinated dogs were then challenged orally with 400 third-stage infective larvae (L3) of the canine hookworm, Ancylostoma caninum. The 3 A. caninum antigens selected were Ac-TMP, an adult-specific secreted tissue inhibitor of metalloproteases; Ac-AP, an adult-specific secreted factor Xa serine protease inhibitor anticoagulant; and Ac-ARR-1, a cathepsin D-like aspartic protease. Each of the 3 groups comprised 6 male beagles (8 +/- 1 wk of age). A fourth group comprised control dogs injected with alum. All of the dogs vaccinated with Ac-TMP or Ac-APR-1 exhibited a vigorous antigen-specific antibody response, whereas only a single dog vaccinated with Ac-AP developed an antibody response. Dogs with circulating antibody responses exhibited 4.5-18% reduction in the numbers of adult hookworms recovered from the small intestines at necropsy, relative to alum-injected dogs. In contrast, there was a concomitant increase in the number of adult hookworms recovered from the colon. The increase in colonic hookworms was as high as 500%, relative to alum-injected dogs. Female adult hookworms were more likely to migrate into the colon than were males. Anti-enzyme and anti-enzyme inhibitor antibodies correlated with an alteration in adult hookworm habitat selection in the canine gastroinntestinal tract.

Stage‐specific immune responses in human Necator americanus infection

“…The experiments were conducted according to a protocol approved by the GWU Animal Care and Use Committee. Ancylostoma caninum L3 and adult worms were obtained from purpose-bred, male beagles (Marshall Farms) maintained at the GWU Animal Research Facility as previously described (20). Adult worm ES products were prepared according to Carr and Pritchard (21) and stored in aliquots at -80 ° C. All antigen preparations used in cell cultures were passed through a 0·22 µ m low-protein binding syringe filter (Millipore) and the resulting protein concentration was determined by using the BCA protein assay kit (Pierce).…”

Antibodies against a secreted protein from hookworm larvae reduce the intensity of hookworm infection in humans and vaccinated laboratory animals

“…Blood was drawn at least once every 21 days, and serum was separated from cells by centrifugation. Each animal's specific antibody response was measured by an indirect ELISA, as described previously (26,27). Briefly, recombinant ASP-2 was coated onto microtiter plates at a concentration of 5 μg/ml.…”

Twenty-five-year research progress in hookworm excretory/secretory products

“…Interestingly, rAc-APR-1 vaccine in dogs decreased adult hookworm number obtained from the small intestine and increased the worm burden from the large intestine, an unusual hookworm habitat. This change in the habitat preference proposes that Ac-APR-1-induced antibodies hindered the blood-feeding in the small intestine and thus forced worms to migrate into a more favorable habitat [157]. Worm burdens significantly dropped in Ac-APRvaccinated hamsters challenged with a different hookworm species (N. americanus) L3 [28], suggesting that Ac-APR-1 might cross-protect against its orthologs from other hookworm species.…”