Hookworms are blood-feeding intestinal parasites of mammalian hosts and are one of the major human ailments affecting approximately 600 million people worldwide. These parasites form an intimate association with the host and are able to avoid vigorous immune responses in many ways including skewing of the response phenotype to promote parasite survival and longevity. The primary interface between the parasite and the host is the excretory/
secretory component, a
complex mixture of
proteins,
carbohydrates, and
lipids secreted from the surface or oral openings of the parasite. The composition of this
complex mixture is for the most part unknown but is likely to contain
proteins important for the parasitic lifestyle and hence suitable as
drug or
vaccine targets. Using a strategy combining the traditional technology of one-dimensional SDS-PAGE and the newer fractionation technology of OFFGEL electrophoresis we identified 105
proteins from the excretory/secretory products of the blood-feeding stage of the dog hookworm, Ancylostoma caninum. Highly represented among the identified
proteins were
lectins, including three
C-type lectins and three
beta-galactoside-specific S-type
galectins, as well as a number of
proteases belonging to the three major classes found in nematodes, aspartic,
cysteine, and
metalloproteases. Interestingly 28% of the identified
proteins were homologous to activation-associated secreted
proteins, a family of
cysteine-rich secreted
proteins belonging to the
sterol carrier protein/Tpx-1/Ag5/PR-1/Sc-7 (TAPS) superfamily. Thirty-four of these
proteins were identified suggesting an important role in host-parasite interactions. Other
protein families identified included hyaluronidases,
lysozyme-like
proteins, and
transthyretin-like
proteins. This work identified a suite of
proteins important for the parasitic lifestyle and provides new insight into the biology of
hookworm infection.