Proteomics Analysis of the Excretory/Secretory Component of the Blood-feeding Stage of the

Hookworms are blood-feeding intestinal parasites of mammalian hosts and are one of the major human ail-ments affecting 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 in-terface between the parasite and the host is the excreto-ry/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 pro-teins were lectins, including three C-type lectins and three -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 se-creted proteins, a family of cysteine-rich secreted pro-teins 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 iden-tified 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 hookwor