title: Molecular cloning and characterization of a nematode polyprotein antigen/allergen from the human and animal hookworm Ancylostoma ceylanicum.
abstract: Nematodes are unable to synthesize fatty acids de novo and must acquire them from the environment or host. It is hypothesized that two unique classes of fatty acid and retinol binding proteins that nematodes produce (fatty acid and retinol binding (FAR) and nematode polyprotein antigen/allergen (NPA)) are used to meet this need. A partial cDNA has been cloned corresponding to four subunits of a putative Ancylostoma ceylanicum NPA (AceNPA). The translated amino acid sequence of AceNPA shares sequence identity with similar proteins from Dictyocaulus viviparus, Ascaris suum, and Ostertagia ostertagi. Immunoblot experiments using a polyclonal anti-AceNPA IgG revealed proteins corresponding to the expected sizes of single, as well as two or three un-cleaved NPA subunits in adult excretory/secretory proteins and soluble adult worm extracts. Immunohistochemistry experiments localize AceNPA to the cuticle, pseudocoelomic space and testes suggesting a role in hookworm biology that is distinct from what has previously been defined for other hookworm lipid binding proteins. A single recombinant subunit of AceNPA (rAceNPAb) demonstrated binding in vitro to fluorescent fatty acids DAUDA, cis-parinaric acid, as well as retinol, at equilibrium dissociation constants in the low micromolar range. Further, in vitro data reveal that rAceNPAb binds fatty acids with chain lengths of C12-C22, with the greatest affinities for arachidonic, linoleic (C18), and eicosapentaenoic (C20) acids.
authors.affiliation: Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN, USA. Electronic address: kfairfax@purdue.edu.
authors.forename: Keke C
authors.initials: KC
authors.lastname: Fairfax
authors.affiliation: Infectious Diseases Section and Program in International Child Health, Department of Pediatrics, Yale School of Medicine, New Haven, CT, USA.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Harrison
authors.affiliation: Infectious Diseases Section and Program in International Child Health, Department of Pediatrics, Yale School of Medicine, New Haven, CT, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Cappello
mesh_terms: D000595:Amino Acid Sequence; D000722:Ancylostoma / Q000235:genetics* / Q000378:metabolism; D000724:Ancylostomiasis / Q000469:parasitology / Q000662:veterinary; D000818:Animals; D000947:Antigens, Helminth / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D006224:Cricetinae; D018076:DNA, Complementary / Q000235:genetics; D005227:Fatty Acids / Q000378:metabolism; D005260:Female; D015801:Helminth Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D016415:Sequence Alignment
chemical_list: D000947:Antigens, Helminth; D018076:DNA, Complementary; D005227:Fatty Acids; D015801:Helminth Proteins
keywords: Ancylostoma ceylanicum; Fatty acid; Nematodes