Parasite enzymes as a tool to investigate immune responses

Italo M. Cesari Isabelle Bouty Daniel Bout Belkisyolé Alarcón de Noya Johan Hoebeke About the authors

Abstract

Previous evidences reported by us and by other authors revealed the presence of IgG in sera of Schistosoma mansoni-infected patients to immunodominant antigens which are enzymes. Besides their immunological interest as possible inductors of protection, several of these enzume antigens might be also intersting markers of infection in antibody-detecting immunocapture assays which use the intrinsic catalytic property of these antigens. It was thus thought important to define some enzymatic and immunological characteristics of these molecules to better exploit their use as antigens. Four different enzymes from adult worms were partially characterized in their biochemical properties and susceptibility to react with antibodies of infected patients, namely alkaline phosphatase (AKP, Mg*+, pH 9.5), type I phosphodiesterase (PDE, pH 9.5), cysteine proteinase (CP, dithiothreitol, pH 5.5) and N-acetyl-ß-D-glucosaminidase (NAG, pH 5.5). The AKP and PDE are distinct tegumental membrane-bound enzymes whereas CP and NAG are soluble acid enzymes. Antibodies in infected human sera differed in their capacity to react with and to inhibit these enzyme antigens. Possibly, the specificity of the antibodies related to the extent of homology between the parasite and the host enzyme might be in part responsible for the above differences. The results are also discussed in view of the possible functional importance of these enzymes.

Schistosoma mansoni; antigenic enzymes; immunodiagnosis; alkaline phosphatase; type I phosphodiesterase; cysteine proteinase; N-acetyl-â-D-glucosaminidase


ABSTRACT

Parasite enzymes as a tool to investigate immune responses

Italo M. Cesari1

Isabelle Bouty2

Daniel Bout2

Belkisyolé Alarcón de Noya3

Johan Hoebeke4

Instituto Venezolano de Investigaciones Científicas, Laboratorio de Immunoparasitología, Caracas, Venezuela

UFR des Sciences Pharmaceutiques, INRA d'Immunologie Parasitaire, Unité de Recherche Université, France

Universidad Central de Venezuela, Instituto de Medicina Tropical, Laboratorio de Biohelmintiasis, Caracas, Venezuela

Université de Tours, Faculté de Médicine, Laboratoire des Protides des Liquides Biologiques, France

Previous evidences reported by us and by other authors revealed the presence of IgG in sera of Schistosoma mansoni-infected patients to immunodominant antigens which are enzymes. Besides their immunological interest as possible inductors of protection, several of these enzume antigens might be also intersting markers of infection in antibody-detecting immunocapture assays which use the intrinsic catalytic property of these antigens. It was thus thought important to define some enzymatic and immunological characteristics of these molecules to better exploit their use as antigens. Four different enzymes from adult worms were partially characterized in their biochemical properties and susceptibility to react with antibodies of infected patients, namely alkaline phosphatase (AKP, Mg*+, pH 9.5), type I phosphodiesterase (PDE, pH 9.5), cysteine proteinase (CP, dithiothreitol, pH 5.5) and N-acetyl-ß-D-glucosaminidase (NAG, pH 5.5). The AKP and PDE are distinct tegumental membrane-bound enzymes whereas CP and NAG are soluble acid enzymes. Antibodies in infected human sera differed in their capacity to react with and to inhibit these enzyme antigens. Possibly, the specificity of the antibodies related to the extent of homology between the parasite and the host enzyme might be in part responsible for the above differences. The results are also discussed in view of the possible functional importance of these enzymes.

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Publication Dates

  • Publication in this collection
    04 June 2009
  • Date of issue
    1992
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