title: Immunological aspects of Giardia infections.
abstract: Immunodeficiency, particularly antibody deficiency, predisposes to increased intensity and persistence of Giardia infections. Giardia-infected immunocompetent hosts produce serum and intestinal antibodies against Giardia trophozoites. The number of Giardia muris trophozoites, in mice with G. muris infection, is reduced by intra-duodenal administration of anti-G. muris antibody. Giardia intestinalis antigens that are recognised by human anti-trophozoite antibodies include variable (variant-specific) and invariant proteins. Nitric oxide (NO) appears to contribute to host clearance of Giardia trophozoites. Arginine is a precursor of NO and is metabolised by Giardia trophozoites, possibly reducing its availability for generation of NO by the host. Work with mice suggests that T lymphocytes and interleukin-6 (IL-6) contribute to clearance of Giardia infection via mechanisms independent of antibodies.
authors.affiliation: Research Service, Department of Veterans Affairs (VA) Medical Center, Philadelphia, PA 19104, USA - Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Martin F
authors.initials: MF
authors.lastname: Heyworth
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000096:biosynthesis / Q000276:immunology; D000953:Antigens, Protozoan / Q000276:immunology; D004195:Disease Models, Animal; D005872:Giardia / Q000276:immunology; D016829:Giardia lamblia / Q000254:growth & development / Q000276:immunology; D005873:Giardiasis / Q000276:immunology* / Q000517:prevention & control; D006790:Host-Parasite Interactions / Q000276:immunology; D006801:Humans; D007116:Immunization, Passive; D007121:Immunocompetence; D008565:Membrane Proteins / Q000276:immunology; D051379:Mice; D009569:Nitric Oxide / Q000502:physiology; D015800:Protozoan Proteins / Q000276:immunology; D013045:Species Specificity
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D008565:Membrane Proteins; D015800:Protozoan Proteins; C103927:Vsp protein, Giardia intestinalis; D009569:Nitric Oxide