title: Systemic and local antibody response in mice induced by a recombinant peptide fragment from Giardia lamblia variant surface protein (VSP) H7 produced by a Salmonella typhimurium vaccine strain.
abstract: Previous experimental infections of mice with the intestinal protozoan Giardia lamblia had revealed that antigenic variation of the parasite was associated with the major surface antigen, named variant surface protein (VSP). In the present study, a gene segment of the VSP (VSPH7) from the well-characterized G. lamblia clone GS/M-83-H7 was expressed in the live-attenuated Salmonella typhimurium vaccine strain LT2M1C. The recombinant vaccine was assessed for its potential to induce both a systemic and a local antibody response in mice. Peroral administration of the vaccine stimulated synthesis of serum IgG and intestinal IgA antibodies directed against Salmonella antigens as well as against VSPH7. With respect to the anti-VSPH7 antibody concentrations, vaccination of animals resulted in systemic and local antibody responses similar to those induced by experimental or natural infections of mice with G. lamblia clone GS/M-83-H7. Subclass specification of serum anti-VSPH7 IgG demonstrated THelper 2-cell dependent IgG1- and/or IgG2b-type antibody production. No significant THelper 1-cell dependent IgG2a-type anti-VSPH7 antibody production was detected in infected or in vaccinated animals. Taken together, these data indicate a strong intrinsic antigenicity of VSPH7, which stimulates a THelper 2-cell pathway of the murine immune system, independent of the route of antigen administration. Furthermore, the high immunostimulatory potential of the recombinant Salmonella/VSPH7 model vaccine suggests application of LT2M1C as an enteric biocarrier for the identification of putative new target vaccines in giardiasis.
authors.affiliation: Institute of Parasitology, University of Berne, Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: Stäger
authors.forename: B
authors.initials: B
authors.lastname: Gottstein
authors.forename: N
authors.initials: N
authors.lastname: Müller
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis; D000913:Antibodies, Protozoan / Q000096:biosynthesis*; D000953:Antigens, Protozoan / Q000235:genetics / Q000276:immunology*; D000954:Antigens, Surface / Q000235:genetics / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology; D001428:Bacterial Vaccines / Q000235:genetics / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D016829:Giardia lamblia / Q000235:genetics / Q000276:immunology*; D005873:Giardiasis / Q000517:prevention & control; D007070:Immunoglobulin A / Q000096:biosynthesis; D007421:Intestine, Small / Q000276:immunology; D051379:Mice; D008813:Mice, Inbred ICR; D010446:Peptide Fragments / Q000235:genetics / Q000276:immunology; D015800:Protozoan Proteins; D016052:Protozoan Vaccines / Q000235:genetics / Q000276:immunology*; D012486:Salmonella typhimurium / Q000235:genetics / Q000276:immunology; D014614:Vaccines, Synthetic / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D000954:Antigens, Surface; D001428:Bacterial Vaccines; D007070:Immunoglobulin A; D010446:Peptide Fragments; D015800:Protozoan Proteins; D016052:Protozoan Vaccines; D014614:Vaccines, Synthetic; C072464:variant surface protein H7, Giardia lamblia