title: Resistance to reinfection in mice as a vaccine model for giardiasis.
abstract: Infection with Giardia is the most commonly diagnosed parasitic cause of diarrhea in the developed world, yet no vaccine exists for human use and a commercially available veterinary vaccine is of limited utility. We have used the adult C57BL/6 mouse model of infection with Giardia duodenalis to better understand immunity to secondary infections with this parasite. Mice were primed by infection with either the GS or WB strains of Giardia and treated with metronidazole on day 7-12 to eliminate the primary infections. Challenge infections on day 21 or day 60 after the primary infections resulted in ~50-fold fewer parasites at day 5 than were found in unprimed mice that only received the challenge infection. Resistance to challenge infections was also observed in B cell deficient µMT mice and when primed mice were challenged with parasites of a different strain. While primed mice developed IgA, mast cell, and T cell responses against the parasite, no specific responses correlated with protection against challenge infections. Together these data suggest that development of an effective vaccine for giardiasis should be feasible since strong immunity can be developed against reinfection in the adult mouse model. Moreover we show that antibody responses are not essential for a protective vaccine and that protection is not parasite strain-specific.
authors.affiliation: Department of Biology and Center for Infectious Disease; Georgetown University; Washington, DC USA.
authors.forename: Erqiu
authors.initials: E
authors.lastname: Li
authors.affiliation: Department of Biology and Center for Infectious Disease; Georgetown University; Washington, DC USA; State Key Laboratory of Genetic Engineering; School of Life Sciences; Fudan University; Shanghai, PR China.
authors.forename: Mingqiu
authors.initials: M
authors.lastname: Liu
authors.affiliation: Department of Biology and Center for Infectious Disease; Georgetown University; Washington, DC USA.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Singer
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000032:analysis; D004195:Disease Models, Animal; D060467:Disease Resistance; D005260:Female; D016829:Giardia lamblia / Q000276:immunology*; D005873:Giardiasis / Q000276:immunology*; D007070:Immunoglobulin A / Q000032:analysis; D008407:Mast Cells / Q000276:immunology; D008810:Mice, Inbred C57BL; D016052:Protozoan Vaccines / Q000008:administration & dosage / Q000276:immunology*; D012008:Recurrence; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D000913:Antibodies, Protozoan; D007070:Immunoglobulin A; D016052:Protozoan Vaccines
keywords: B cells; IgA; cytokine; giardia; mast cell; memory; mucosal immunity; vaccine