title: Adaptive immune response in symptomatic and asymptomatic enteric protozoal infection: evidence for a determining role of parasite genetic heterogeneity in host immunity to human giardiasis.
abstract: The genetic basis of the ultimate clinical outcomes of human giardiasis has been the subject of numerous investigations. We previously demonstrated roles for both host and parasite factors in determining the outcome of enteric infection in a murine model of Giardia duodenalis infection. In the current study, fecal and serum specimens from healthy controls and human subjects infected with the intestinal parasite G. duodenalis were assessed. Using a semi-nested PCR method, clinical isolates were genetically characterized based on the gdh and tpi loci, and the phylogenetic trees were constructed. Using a sandwich ELISA method, the serum levels of representative TH1and TH2cytokines were measured in infected human subjects and healthy controls. Here we showed that symptomatic human giardiasis was characterized by significantly elevated serum levels of the TH1cytokine IFN-γ compared to healthy controls, whereas asymptomatic human subjects and healthy controls had comparable levels of serum IFN-γ. Further analyses showed that human subjects infected with G. duodenalis genotype AI had significantly elevated levels of serum IFN-γ and IL-10, but not IL-5, whereas human subjects infected with AII had similar levels of those cytokines compared to healthy controls. These data demonstrate roles for both host and parasite factors in the determination of the outcome of enteric infections and may further broaden our understanding of host-parasite interaction during enteric protozoal infections.
authors.affiliation: Department of Medical Parasitology and Mycology, Kerman University of Medical Sciences, Kerman, Iran; Leishmaniasis Research Center, Kerman University of Medical Sciences, Kerman, Iran.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Babaei
authors.affiliation: Department of Medical Parasitology and Mycology, Kerman University of Medical Sciences, Kerman, Iran.
authors.forename: Najmeh
authors.initials: N
authors.lastname: Malihi
authors.affiliation: Department of Medical Parasitology and Mycology, Kerman University of Medical Sciences, Kerman, Iran.
authors.forename: Naser
authors.initials: N
authors.lastname: Zia-Ali
authors.affiliation: Department of Medical Parasitology and Mycology, Kerman University of Medical Sciences, Kerman, Iran; Leishmaniasis Research Center, Kerman University of Medical Sciences, Kerman, Iran.
authors.forename: Iraj
authors.initials: I
authors.lastname: Sharifi
authors.affiliation: Department of Medical Parasitology and Mycology, Kerman University of Medical Sciences, Kerman, Iran.
authors.forename: Mohammad A
authors.initials: MA
authors.lastname: Mohammadi
authors.affiliation: Laboratory of Mucosal Immunology, School of Medicine, University of California, La Jolla, CA, United States.
authors.forename: Martin F
authors.initials: MF
authors.lastname: Kagnoff
authors.affiliation: Laboratory of Mucosal Immunology, School of Medicine, University of California, La Jolla, CA, United States.
authors.forename: Lars
authors.initials: L
authors.lastname: Eckmann
authors.affiliation: Department of Biology and Center for Infectious Disease, Georgetown University, Washington, DC, United States.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Singer
authors.affiliation: Laboratory of Mucosal Immunology, School of Medicine, University of California, La Jolla, CA, United States; Vaccine Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States. Electronic address: shahram.sm@nih.gov.
authors.forename: Shahram
authors.initials: S
authors.lastname: Solaymani-Mohammadi
mesh_terms: D056704:Adaptive Immunity; D000293:Adolescent; D000328:Adult; D000818:Animals; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D016207:Cytokines / Q000097:blood; D016054:DNA, Protozoan / Q000235:genetics; D005243:Feces / Q000469:parasitology; D005260:Female; D018740:Genetic Heterogeneity; D005838:Genotype; D016829:Giardia lamblia / Q000235:genetics* / Q000276:immunology*; D005873:Giardiasis / Q000276:immunology* / Q000469:parasitology*; D006801:Humans; D008297:Male; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D018417:Th1 Cells / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology; D055815:Young Adult
chemical_list: D016207:Cytokines; D016054:DNA, Protozoan
keywords: Cytokines; Giardia duodenalis; Human; Protozoa