title: Immunity to onchocerciasis: identification of a putatively immune population in a hyperendemic area of Ecuador.
abstract: The existence of immunity to Onchocerca volvulus (Ov) infection is suggested by the presence of uninfected persons in hyperendemic areas. A major barrier to the study of immunity has been the correct identification of putatively immune (PI) subjects. To identify a PI group in a hyperendemic area in Ecuador, clinical and epidemiologic information was combined with a polymerase chain reaction (PCR)-based assay identifying Ov DNA in skin snips and a recombinant antigen-based ELISA. Comparison of immune responses revealed that PI subjects had significantly lower levels of Ov-specific IgG, IgG subclasses, and IgE than infected (INF) subjects. Female subjects were significantly more likely to be PI than male subjects, and INF female subjects had significantly lower levels of Ov-specific IgG, IgG1, and IgG3 than INF male subjects. Thus, the use of molecular-based techniques has helped to define more precisely the PI state in onchocerciasis.
authors.affiliation: Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: L H
authors.initials: LH
authors.lastname: Elson
authors.forename: R H
authors.initials: RH
authors.lastname: Guderian
authors.forename: E
authors.initials: E
authors.lastname: Araujo
authors.forename: J E
authors.initials: JE
authors.lastname: Bradley
authors.forename: A
authors.initials: A
authors.lastname: Days
authors.forename: T B
authors.initials: TB
authors.lastname: Nutman
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D000909:Antibodies, Helminth / Q000276:immunology; D001483:Base Sequence; D004247:DNA; D004484:Ecuador / Q000453:epidemiology; D005260:Female; D006801:Humans; D007109:Immunity; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D017181:Onchocerca volvulus / Q000276:immunology; D009855:Onchocerciasis / Q000175:diagnosis / Q000453:epidemiology / Q000276:immunology*; D016133:Polymerase Chain Reaction; D044469:Racial Groups; D012737:Sex Factors
chemical_list: D000909:Antibodies, Helminth; D004247:DNA