title: Markedly Elevated Antibody Responses in Wild versus Captive Spotted Hyenas Show that Environmental and Ecological Factors Are Important Modulators of Immunity.
abstract: Evolutionary processes have shaped the vertebrate immune system over time, but proximal mechanisms control the onset, duration, and intensity of immune responses. Based on testing of the hygiene hypothesis, it is now well known that microbial exposure is important for proper development and regulation of the immune system. However, few studies have examined the differences between wild animals in their natural environments, in which they are typically exposed to a wide array of potential pathogens, and their conspecifics living in captivity. Wild spotted hyenas (Crocuta crocuta) are regularly exposed to myriad pathogens, but there is little evidence of disease-induced mortality in wild hyena populations, suggesting that immune defenses are robust in this species. Here we assessed differences in immune defenses between wild spotted hyenas that inhabit their natural savanna environment and captive hyenas that inhabit a captive environment where pathogen control programs are implemented. Importantly, the captive population of spotted hyenas was derived directly from the wild population and has been in captivity for less than four generations. Our results show that wild hyenas have significantly higher serum antibody concentrations, including total IgG and IgM, natural antibodies, and autoantibodies than do captive hyenas; there was no difference in the bacterial killing capacity of sera collected from captive and wild hyenas. The striking differences in serum antibody concentrations observed here suggest that complementing traditional immunology studies, with comparative studies of wild animals in their natural environment may help to uncover links between environment and immune function, and facilitate progress towards answering immunological questions associated with the hygiene hypothesis.
authors.affiliation: Menzies Research Institute Tasmania, University of Tasmania, Hobart, TAS, Australia; Department of Zoology, Michigan State University, East Lansing, MI, United States of America; Interdisciplinary program in Ecology, Evolutionary Biology and Behavior, Michigan State University, East Lansing, MI, United States of America; Department of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia.
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Flies
authors.affiliation: Department of Microbiology and Molecular Genetics, National Food Safety and Toxicology Center, Michigan State University, East Lansing, MI, United States of America.
authors.forename: Linda S
authors.initials: LS
authors.lastname: Mansfield
authors.affiliation: Custom Monoclonals International Corp, West Sacramento, CA, United States of America.
authors.forename: Chris K
authors.initials: CK
authors.lastname: Grant
authors.affiliation: Department of Psychology, University of California, Berkeley, CA, United States of America.
authors.forename: Mary L
authors.initials: ML
authors.lastname: Weldele
authors.affiliation: Department of Zoology, Michigan State University, East Lansing, MI, United States of America; Interdisciplinary program in Ecology, Evolutionary Biology and Behavior, Michigan State University, East Lansing, MI, United States of America.
authors.forename: Kay E
authors.initials: KE
authors.lastname: Holekamp
mesh_terms: D000818:Animals; D000835:Animals, Wild / Q000276:immunology*; D000836:Animals, Zoo / Q000276:immunology*; D000906:Antibodies / Q000097:blood*; D000974:Antibodies, Antinuclear / Q000097:blood; D000917:Antibody Formation / Q000276:immunology*; D004463:Ecology; D004777:Environment; D004926:Escherichia coli / Q000276:immunology; D005260:Female; D006433:Hemocyanins / Q000276:immunology; D045968:Hyaenidae / Q000276:immunology*; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D007630:Kenya; D008297:Male; D011513:Proteus mirabilis / Q000276:immunology
chemical_list: D000906:Antibodies; D000974:Antibodies, Antinuclear; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D006433:Hemocyanins; C032808:keyhole-limpet hemocyanin