title: Effect of testosterone on T cell-mediated immunity in two species of Mediterranean lacertid lizards.
abstract: One of the primary assumptions of the immunocompetence handicap hypothesis is that testosterone has an immunosuppressive effect, but conflicting results have been reported in a variety of bird species concerning the effect of testosterone on the humoral and the T cell-mediated components of the immune system. The T cell-mediated component of the immune system is particularly important during the breeding season, because the likelihood of injury during sexual competition is high and T cell-mediated immunity is essential for healing wounds and resisting infection. In this study we examined the effect of experimentally increased levels of testosterone during breeding season on T cell-mediated immunity in male lizards of two Mediterranean lacertid species, Psammodromus algirus and Acanthodactylus erythrurus. The hormonal treatment significantly increased testosterone of the experimental individuals. T cell-mediated responses to phytohemagglutinin stimulation were significantly suppressed in testosterone-treated males of both species. Furthermore, there was a significant negative relationship between individual variability in T cell-mediated responsiveness and plasma testosterone concentration. The present study is the first to demonstrate testosterone-induced suppression of T cell-mediated immunity in lizards.
authors.affiliation: Laboratoire d'Ecologie, Université Pierre et Marie Curie, CNRS UMR 7625, 75252 Paris, France. josabel.belliure@uah.es
authors.forename: Josabel
authors.initials: J
authors.lastname: Belliure
authors.forename: Linda
authors.initials: L
authors.lastname: Smith
authors.forename: Gabriele
authors.initials: G
authors.lastname: Sorci
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D007111:Immunity, Cellular / Q000187:drug effects* / Q000276:immunology; D007121:Immunocompetence / Q000276:immunology; D008116:Lizards / Q000276:immunology*; D008297:Male; D010835:Phytohemagglutinins / Q000276:immunology; D011863:Radioimmunoassay; D012098:Reproduction / Q000502:physiology*; D013030:Spain; D013739:Testosterone / Q000097:blood / Q000494:pharmacology*
chemical_list: D010835:Phytohemagglutinins; D013739:Testosterone