Androgen control of immunocompetence in the male house finch, Carpodacus mexicanus Müller

Pierre Deviche, Luis Cortez

Research output: Contribution to journalArticle

54 Scopus citations

Abstract

The immunocompetence handicap (ICH) hypothesis predicts that elevated levels of the gonadal androgen testosterone (T) entail obligatory costs, such as immunosuppression, but evidence supporting this immunosuppressive influence is equivocal. To investigate this question, adult males house finches, Carpodacus mexicanus, were exposed to short days and chronically treated with T-filled (T males; N=10) or empty (C males; N=10) Silastic capsules. Testosterone administration increased plasma T levels and the size of the cloacal protuberance, an androgen-dependent secondary sexual characteristic. To study humoral immunity, finches received injections of sheep red blood cells (SRBC) and we measured circulating concentrations of antibodies to these cells with a hemagglutination test. All males produced antibodies following four SRBC injections at weekly intervals. Antibody titers in T and C males did not differ 5 days after the fourth injection, but were 59% lower in T than C males 2 weeks later. To study cell-mediated immunity, we measured the local inflammatory response to an injection of phytohemaglutinin (PHA). This response in T and C males was similar 1 day after PHA injection, but was 58% less in T than C males 2 days following the injection. Thus, T and C males mounted similar humoral and cell-mediated immune responses, but T treatment compromised maintenance of these responses. The results, demonstrating immunosuppressive effects of elevated T, are consistent with the ICH hypothesis.

Original languageEnglish (US)
Pages (from-to)1287-1295
Number of pages9
JournalJournal of Experimental Biology
Volume208
Issue number7
DOIs
StatePublished - Apr 2005

Keywords

  • Androgen
  • Cell-mediated immunity
  • Humoral immunity
  • Immunocompetence handicap hypothesis
  • Inflammation

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Physiology
  • Aquatic Science
  • Animal Science and Zoology
  • Molecular Biology
  • Insect Science

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