Meeting Abstract

P2.51  Jan. 5  Immunosenescence in a long-lived Seabird CERCHIARA, J.A.*; ZANGMEISTER, J.L.; HAUSSMANN, M.F.; MAUCK, R.A.; Kenyon College; Kenyon College; Kenyon College; Kenyon College, Bowdoin College cerchiaraj@kenyon.edu

Life history theory predicts that long-lived species should invest heavily in maintenance systems affecting adult survival, however physiological systems deteriorate as a result of aging in most species. Immunosenescence is the decline in immune function with age. Previous research indicated immunosenescence of the cell-mediated branch of the acquired immune system in a long-lived seabird, Leach�s storm-petrel (Oceanodroma leucorhoa). We asked whether innate immune function also showed immunosenescence in the same population of Leach�s storm-petrels at the Bowdoin Scientific Station at Kent Island, N.B., Canada. We assessed bactericidal ability of whole blood to compare innate immune function of 9 individuals of at least twenty years of age to that of 81 individuals of unknown age. Old birds showed significantly decreased immune function compared to birds of unknown age (t = -3.062, p = 0.005). Bactericidal ability of storm-petrels was much less than other species we have measured (F = 74.448, p < 0.0001), suggesting that this species may encounter few novel pathogens and, therefore, does not require a strong innate immune system. Interestingly, innate immune function also decreased with incubation period (r = 0.185, p = 0.05), suggesting a trade-off between maintenance systems and reproduction. Given the decreased immune function in old birds, it may be that old breeders need to down-regulate maintenance systems, specifically immune function, more than younger breeders to achieve the same level of reproductive effort.