Meeting Abstract

116.5  Saturday, Jan. 7  Thermal performance of innate immunity in vertebrates STAHLSCHMIDT, Z/R*; BUTLER, M/W; ARDIA, D/R; DAVIES, S; DAVIS, J/R; GUILLETTE, L/J; JOHNSON, N; MCCORMICK, S/D; MCGRAW, K/J; DENARDO, D/F; Arizona State Univ; Arizona State Univ; Franklin and Marshall College; Arizona State Univ; Rhodes College; Medical Univ of S. Carolina; U.S. Geological Survey; Univ of Massachusetts; Arizona State Univ; Arizona State Univ zrs@dal.ca

Innate immunity is the chief mechanism of host defense for most taxa, and temperature is a ubiquitous environmental factor that may affect immunity because it profoundly influences a broad range of biological processes—from biochemical reactions to locomotor performance. Thus, we examined the temperature dependence of two components of innate immunity (natural antibody agglutination and complement-mediated lysis) in 13 species spanning the seven major vertebrate groups: Agnatha, Chondrichthyes, Osteichthyes, Amphibia, Reptilia, Aves, and Mammalia. We measured in vitro immune function of plasma at nine different temperatures (5 – 47°C) to generate thermal performance curves of immunity. By using analyses of variance and principal components analyses, we found that (1) ectotherms generally had higher lysis and agglutination titers than endotherms, (2) temperature affected lysis and agglutination titers in all species, and (3) the optimal temperature for innate immune function only occasionally matched preferred body temperature, actual body temperature, and/or the optimal temperature of other performance measures (e.g., growth rate) in most species. Our results suggest that innate immune function is strongest at or below vertebrates’ typical body temperature. In sum, we clarify the role of temperature in immune performance across vertebrate taxa, which is an understudied aspect of ecological immunology that may have implications related to global climate change.