Immunocompetence in a long-lived ectothermic vertebrate is temperature dependent but shows no decline in older adults

1. Temperature affects nearly all aspects of the physiology of ectotherms, including their ability to mount an immune response. Typically, the ectothermic vertebrate immune system can respond over a wide range of temperatures, but there is a species-specific temperature at which responses are strongest, with impaired responses above and below this threshold. In long-lived ectotherms, aging could also influence the ability to respond to temperature changes as immunosenecence, the functional decrease in immune function with age, is widely reported. 2. This study examined the effects of the interaction between temperature and age on B cell function in a long-lived reptile, the red-eared slider turtle, Trachemys scripta. B cells in this species have previously been shown to have two main functions, phagocytosis and antibody production. 3. Adult turtles were trapped and blood samples taken. Because sliders grow throughout their lifetime, plastron length was used as a proxy for age. Leukocyt...