Temperature influence on Arctic charr (Salvelinus alpinus L.) antibody response to a cellular antigen

In order to elucidate the immune responses of Arctic charr in relation to t emperature, groups were acclimated to a moderate (9 degrees C) and a cold t emperature regime (4 degrees C), as well as subjected to a temperature decr ease (from 9 to 4 degrees C) immediately prior to an immunization with shee p red blood cells. The charr kept at 9 degrees C responded with increased p rimary and secondary antibody titres, as seen by direct haemagglutination, while fish at 4 degrees C, as well as the fish subjected to a temperature r eduction, displayed lower and lowest antibody titres, respectively, and onl y after a second immunization, It is concluded that Arctic charr can respon d to a cellular antigen with a humoral immune response typical for other te leosts, but that the immune response is delayed and diminished at low tempe ratures. This temperature-induced immune suppression is intensified if the fish have not been acclimated to cold water prior to immunization.