Humoral immune response against Clostridium perfringens toxoids in Leukosis Bovine Enzootic virus seropositive Holando heifers

Abstract

Enzootic bovine leukosis is the main virosis that affects dairy cattle in Uruguay. The subclinical infection causes importants dysfunctions in the immune system impacting directly in the animal health. The aim of this study was to evaluate the immune response of Holstein heifers with positive serology against Leukosis bovine virus (BLV) when they were ordinary immunized against Clostridium perfringens. It was evaluated a seropositive group to BLV animals (n=29) and other seronegative group (n=19) during twelve months. The animals recived three immunizations with a commercial polyvalent vaccine against several Clostridios (days 0, 30, 173). Blood samples were taken in days 0, 30, 60, 90, 180 y 360 post vaccination and then the humoral immune response was analyzed through the use of the ELISA technique to quantify total antibodies against C. perfringens toxins alfa, beta and épsilon. Besides it was in vitro analyzed the amount of neutralizing antibodies against epsilon toxin using the reference technique, seroneutralization. The results demonstrated a low response of neutralizing antibodies to epsilon toxin by SN technique showing no correlation with the results obtained by the commercial ELISA kit. Total antibodies response evaluated using commercial ELISA Kit was variable according to the studied toxoid. No significant differences were found in the immune response against Clostridium perfringens vaccination between BLV seropositive and seronegative animals using the techniques mentioned. The commercial ELISA kit use to analyze the response to vaccination against Clostridiosis, must be discussed and analyzed according to the results of this work.