The generation of monoclonal antibodies in mice: influence of adjuvants onthe immune response, fusion efficiency and distress

The objective of this study was to find a reliable alternative to Freund's adjuvant in order to reduce the distress imposed on the animals without imp airing the fusion efficiency for immune-positive clones. For this purpose s everal commercially available adjuvants and adjuvant formulations represent ing different classes of molecules were compared. Humoral responses and ani mals' distress evaluated by clinical assessment and histopathological exami nations were investigated and compared to fusion efficiencies. In a first s et of experiments seven adjuvants were tested essentially to determine thei r potential to induce distress. Poly(A).poly(U) and GERBU were selected for further investigations due to their low overall toxicity. They were combin ed with five different antigens and compared to the classic Freund's adjuva nt system (CFA/IFA) and to control immunizations without adjuvant. The resu lts showed that adjuvants of very low toxicity could induce a high fusion e fficiency. According to a standardized immunization protocol, GERBU induced polyclonal titres similar to Freund's whereas animals treated with poly(A) .poly(U) did not attain titres higher than mice immunized with antigen in s aline. Poly(A).poly(U) however, exhibited the best fusion efficiency, Freun d and GERBU were slightly less efficient. Therefore poly(A).poly(U) and GER BU may serve as valuable alternatives to Freund's adjuvant for generating m onoclonal antibodies. Furthermore, these two adjuvants are very easy to use .