Abstract
The addition of adjuvant (Bacillus Calmette-Guérin-cell wall skeleton; BCG-CWS) to the culture medium substantially increased the immune response of mouse spleen cells to immunization with heterologous erythrocytes and hapten-protein conjugate in vitro. Cell walls of mycobacteria, nocardia and corynebacteria and their cell wall constituents were used as adjuvants. In the present case, it was found that cell walls of mycobacteria, nocardia and corynebacteria markedly facilitated primary humoral response of mouse spleen cells to heterologous erythrocytes in vitro. The adjuvant effect of BCG-CWS was present only in the formation of 19 S antibody in both primary and secondary responses, but not in that of 7 S antibody in vitro. Primary antihapten response of mouse spleen cells against dinitrophenylated keyhole limpet hemocyanin (DNP-KLH) also succeeded when BCG-CWS was added to the culture medium, and it was found that BCG-CWS increased the helper activity of carrier specific helper T cells in vitro where a double chamber system, separated by a cell-impermeable nucleopore membrane, was used. This result suggested that BCG-CWS acts on T cells, resulting in the release of soluble factor(s) from T cells capable of exerting an adjuvant effect. Furthermore, mucopeptide moiety of BCG-CWS retained some adjuvant activity, but other cell wall constituents, such as mycolic acid, arabinose mycolate, and arabinogalactan, did not show any adjuvant effect in vitro. These results strongly imply that mucopeptide moiety of BCG-CWS plays an important role in the development of adjuvanticity.
