Effect of mycobacterial water-soluble adjuvant (MAF3) on the immune response of guinea pigs to the hapten-carrier conjugates.

Abstract

To clarify the complex mechanisms of the immune responses, many adjuvants have been used as immunologic tools. A classical example of such materials is Freund's complete adjuvant (FCA). It is well known that the heat-killed tubercle bacilli in mineral oil are the most important constituents for the adjuvant activity of FCA. Recently, it has been demonstrated that the tubercle bacilli in FCA can be replaced with water-soluble fractions from mycobacteria (1, 7, 10-13) and other Gram-positive bacteria (8). These water-soluble fractions probably share common chemical constituents. MAF3, which was prepared from the delipidated cells of Mycobacterium tuberculosis strain Aoyama B by hydrogenolysis and gel filtration (10), was found to be one of such water-soluble components responsible for the adjuvant activity. Although adjuvant activity of MAF3 on the antibody response, especially of the IgG2 class, and on the induction of delayed-type hypersensitivity (DTH) reaction to ovalbumin (OA) have been observed in guinea pigs, its effect on the immune response to other types of antigens such as hapten-carrier conjugates are not fully investigated yet. In this paper, we describe the adjuvant effect of MAF3 on the antibody response and the induction of DTH reaction in guinea pigs immunized with 2, 4-dinitrophenyl (DNP)-conjugates, DNP-bovine serum albumin (BSA), DNP-dextran or DNP-guinea pig serum albumin (GPA) emulsified with Freund's incomplete adjuvant (FIA) which lacks mycobacterial components. Female Hartley/s guinea pigs, weighing about 300 to 500 g, were used in all experiments. BSA (fraction V, Seikagaku-Kogyo, Tokyo), OA ( •~ 5 crystalline, ICN Pharmaceuticals Inc., Ohio) and GPA (Cohn's fraction V from normal guinea