Contribution to the study of the structure of adjuvant active waxes D from mycobacteria: Isolation of a peptidoglycan

Adjuvant and immunostimulating activities (in the absence of freund's incomplete adjuvant) of chemically modified low molecular weight mycobacterial peptidoglycans

Relatively low molecular weight peptidoglycan fragments extracted from two strains of Mycobacterium tuberculosis var. hominis were chemically coupled with lauric acid. The fatty acid conjugates were compared with the native substances with respect to some immunopotentiating activities. In vitro, the mitogenic effect on murine spleen lymphocytes was significantly enhanced following conjugation. One of the lauric acid conjugates stimulated, upon intravenous administration in mice, the formation of antibody-producing cells in the spleen, while the native substance was devoid of such activity. In adjuvanticity tests performed in the guinea pig in the absence of mineral oil, the fatty acid conjugates generally exerted a higher adjuvant effect on antibody production or on delayed type hypersensitivity reactions than did the native preparations.

Hydrosoluble immunostimulants of bacterial and synthetic origins

The role of whole Mycobacteria, mycobacterial cell walls and waxes D as immunostimulants was well established many years ago. More recently three different research groups have shown that hydrosoluble components from mycobacterial and other bacterial origins were as active as waxes D or cell walls and were free of many side-effects. Studies concerning the relationship between structure and activity were achieved which led to the description of a small biologically active fragment and to a first series of synthetic compounds.

Isolation and properties of a macromolecular, water-soluble, immuno-adjuvant fraction from the cell wall of Mycobacterium smegmatis

Trypsin- and chymotrypsin-treated delipidated cell walls of Mycobacterium smegmatis were digested overnight with lysozyme. The water-soluble products thus obtained were filtered on a column of Sephadex G-50; the first peak, excluded from the column, has immunological adjuvant activity. The material of the excluded peak is obtained after lyophilization as a snow-white, fluffy material, soluble in water and insoluble in organic solvents. It behaves as a slightly polydisperse macromolecule in an ultracentrifuge, with an approximate molecular weight of 20,000. All the constituents of this material are typical bacterial cell-wall constituents; thus, the water-soluble adjuvant is considered to be an "oligomer" of the cell wall. When added to Freund's incomplete adjuvant with an antigen (e.g., ovalbumin) and injected into hind-foot pads of guinea pigs, this water-soluble adjuvant increases the amount of precipitating antibodies and induces hypersensitivity to ovalbumin and the biosynthesis of gamma(2)-type precipitating antibodies. The water-soluble material has a stronger adjuvant activity than equal amounts of whole bacteria, cell walls, or wax D, and seems to be the first well-defined, water-soluble, adjuvant-active fraction isolated from Mycobacteria.

Wax D from different bovine strains of Mycobacterium

Wax D(P), a peptido-glycolipid found in extracts of Mycobacterium tuberculosis var. hominis, was not found in extracts of three strains of still-grown M. tuberculosis var. bovis (BCG, Marmorek and Dupray). However, extracts from three other bovine strains (Behring, LA and BB) did yield waxes D(P), and these did not differ as to their molar ratios of alanine/glutamic acid/diaminopimelic acid from human waxes D(P).