Abstract
An immunostimulator agent was partially purified from the phenol-water extracts of M. bovis BCG by fractionation with Sepharose 6B and 4B columns. The agents showed multifold bioactivities, many of which are common to endotoxins. They are pyrogenicity, lethality in galactosamine-loaded mice, induction of tumor-necrosis-factor and interferons α/β in primed mice and immunoadjuvancy enhancing antibody production following in vivo administration, activation of the clotting enzyme cascade of the horseshoe crab, complement activation, and stimulatory effects on murine splenocytes and guinea-pig macrophages in in vitro assay. Although the chemical entity responsible for the above bioactivities has not yet been fully understood, chemical analysis revealed that the bioactive agent is polysaccharide (ca 92%), whose main component sugars are mannose and arabinose, connected with fatty acids (ca 10%), amino acids and amino sugars (ca 3.5% together), containing no detectable amounts of such constitutes characteristic of known immunomodulators of bacterial origin as LPS, cord factors, cell wall peptidoglycans, lipoteichoic acids and biologically active nucleic acids.
