Endotoxin and Polysaccharide Derivative Induced Enhanced Antibody Formation in Leukemia Virus Infected Mice

Abstract

Endotoxins constitute a major component of the cell walls of gram-negative bacteria and are ubiquitously found in many microbial species (2,3,12,15). The molecules have been studied in great detail over the last few decades in terms of their chemical, physiologic and pharmacologic activities (11,13,20). They are also known to be potent modulators of immune responses, either enhancing or suppressing a wide variety of antibody or cell mediated activities (18–20). Endotoxin containing bacterial products have also been used as antitumor agents, presumably because they enhance nonspecific antitumor responses (14,17,19). It is now recognized that the Coley serum used over 60 to 70 years ago had effects because of the presence of bacterial endotoxin components and other biologically active cell wall materials in the preparations. In this context it has once again become popular in some instances to use bacterial components in attempts to induce antitumor immunity. Some investigators believe that treatment of cancer patients with bacterial products might stimulate nonspecific resistance to a tumor by activation of macrophages or other nonspecific effectors of immunity. Alternatively, such bacterial components might induce the production of soluble mediators of immunity, including interleukins and interferons (20,21).