Involvement of platelet activating factor, histamine and serotonin in acute lethal shock induced by Candida albicans water-soluble extracellular polysaccharide fraction (CAWS) in mice.

CAWS (Candida albicans water-soluble extracellular polysaccharide fraction) is a water-soluble extracellular mannoprotein-beta-glucan complex obtained from the culture supernatant following the culture of pathogenic Candida albicans in a completely synthetic medium. CAWS administered intraperitoneally induces vasculitis in mice, however, administered intravenously, it causes lethal shock. The acute lethal reaction to CAWS occurs within 1 h of intravenous administration, with the mice demonstrating anaphylactic shock-like symptoms including convulsion, diarrhea, and collapse. In this study, we analyzed the factors involved in this lethal effect. We examined physiologically active substances believed to be involved in anaphylactic shock, and found that the lethal effect of CAWS could be inhibited by blocking histamine, serotonin, and platelet activating factor (PAF) simultaneously, but by blocking only one. This finding strongly suggests that the acute lethal reaction to CAWS is a result of the simultaneous production of several physiologically active substances.