ABSTRACT
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.
Subject(s)
Candida albicans/pathogenicity , Histamine/physiology , Platelet Activating Factor/physiology , Polysaccharides/toxicity , Serotonin/physiology , Shock, Septic/etiology , Acute Disease , Animals , Capillary Permeability/drug effects , Epinephrine/pharmacology , Male , Mice , Mice, Inbred C3H , Mice, Inbred ICR , Vasculitis/etiologyABSTRACT
The intraperitoneal administration of CAWS (water-soluble extracellular polysaccharide fraction obtained from the culture supernatant of Candida albicans) to mice induces coronaritis similar to Kawasaki disease. We analyzed differences in the production of cytokines involved in the occurrence of coronary arteritis among mouse strains, C3H/HeN, C57BL/6, DBA/2 and CBA/J that were injected with CAWS at 4 mg/mouse for 5 consecutive days in the first week and the fifth week of administration. The incidence of arteritis was 100% in C57BL/6, C3H/HeN and DBA/2 mice, but only 10% in CBA/J mice. The coronary arteritis observed in DBA/2 mice was the most serious, with several mice expiring during the observation period. The CAWS-sensitive strains revealed increased levels of IL-6 and IFN-gamma during the course of a specific response to CAWS by spleen cells. In contrast, IL-10 levels were observed to increase markedly in CAWS-resistant CBA/J mice, but not the CAWS-sensitive strains. However, TNF-alpha levels were more elevated only in DBA/2 mice. The difference in disease development and cytokine production strongly suggests that the genetic background of the immune response to CAWS contributes to the occurrence of coronary arteritis.
Subject(s)
Arteritis/chemically induced , Candida albicans/chemistry , Coronary Vessels/drug effects , Polysaccharides/toxicity , Animals , Antibody Formation/immunology , Arteritis/immunology , Arteritis/pathology , Candida albicans/immunology , Coronary Vessels/immunology , Coronary Vessels/pathology , Cytokines/immunology , Disease Models, Animal , Enzyme-Linked Immunosorbent Assay , Injections, Intraperitoneal , Male , Mice , Mice, Inbred C3H , Mice, Inbred C57BL , Mice, Inbred CBA , Mice, Inbred DBA , Polysaccharides/immunology , Polysaccharides/isolation & purification , Species SpecificityABSTRACT
Candida albicans is a medically important fungus which induces a disseminated candidasis and candidemia in immunocompromised hosts, and releases a polysaccharide fraction into the blood. We recently found that C. albicans released a water-soluble polysaccharide fraction (CAWS) into synthetic medium and demonstrated that CAWS was mainly composed of a complex of mannan and beta-glucan. In the murine system, CAWS showed a lethality resembling anaphylactic shock when administered i.v., and induced coronary arteritis similar to Kawasaki Disease (KD) when given i.p. In the present study, we examined the biological activity of CAWS in the cell culture and found the following: i) CAWS slightly induced production of IFN-gamma and IL-6 by splenocytes at lower dose (ca. 10 micro g/ml), but at a higher dose strongly inhibited the proliferation of splenocytes induced by a B cell mitogen, lipopolysaccharide (LPS) and a T cell mitogen, concanavalin A. ii) The viability of these splenocytes monitored by propidium iodide staining was significantly reduced. iii) The addition of CAWS to a culture of monophage RAW264.7 cells significantly reduced cellular growth rate dose dependently. iv) The LPS-mediated synthesis of cytokines by RAW264.7 cells was significantly inhibited by CAWS. v) CAWS induced an aggregation of platelets in human platelet-rich plasma, and vi) CAWS inhibited the production of thrombomodulin by human umbilical endothelial cells and acted synergistically with TNF-alpha. Thus, CAWS strongly inhibited the cellular functions of leukocytes in vitro, partly through direct cytotoxicity. The enhanced production in injured cells of the vascular endothelium would be related to the local inflammatory response in the coronary artery.
