Candida albicans up-regulates the Fas-L expression in liver Natural Killer and Natural Killer T cells

RENNA MS; FIGUEREDO CM

IMMUNOBIOLOGY.

ELSEVIER GMBH

Año: 2015

0171-2985

After Candida albicans arrival to the liver, the local production ofproinflammatory cytokines and the expanded intrahepatic lymphocytes (IHL) can beeither beneficial or detrimental to the host. Hereinwe explored the balance between protective inflammatory reaction and liverdamage, focusing our study on the contribution of TNF-a and Fas-Fas-L pathways in the hepatocellular apoptosis associated to C. albicans infection. A robust tissuereaction and a progressive increase of IL-1b, IL-6 and TNF-a were observed in infected animals. Blocking the biological activityof TNF-adid not modify the number of apoptotic cells observed in C. albicans infected animals. Fas-L molecule was up regulated on purified hepatic mononuclear cells and its expression progressed withthe infection. In the IHL compartment, the absolute number of Fas-L+ NK and NKTcells increased on days 1 and 3 of the infection. C. albicans was also able to up regulate Fas-L expression in normalliver NK and NKT cells after in vitrocontact. The innate receptor TLR2 was involved in this phenomenon. In theinterplay between host  factors andevasion strategies exploited by pathogens, the mechanism supported here couldrepresent an additional way that allows this fungus to circumvent protectiveimmune responses in the liver.