Cell-mediated immune responses in mice infected with fonsecaea pedrosoi

Abstract

Time course of cellular and humoral immune responses in mice infected with Fonsecaea pedrosoi was investigated by using an antigen prepared from culture filtrate of this fungus. Mice were infected by intravenous injection with yeast-like cells of the fungus. Viable fungus was recovered from the brain of the infected mice until the 36th day after inoculation, and from the other organs examined until 14th to 16th day. Inflammatory lesions were observed in the brain, lung, heart, liver, spleen, kidney and intestine during the first 30 days after inoculation. Macrophage migration inhibition factor response in these mice was insignificant until 8 days after inoculation. A significant response was developed at day 10 and persisted until day 63. This response returned negative by 95 days after inoculation. Lymphocyte transformation response of these mice was negative until 4 days after inoculation. At day 6 blastogenic index increased to 1.5, and at day 10, 14 and 16 the indices were 1.8, 2.4 and 1.7 respectively. Precipitin response to this fungus could not be detected in these mice until 16 days after inoculation, Positive results were obtained at day 21 and lasted until 51 days after inoculation. The precipitin titers, however, did not exceed one fold in any of these mice.

Prolonged infection byFonsecaea pedrosoiafter antigenic co-stimulation at different sites in experimental murine chromoblastomycosis

“…18,19,25,26 However, inoculation of viable cells from a CBM agent at different peritoneal sites in mice allows increased fungal persistence. [27][28][29] Following studies that showed increased host susceptibility to F. pedrosoi, we have become interested in inflammatory response at one infectious site (footpad) depends on the elimination of the antigenic stimulus at another site (peritoneum).…”

Chromoblastomycosis

“…Stimulation of CD4 ϩ cells by macrophages responsible for the engulfment of F. pedrosoi is essential to prevent CBM development (228). Impairment of cell-mediated immunity in CBM patients led to an inefficient reaction to fungally derived antigens, resulting in the maintenance of CBM-related fungi in lesional skin (229).…”

Black Yeasts and Their Filamentous Relatives: Principles of Pathogenesis and Host Defense

“…Both in vitro and preclinical studies focusing on fungus-host interaction indicate that cell-mediated immunity, and in particular activation of helper T cells by macrophages involved in fungal phagocytosis, plays a crucial role in prevention of disease caused by black yeasts (111,112).…”