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

Fungal x host interactions in Chromoblastomycosis

“…Another important point is that oral immunization results in less footpad inflammation, with the same granulomatous reaction, 26 which corroborates our previous results demonstrating that conidia, but not sclerotic cells, are capable of downregulating costimulatory molecules on Langerhans cells, 25 likely resulting in less inflammation. Interestingly, CD4KO, CD8KO and IL-10KO all presented the same tissue pattern, with a granulomatous reaction and the presence of giant cells, indicating the high capacity of these black fungi to stimulate histiocytes.…”

“…Thus, we remain uncertain which fungal form is responsible for initiating the disease and Furthermore, CD8KO mice displayed more pronounced lesions than CD4KO, with no signs of healing after almost six months of follow-up. 26 These results are apparently inconsistent with recently published data demonstrating that the absence of CD4 + cells induces a more severe form of the disease, in comparison to CD8KO mice. 19 However, if we consider DTH responsible for more pronounced CBM lesions in CD8KO animals, the results would be consistent with less DTH response found in CD4KO mice.…”

“…Interestingly, CD4KO, CD8KO and IL-10KO all presented the same tissue pattern, with a granulomatous reaction and the presence of giant cells, indicating the high capacity of these black fungi to stimulate histiocytes. 26 Along these lines, we have induced giant cells quite similar to those found in vivo (Fig. 2) via the interaction of sclerotic cells generated in vitro 24 with mouse peritoneal macrophages.…”

“…25 Regarding this issue of virulence, Machado et al presented new data employing multiple-site inoculation of F. pedrosoi conidia in different mouse strains, as well as in some knockout mice. 26 They showed an equal increase in footpad volume after inoculation when viable or non-viable fungal cells were inoculated some days earlier into the peritoneum, indicating that delayed-type hypersensitivity (DTH) is involved in lesion maintenance in mice.…”

Immunological Intolerance and Tolerance by Antigenic Co-Stimulation

“…Thus, tolerance can be broken by an inflammatory response [9]. In last decades, tolerance and its broken have been studied in the context of non-self antigens, particularly in responses to pathogens [14] [15] [16] [17].…”