Experimental Therapy of Paracoccidioidomycosis Using P10-Primed Monocyte-Derived Dendritic Cells Isolated From Infected Mice.

Paracoccidioidomycosis (PCM) is an endemic mycosis in Latin American caused by the thermodimorphic fungi of the genus Paracoccidioides spp. Notably, a Th1 immune response is required to control PCM. In this context, dendritic cells (DCs) seem to be essential players in capture, processing and presentation of Paracoccidioides antigens to naïve T cells and their further activation. We have previously demonstrated that differentiated DCs from bone marrow cells, pulsed with the immunoprotective peptide 10 (P10), effectively control experimental PCM immunocompetent and immunosuppressed mice. However, this procedure may not be infeasible or it is limited for the therapy of human patients. Therefore, we have sought a less invasive but equally effective approach that would better mimics the autologous transplant of DC in a human patient. Here, we isolated and generated monocyte differentiated dendritic cells (MoDCs) from infected mice, pulsed them with P-10, and used them in the therapy of PCM in syngeneic mice. Similar to the results using BMDCs, the P10-pulsed MoDCs stimulated the proliferation of CD4+ T lymphocytes, induced a mixed production of Th1/Th2 cytokines and decreased the fungal burden in murine lungs in the setting of PCM. The process of differentiating MoDCs derived from an infected host, and subsequently used for therapy of PCM is much simpler than that for obtaining BMDCs, and represents a more reasonable approach to treat patients infected with Paracoccidioides. The results presented suggest that P10-primed MoDC may be a promising strategy to combat complicated PCM as well as to significantly shorten the lengthy requirements for treatment of patients with this fungal disease.

Dendritic Cells Primed with Paracoccidioides brasiliensis Peptide P10 Are Therapeutic in Immunosuppressed Mice with Paracoccidioidomycosis.

Paracoccidioidomycosis (PCM) is an endemic systemic mycosis in Latin America, with the highest prevalence in Brazil, Colombia, and Venezuela. Fungi of the Paracoccidioides genus are etiologic agents of the disease. The 15 amino acid peptide P10 is derived from gp43, the main diagnostic antigen of Paracoccidioides brasiliensis. We previously reported that P10-pulsed dendritic cells (DCs) induce a protective response against P. brasiliensis. Presently, dexamethasone-treated BALB/c mice were intratracheally infected with P. brasiliensis Pb18 to establish the therapeutic efficacy of P10-pulsed DCs. Immunosuppressed and infected animals that received DCs had a reduction in their fungal burden, and this result was most pronounced in mice receiving DCs primed with P10. The efficacy of therapeutic DCs was significantly augmented by concomitant treatment with trimethoprim-sulfamethoxazole. Additionally, primed-DCs with or without the antifungal drug induced a beneficial Th1-biased immune response and significantly reduced tissue damage. In conclusion, these studies with immunocompromised mice demonstrate that P10-pulsed DCs with or without concomitant antifungal drugs are potently effective in combating invasive PCM. These findings support further translational studies to validate the use of P10-primed DCs for PCM in immunocompetent and immunosuppressed hosts.

Peptidorhamnomannan negatively modulates the immune response in a scedosporiosis murine model.

In this study, we analyzed the impact of immunization with the peptidorhamnomannan (PRM) from the cell wall of the fungus Scedosporium (Lomentospora) prolificans in a murine model of invasive scedosporiosis. Immunization with PRM decreased the survival of mice infected with S. prolificans. Immunization of mice with PRM led to decreased secretion of pro-inflammatory cytokines and chemokines but did not affect the secretion of IL-10. Mice immunized with PRM showed an increase in IgG1 secretion, which is an immunoglobulin linked to a nonprotective response. Splenocytes isolated from mice infected with S. prolificans and immunized with PRM showed no differences in the percentages of Th17 cells and no increase in the frequency of the CD4(+)CD62L(Low) T cell population. PRM-immunized mice showed a significant increase in the percentage of Treg cells. In summary, our results indicated that immunization with PRM did not assist or improve the immunological response against S. prolificans infection. PRM exacerbated the infection process by reducing the inflammatory response, thereby facilitating colonization, virulence and dissemination by the fungus.