Pesticide dichorvos induces early solid Ehrlich tumoral development associated with a non-protective pro-inflammatory response.

Prolonged exposure to dichlorvos (DDVP), a common pesticide used for food crops, has been related to the development of infections and malignancies. Macrophages are used as bioindicators of immunotoxicity; thus, evaluation of their activity in solid Ehrlich tumor-bearing mice (TBM) may be useful to evaluate the influence of pesticides on human health. To investigate the effects of low DDVP doses, Swiss mice were divided into the following groups: the DDVP group, composed of mice fed diets containing 10 mg/kg of DDVP; the TBM group, consisting of mice subcutaneously inoculated with 107 tumor cells/100 µl and fed a basal diet; the DDVP-TBM group, consisting of mice previously fed DDVP-containing diets for 28 days and then subcutaneously inoculated with tumor cells; and the control (CTRL) group, composed of mice fed a basal diet. After 7 and 21 days of tumor inoculation, the mice were euthanized; and after necroscopic examination, the neoplastic mass, organs, and intraperitoneal fluid were collected. Adherent peritoneal cells were cultivated to determine the production of H2O2 and TNF. Altogether, our results indicate that even at low doses, the intake of DDVP caused weight loss and increased tumor mass, which were associated with H2O2 production and high levels of TNF, a pro-inflammatory cytokine. These data are important as the exposure to pesticides, even at low doses, could potentially hinder the immune response against tumors and, consequently, create favorable conditions for their development.

Modulation of macrophage cytokine profiles during solid tumor progression: susceptibility to Candida albicans infection.

BACKGROUND: In order to attain a better understanding of the interactions between opportunist fungi and their hosts, we investigated the cytokine profile associated with the inflammatory response to Candida albicans infection in mice with solid Ehrlich tumors of different degrees. METHODS: Groups of eight animals were inoculated intraperitoneally with 5 x 106 C. albicans 7, 14 or 21 days after tumor implantation. After 24 or 72 hours, the animals were euthanized and intraperitoneal lavage fluid was collected. Peritoneal macrophages were cultivated and the levels of IFN-gamma, TNF-alpha, IL-12, IL-10 and IL-4 released into the supernatants were measured by ELISA. Kidney, liver and spleen samples were evaluated for fungal dissemination. Tumor-free animals and animals that had only been subjected to C. albicans infection were used as control groups. RESULTS: Our results demonstrated that the mice produced more IFN-gamma and TNF-alpha and less IL-10, and also exhibited fungal clearance, at the beginning of tumor evolution. With the tumor progression, this picture changed: IL-10 production increased and IFN-gamma and TNF-alpha release decreased; furthermore, there was extensive fungal dissemination. CONCLUSION: Our results indicate that solid tumors can affect the production of macrophage cytokines and, in consequence, affect host resistance to opportunistic infections.

Modulation of macrophage cytokine profiles during solid tumor progression: susceptibility to Candida albicans infection

Background: in order to attain a better understanding of the interactions between opportunist fungi and their hosts, we investigated the cytokine profile associated with the inflammatory response to Candida albicans infection in mice with solid Ehrlich tumors of different degrees. Methods: groups of eight animals were inoculated intraperitoneally with 5 × 106 C. albicans 7, 14 or 21 days after tumor implantation. After 24 or 72 hours, the animals were euthanized and intraperitoneal lavage fluid was collected. Peritoneal macrophages were cultivated and the levels of IFN-γ, TNF-α, IL-12, IL-10 and IL-4 released into the supernatants were measured by ELISA. Kidney, liver and spleen samples were evaluated for fungal dissemination. Tumor-free animals and animals that had only been subjected to C. albicans infection were used as control groups. Results: our results demonstrated that the mice produced more IFN-γ and TNF-α and less IL-10, and also exhibited fungal clearance, at the beginning of tumor evolution. With the tumor progression, this picture changed: IL-10 production increased and IFN-γ and TNF-α release decreased; furthermore, there was extensive fungal dissemination. Conclusion: our results indicate that solid tumors can affect the production of macrophage cytokines and, in consequence, affect host resistance to opportunistic infections(AU)

Eritema nodoso hansênico: análise comparativa do quadro histopatológico pelas técnicas de rotina e imunofluorescência / Erythema nodosum leprosum: comparative analysis of histopathologic situation by routine and immunofluorescence technique

Com a finalidade de investigar a participaçao dos imunocomplexos (Ic) na reaçao de Eritema Nodoso Hansênico (ENH), fragmentos teciduais de 22 pacientes hansenianos reacionais foram avaliados através da técníca de imunofluorescência direta (IFD) em associaçao com técnicas histopatológicas de rotina. Os resultados demonstraram a presença de Ic em vasos e zona de membrana basal da junçao dermo-epidérmica (ZMB). A presença de Ic em vasos do derma profundo e tecido celular subcutâneo em correspondência com alteraçoes vistas sob a forma de vasculites alterativas, exsudativas e necrotizantes sugerem envolvimento destes complexos no ENH.

Experimental paracoccidioidomycosis of hamster inoculated in the cheek pouch

We comparaed the granuloma morphology and immune response of hamsters inoculated with Paracoccidioides brasiliensis (Pb) into the cheek pouch, which lacks lymphatic drainage, and the ffotpad, which is rich in lymphatics. Our objective was to better understand the modulation of Pb granuloma in an immunocompetent animal inoculated in an immunologically privileged site. The humoral immune response (ELISA) and cell mediated immunity (footpad test) became positive on days 7 and 14, respectively in animal inoculated into footpad and on days 35 and 60 in animals inoculated into the pouch. Typical epithelioid granulomas were observed at both sites on day 14. The number of fungi gradually decreased from the beginning of the experiment in footpad lesions, but only after day 35 in pouch granulomas, when cell mediated immunity was detectable. The results indicate that typical epithelioid paracoccidioidomycotic granulomas may develop in the absence of a detectable immune response; however, they are incapable of controlling fungal reproduction. Lack of lymphatic drainage delays the appearance of a detectable immune response, but with time fungi escape from the pouch, elicit an immune response and reach other organs. Our results further indicate the importance of the lymphatics in the pathogenesis of paracoccidioidomycosis.