Macrophages co-incubated with Candida albicans strain CR1 in vitro showed early signs of apoptosis, but evolved to necrosis after 2 h. In this study, we investigated whether strain CR1 caused apoptosis or necrosis of macrophages after its inoculation into mice peritoneal cavity, and whether this correlated with the secretion of IL-10. Peritoneal macrophages from mice that received an inoculum of C. albicans CR1 showed signs of apoptosis and necrosis from 30 min to 2 h afterwards, whereas heat-killed C. albicans did not cause those effects. IL-10 production was low during the first 6 h post-infection, when macrophages predominated in the peritoneal exudate, whereas its higher production after 24 h correlated with an increase of neutrophils in the exudate. Treatment of CR1 with pepstatin (an inhibitor of proteinases) prevented the process of apoptosis and significantly reduced IL-10 production, suggesting that the increased production of IL-10 was caused by processes occurring during the initial phase of infection, such as apoptosis, necrosis and uptake of death cells.
The immunoregulatory effect of Artin M and jacalin from extract of Artocarpus integrifolia seeds (jack extract) against infection with Candida albicans was investigated. Swiss mice received jack extract containing 500 μg protein/ml PBS intraperitoneally (i.p.) or PBS alone and after 72 h were infected i.p. with C. albicans CR15 (10(7)) and sacrificed after 30 min, 2, 6, 24, and 72 h. ELISA analysis revealed that in jack extract-treated mice IFN-γ was predominantly produced versus IL-10 in control mice. These results suggest that jack extract induced a protective immune response, since C. albicans clearance was complete at 72 h postinfection. Jack extract presents two lectins (Artin M and jacalin) with distinct biological properties. Artin M was able to induce IL-12 production by macrophages. Also, Artin M in different concentrations, associated with jacalin or in jack extract induced both IFN-γ and IL-17 production. As a consequence, phagocytic and candidacidal activity increased significantly. Alanine aminotransferase activity (ALT) was used as parameter for damage of the liver. The activity of ALT correlated with inoculum size that increased significantly in control group, however, mice pretreated with jack extract 3 days before infection presented normal ALT. Mice pretreated with jack extract that received a lethal inoculum of Candida presented 90% survival versus 20% among controls or mice pretreated with jacalin. Thus, the results suggest that Artin M by itself, associated with jacalin or present in jack extract is able to induce protective Th1 and Th17 immune responses against Candida albicans infection.
The antileishmanial and immunomodulatory effects of propolis collected in Botucatu, São Paulo State, Brazil, were evaluated in Leishmania (Viannia) braziliensis experimental infection. The antileishmanial effect of propolis on promastigote forms was verified by reducing growth and by promoting morphologic alterations observed by scanning electron microscopy. In in vitro immunomodulatory assays, macrophages were pretreated with propolis and then infected with L. (V.) braziliensis. In vivo, supernatants from liver cells and peritoneal exudate of BALB/c mice pretreated with propolis and infected with Leishmania (107/mL promastigotes) were collected, and TNF-α and IL-12 were measured by ELISA. Macrophages incubated with propolis showed a significant increase in interiorization and further killing of parasites. An increased TNF-α production was seen in mice pretreated with propolis, whereas IL-12 was downregulated during the infection. In conclusion, Brazilian propolis showed a direct action on the parasite and displayed immunomodulatory effects on murine macrophages, even though the parasite has been reported to affect the activation pathways of the cell. The observed effects could be associated with the presence of phenolic compounds (flavonoids, aromatic acids, and benzopyranes), di- and triterpenes, and essential oils found in our propolis sample.
SummaryTo evaluate the long-term effect of mild-early maternal protein malnutrition on weight gain, hematological parameters and macrophage function in rats at adult age, we compared rats whose dams were fed diets containing either 9.5% (low protein-LPD) or 23% protein (normal-NPD) for the first 12 d of lactation. At 80 d of age, the functions of spreading, phagocytosis and killing Candida albicans were determined in resident peritoneal macrophages, whereas leukocytes and red blood cells were counted in peripheral blood. The number of resident peritoneal macrophages from LPD was the same as from NPD, but the ability of spreading and phagocytosing opsonised yeast was impaired. Besides, they were not able to block the germ tube formation or kill C. albicans to the same extent as in the control group. The low protein diet produced a significant reduction in the pups' growth and in hematological parameters although no difference was found in leukocyte counts. Taken together the data suggest that protein malnutrition during early lactation induces permanent alterations in macrophage function, body composition and hematological status, which are not restored completely even after a normal protein diet is supplied.
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