Resistance to oxamnique of a Schistosoma mansoni strain isolated from patient submitted to repeated treatments

Uma cepa de Schistosoma mansoni (R) foi isolada de paciente previamente submetido a quatro tratamentos com o oxamniquine e a um outro praziquantel. Os resultados obtidos com o teste quimioterapeutico, usando oxcamniquine em camundongos infectados com as cepas R1 e Le (padrao) mostraram resistencia evidente a droga em vermes de cepa R1. Assim, com a dose de 250 mg/kg de oxamniquine, todos os camundongos (17) dos 17 camundongos infectados com a cepa R1 apresentaram vermes sobreviventes...

Effect of gamma interferon and interleukin 10 on phosphoinositol turnover by human neutrophils in vitro

We evaluated the levels of inositolmono-(IP1), di-(IP2), tri- (IP3) and tetraphosphates (IP4) in human neutrophils (N) stimulated with gamma interferon (IFN-gamma) (200 mul from a pool of cell culture supernatant obtained from 1 x 10(7) PHA-primed peripheral blood mononuclear cells (30-60 min at 37 degrees Celsius, 5 per cent CO2) in the presence or in the absence of interleukin 10 (IL-10) (10 mug/10mul). The results, reported as mean + SEM cpm, showed that IFN-gamma induced a significant increase only in the IP3 level (N + medium = 1.413 + 172 and N + IFN-gamma = 8,875 + 832). However, this activation mediated by IFN-gamma was blocked partially in the presence of IL-10 (N + IFN-gamma + IL-10 = 2,430 + 239) (P<0.05). Interleukin 10 alone did not induce significant alterations in the content of IP1 (1,203 + 123), IP2 (1,880 + 163), IP3 (938 + 102) or IP4 (2,403 + 345) when compared to the respective controls in the absence of IL-10 (IP1 = 1,625 + 132; IP2 = 1,343 + 149; IP3 = 1,413 + 172 and IP4 = 3,281 + 234). We also demonstrated the inhibitory effect of IL-10 on chemoluminescence generation by human neutrophils during phagocytosis of opsonized particles (OZ). Chemoluminescence generation was enhanced by IFN-gamma (N + OZ = 42.8 + 3.9 and N + OZ + IFN-gamma = 66.5 + 4.3) and this effect was reduced by IL-10 (N + OZ + IFN-gamma + IL-10 = 37.6 + 5.1). These data suggest that IL-10 modulates the neutrophil response and may be important for the development of new treatments of inflammatory injury.

Human giant cell formation induced in vitro by Schistosoma mansoni antigens

Although multinucleated giant cells have been described for many years in association with different chronic inflammatory responses, their participation in immunoregulatory mechanisms within the schistosome egg granulomas remains to be clarified. In this study we determined if soluble egg antigen (SEA) or adult worm antigen preparations (SWAP) from S. mansoni induce giant cell formation in vitro and their relationship with the intensity of granulomatous reactivity. Antigenic stimulation of peripheral blood mononuclear cells (PBMC) from patients (N = 9) with active schistosomiasis infection increased giant cell formation per field after the 12th day in culture when treated with S. mansoni SEA conjugated to polyacrylamide beads (PB-SEA) (17 +/- 1.2) and SWAP (PB-SWAP) (18.5 +/- 1.5). The increase in the number of giant cells was statistically significant when compared to the control polyacrylamide beads (PB) (9 +/- 1.1) and purified protein derivative conjugated to beads (PB-PPD) (11.6 +/- 1.7). We also observed a correlation between an increase in the number of giant cells and a decrease in in vitro granuloma index (GI) to PB-SEA (GI decreased from 4.3 +/- 0.2 on the 6th day to 3.2 +/- 0.2 on the 12th day) and PB-SWAP (GI decreased from 4.8 +/- 0.3 on the 6th day to 3.5 +/- 0.05 on the 12th day). These data suggest that giant cell formation may be one of the immunoregulatory mechanisms involved in the down-regulation of the granuloma reaction against S. mansoni eggs