Complement Inhibition Keeps Mothers Calm and Avoids Fetal Rejection

The paternal antigens presented by the fetus could be considered foreign by the mother's immune system and elicit an immune response. Here we show that the complement system functions as an effector in fetal rejection in two different mouse models of pregnancy loss. In a mouse model of fetal loss and growth restriction (IUGR) induced by antiphospholipid antibodies (aPL), we found that complement activation is a crucial and early mediator of pregnancy loss. We demonstrated that C5a-C5aR interaction and neutrophils are key mediators of fetal injury. We identified tissue factor (TF) as a critical intermediate that, acting downstream of C5 activation, enhances neutrophil activity and trophoblast injury. In an antibody-independent mouse model of spontaneous miscarriage and IUGR (CBAxDBA) we also identified C5a as an essential mediator. Complement activation caused dysregulation of the angiogenic factors (deficiency of free vascular endothelial growth factor (VEGF) and elevated levels of soluble VEGF receptor 1) required for normal placental development. Inhibition of complement activation prevented angiogenesis failure and rescued pregnancies. Our studies in antibody-dependent and antibody-independent models of pregnancy complications identified complement activation as the crucial mediator of damage and will allow development of new interventions to prevent pregnancy loss and IUGR.     

Uptake of 153Sm-DTPA-bis-biotin and 99mTc-DTPA-bis-biotin in rat as-30D-hepatoma cells

Labeled biotin has been used mainly for pretargeted therapy, an approach for increasing the amount of radioactivity delivered to a cancer cell. The aim of this investigation was to prepare (153)Sm-DTPA-bis-biotin and (99m)Tc-DTPA-bis-biotin in order to study their in vitro and in vivo uptake in rat AS-30D hepatoma cells found in ascites and in implanted tumor. DTPA-bis-biotin (pH 8) was (153)Sm labeled with (153)SmCl(3) and (99m)Tc-DTPA-bis-biotin was prepared via SnCl(2) reduction. Radiochemical purity was >98% in both cases. AS-30D hepatoma cells were obtained from ascites of a rat with hepatoma and were propagated in the peritoneum cavity of normal rats. In vitro ascites cell (153)Sm-DTPA-bis-biotin uptake was compared with (153)SmCl(3) cell uptake. The ratio cell (153)Sm-DTPA-bis-biotin/(153) SmCl(3) was 39.6 and when avidin was added it increased to 50. The ratio (99m)Tc-DTPA-bis-biotin/TcO(4)Na was 8.7. Concentration of (153)Sm-DTPA-bis-biotin in tumor 2, 3 and 24 h after administration, was 5, 15 and 3 times higher than in normal muscle (T/nT). Biodistribution in a 0.083-24 h time period showed that (153)Sm-DTPA-bis-biotin was taken up only by ascites tumor cells and hepatoma cells. Two and 3 h ratio ascites/liver (As/Lv) was 6.4 and 6.0. For (99m)Tc-DTPA-bis-biotin 2 and 3 h T/nT was 15.7 and 4.7 and 2 h As/Lv was 1.4. In conclusion, both radiopharmaceuticals show high uptake in rat AS-30D hepatoma cells in ascites and in implanted tumor. Since lung, thyroid, kidney, liver or pancreas carcinomas are ascites producing cancers (153)Sm-DTPA-bis-biotin would be an adequate therapeutic radiopharmaceutical for these patients whose life quality would be enhanced with control of ascites, and a reduction of the primary tumor and its metastases.     

Effect of Arsenite on Nitrosative Stress in Human Breast Cancer Cells and Its Modulation by Flavonoids

Arsenic (As) is used in the treatment of leukemia and breast cancer due to its oxidative cytotoxic action. However, it is also toxic to normal cells. One proposed anticancer mechanism induced by As might be nitrosative stress (NS). It is believed that antioxidant flavonoids in combination with As might reduce its toxic action on normal cells without interfering with its antitumor action. In the present study, we evaluated the antineoplastic potential of As on breast human cancer lines MCF-7 and ZR-75-1 treated with redox-modulating flavonoids, such as quercetin (Q) and silymarin (S). Even though both cell lines differed about their oxidative responsiveness, their viability was decreased by NS induction through γ-glutamyltranspeptidase inhibition. Arsenic triggered NS in both MCF-7 and ZR-75-1 cultures, with the formers more sensitive without recovering their pre-treatment capacity. ZR-75-1 cells maintained their antioxidant status, whereas MCF-7 ones treated with S, As, and As + Q did not. Silymarin did not interfere with the described As bioactivity. NS was an anticancer mechanism exerted by As depending on the redox cellular response that could be differentially modified by dietary antioxidants. Hence, it is worthwhile to consider the use of dietary antioxidants as adjuvant in cancer chemotherapy, especially when using As.     

Suspension-Vero cell cultures as a platform for viral vaccine production

Since Vero cells are currently considered as an acceptable cell substrate to produce a wide range of viruses, we developed a virus production platform using Vero cells adapted to grow in suspension in serum-free media. After adapting anchorage-dependent Vero cells to grow as a free-cell suspension, vesicular stomatitis virus, herpes simplex virus 1 and polio virus 1 production rates were evaluated in batch cultures using spinner flasks and perfused cultures in a bioreactor. The achieved results constitute valuable information for the development of a low-cost high-productivity process using a suspension culture of Vero cells to produce viral vaccines.     

The changing epidemiology of hepatitis C virus (HCV) infection in haemodialysis: European multicentre study.

BACKGROUND: The high prevalence of anti-hepatitis C virus (HCV) antibodies in HD patients has been known since the early 1990s but its evolution over the last decade is poorly documented. METHODS: All chronic HD patients from 15 Belgian units were tested at (re)start of HD and every 18 months for anti-HCV antibodies (ELISA 2 in May 1991 and November 1992, then ELISA 3 until May 2000). All chronic HD patients from HD units from eight other European countries, whose prevalence of anti-HCV (+) patients had been studied in 1991-1994 (and published except in one country), were tested for anti-HCV antibodies in 1999. RESULTS: Anti-HCV (+) prevalence decreased (P<0.001) from 13.5 (1991) to 6.8% (2000) in the Belgian cohort (n = 1710). Prevalence also decreased (P<0.05) in the participating units from France (42-30%), Sweden (16-9%) and Italy (28-16%), tended to decrease in the participating units from UK (7-3%, P = 0.058) and Hungary (26-15%, P = 0.057) but did not change (NS) in the participating units from Germany (7 to 6%), Spain (5 to 12%) and Poland (42 to 44%). In the Belgian cohort, the prevalence of anti-HCV(+) at (re)start of HD did not change significantly over 1991-2000. CONCLUSION: The prevalence of anti-HCV(+) in HD has decreased markedly over the last decade in the participating units from most European countries. This decrease should reduce further the risk of nosocomial and occupational HCV infection in HD and ultimately contribute to improved long-term prognosis of HD patients and kidney graft recipients.     

Virus-specific effector CD4+ T-cell responses in hemodialysis patients with hepatitis C virus infection

Patients with chronic renal failure undergoing hemodialysis who are infected with hepatitis C virus (HCV) may test consistently anti-HCV negative. Because CD4(+) T-cells provide help for antibody production virus-specific effector CD4(+) T-cell responses were investigated in relation to anti-HCV positivity in 15 hemodialysis patients grouped according to HCV antibody and viremia. CD4(+) T-cell reactivity was studied in peripheral blood mononuclear cells by standard lymphocyte proliferation assay and phenotypic/functional characterization (cell-surface staining/cytokine secretion) by flow cytometry. HCV-specific CD4(+) T-cell proliferation in viremic hemodialysis patients was weak or absent independently of their anti-HCV status. Virus-specific CD4(+) T-cells displayed a memory phenotype and showed low to undetectable capacity to secrete effector interferon (IFN)-gamma. Impaired activation-induced cytokine secretion appeared to be Th1 (IFN-gamma) but not Th2 (interleukin-4)-directed and was virus-specific as cytomegalovirus responses were preserved. The frequency ex vivo of CD3(+)CD4(+)IFN-gamma(+) T-cells was independent of the HCV antibody status and comparable between viremic (range: 0.08-1.54%) or non-viremic (0.11-3.2%) hemodialysis patients and healthy donors (0.13-1.10%; P = 0.58). The numbers of CD3(+)CD4(+)IFN-gamma(+) T-cells augmented slightly (P = 0.047) in HCV-infected hemodialysis patients but markedly in only one (greater than ninefold) after HCV stimulation. In conclusion, hemodialysis patients show limited HCV-specific effector CD4(+) Th1-cell responses which nonetheless seem unrelated to the anti-HCV status and are not more impaired due to the ongoing hemodialysis.     

Molecular identification and susceptibility profile of Sporothrix schenckii sensu lato isolated in Argentina

We studied 23 clinical and environmental strains of Sporothrix schenckii sensu lato collected from 1984 to 2017 in Argentina. The molecular identification (partial sequencing of a fragment of the calmodulin gene) of the strains was performed. For the yeast and mycelial phases, the in vitro susceptibility testing by a microdilution reference method was determined against eight antifungal drugs. Strains studied were identified as S. schenckii sensu stricto 13 (56.5%), S. brasiliensis 8 (34.7%) and S. globosa 2 (8.7%). The most active antifungal drugs tested for the yeast and mycelial phases expressed as geometric mean (GM ) value of the minimal inhibitory concentration (MIC ) (μg mL^?1) were terbinafine (0.07 and 0.24), posaconazole (0.13 and 0.58), itraconazole (0.38 and 1.10) and ketoconazole (0.22 and 0.89), while fluconazole (110.10 and 131.92) and flucytosine (2.96 and 79.03) were the less active. For voriconazole and amphotericin B the GM ‐MIC values were acceptably low for the yeast phase (0.39 and 0.72 μg mL^?1), while the mycelial phase showed values ≥2‐fold higher (8.76 and 1.88 μg mL^?1), P  < .05. Here, we described S. schenckii sensu stricto, S. brasiliensis and S. globosa, these species were isolated from humans, animals and soil and are circulating in Argentina since at least 1984.     

Complement C3 activation is required for antiphospholipid antibody-induced fetal loss.

The antiphospholipid syndrome (APS) is characterized by recurrent fetal loss, vascular thrombosis, and thrombocytopenia occurring in the presence of antiphospholipid (aPL) antibodies. The pathogenesis of fetal loss and tissue injury in APS is incompletely understood, but is thought to involve platelet and endothelial cell activation as well as procoagulant effects of aPL antibodies acting directly on clotting pathway components. Recent studies have shown that uncontrolled complement activation in the placenta leads to fetal death in utero. We hypothesized that aPL antibodies activate complement in the placenta, generating split products that mediate placental injury and lead to fetal loss and growth retardation. To test this hypothesis, we used a murine model of APS in which pregnant mice are injected with human IgG containing aPL antibodies. We found that inhibition of the complement cascade in vivo, using the C3 convertase inhibitor complement receptor 1-related gene/protein y (Crry)-Ig, blocks fetal loss and growth retardation. Furthermore, mice deficient in complement C3 were resistant to fetal injury induced by aPL antibodies. While antigenic epitopes recognized by aPL antibodies are important in the pathogenesis of APS, our data show that in vivo complement activation is required for aPL antibody-induced fetal loss and growth retardation.