Association of IgG immunoglobulin and subclasses level with the severity of chromoblastomycosis due to Fonsecaea pedrosoi and therapeutic response to itraconazole.

Chromoblastomycosis (CBM) is a chronic, suppurative, granulomatous mycosis of the skin and subcutaneous tissues. The aim of this study was to evaluate the association between IgG antibody levels and the severity of CBM and therapeutic response of patients to itraconazole. A longitudinal study was conducted in patients with CBM due to Fonsecaea pedrosoi and in healthy subjects with chromomycin skin test (CST)+. The dosage of anti-F. pedrosoi IgG antibody performed in 47 healthy individuals with CST+ showed positivity in 97.5 %, with an average titer of 2,109 [standard deviation (SD) + 3,676)] and a mean optical density (OD) of 1.174 (SD + 0.456), showing positive correlation with the induration area of the CST (mm(2)). The level of antibodies in 55 patients with CBM expressed in OD and titration showed that, before treatment, patients with severe disease had higher levels of IgG, IgG1, IgG2, and IgG3 when compared with moderate or mild disease (p < 0.05). According to the time of treatment, the mean antibody titers of IgG, IgG1, and IgG2 were reduced after treatment (p < 0.05). In the assessment of therapeutic response, there was reduction of IgG3 and IgG titers in patients with rapid response (p < 0.05) and IgG2 on rapid and intermediate response (p < 0.05). There was clear evidence of what are the risk factors for exposure to F. pedrosoi in the daily lives of these subjects, with prospects of preventive measures for the target population. The immunological analysis shows that the antibody anti-F. pedrosoi did not exhibit a protective role against infection caused by this agent.

Saliva as a source of HCMV DNA in allogeneic stem cell transplantation patients.

OBJECTIVE: The purpose of this study was to investigate the use of saliva for the identification of human cytomegalovirus (HCMV) in allogeneic hematopoietic stem cell transplant patients by real time PCR compared with blood. MATERIALS AND METHODS: Saliva and blood samples were sampled weekly in 30 allogeneic hematopoietic stem cell transplant patients until 100 days after transplant. Total genomic DNA, extracted from saliva and whole-blood samples, was used for HCMV real time PCR. Nonparametric tests were performed, and P value

Detection of malaria liver-stages in mice infected through the bite of a single Anopheles mosquito using a highly sensitive real-time PCR.

We describe a highly sensitive real-time PCR to detect and measure the development of the liver-stages of malaria parasites in mice infected with sporozoites ranging in number from 25 to more than 164,000, using the same reaction conditions. Furthermore, this assay detects and measures parasite loads in the livers of mice exposed to the bite of a single malaria-infected Anopheles mosquito. This unique method should greatly facilitate studies aimed at evaluating very precisely the efficacy of anti-malarial experimental drug treatments and vaccination regimens in conditions of infection resembling those found in the field.

Complete, long-lasting protection against malaria of mice primed and boosted with two distinct viral vectors expressing the same plasmodial antigen.

We report that complete protection against malaria and total inhibition of liver stage development and parasitemia was obtained in 100% of BALB/c mice primed with a replication-defective recombinant adenovirus expressing the circumsporozoite (CS) protein of Plasmodium yoelii (AdPyCS), followed by a booster with an attenuated recombinant vaccinia virus, expressing the same malaria antigen, VacPyCS. We found increased levels of activated CS-specific CD8(+) and CD4(+) T cells, higher anti-sporozoite antibody titers, and greater protection in these mice, when the time between priming and boosting with these two viral vectors was extended from 2 to 8 or more weeks. Most importantly, by using this immunization regimen, the protection of the immunized mice was found to be long-lasting, namely complete resistance to infection of all animals 3 1/2 months after priming. These results indicate that immunization with AdPyCS generates highly effective memory T and B cells that can be recalled long after priming by boosting with VacPyCS.

Dendritic cells can initiate protective immune responses against malaria.

An understanding of the antigen presentation mechanisms that mediate induction of protective immune responses against malaria is essential for the development of successful immunization approaches. Here we show that dendritic cells presenting Plasmodium yoelii sporozoite antigens are able to activate specific CD4(+) and CD8(+) T cells and initiate protective immune responses against malaria in mice.

alpha -galactosylceramide-activated Valpha 14 natural killer T cells mediate protection against murine malaria.

Natural killer T (NKT) cells are a unique population of lymphocytes that coexpress a semiinvariant T cell and natural killer cell receptors, which are particularly abundant in the liver. To investigate the possible effect of these cells on the development of the liver stages of malaria parasites, a glycolipid, alpha-galactosylceramide (alpha-GalCer), known to selectively activate Valpha14 NKT cells in the context of CD1d molecules, was administered to sporozoite-inoculated mice. The administration of alpha-GalCer resulted in rapid, strong antimalaria activity, inhibiting the development of the intrahepatocytic stages of the rodent malaria parasites Plasmodium yoelii and Plasmodium berghei. The antimalaria activity mediated by alpha-GalCer is stage-specific, since the course of blood-stage-induced infection was not inhibited by administration of this glycolipid. Furthermore, it was determined that IFN-gamma is essential for the antimalaria activity mediated by the glycolipid. Taken together, our results provide the clear evidence that NKT cells can mediate protection against an intracellular microbial infection.

Induction of cytotoxic T-cell response against hepatitis C virus structural antigens using a defective recombinant adenovirus.

A replication-defective recombinant adenovirus (RAd), RAdCMV-CE1, containing core and E1 genes of hepatitis C virus (HCV) was constructed. RAdCMV-CE1 was able to express core and E1 proteins both in mice and human cells. Immunization of BALB/c mice with RAdCMV-CE1 induced a specific cytotoxic T-cell response against the two HCV proteins. This response was characterized using a panel of 60 synthetic 14- or 15-mer overlapping peptides (10 amino-acid overlap) spanning the entire sequence of these proteins. Five main epitopes were found in the core protein, four of which had been previously described either in mice or humans. One single novel epitope was found in E1. Fine mapping of this E1 determinant, showed that octamer GHRMAWDM is the minimal epitope recognized by cytotoxic T lymphocytes (CTL). The cytotoxic T-cell response was H-2d restricted, lasted for at least 100 days, and was mediated by T cells with the classic CD4-CD8+ phenotype. This work demonstrates that replication-defective recombinant adenoviruses can efficiently express HCV proteins and are able to induce an in vivo cytotoxic T-cell response against a diversity of epitopes from HCV antigens. These vectors should be taken into consideration in the design of vaccines and also as a means to stimulate specific T-cell responses in chronic HCV carriers.