Prevalence and genotyping of hepatitis C virus in blood donors in the state of Pará, Northern Brazil

Given the scarcity of epidemiological information on hepatitis C virus (HCV) infection in Northern Brazil, we determined the prevalence and genotypic frequency in blood donors in the state of Pará (PA). Blood samples from all of the blood donors at the Fundação HEMOPA (blood bank of PA) from 2004-2006 were screened for the presence of antibodies to anti-HCV and samples seroreactive to anti-HCV were further tested for HCV RNA using real-time PCR. In total, 116 HCV-RNA samples were genotyped, based on maximum likelihood phylogenetic analyses, using BioEdit, Modelgenerator, PHYML and FigTree software. The population consisted of 242,726 volunteers who donated blood from 2004-2006; the most common subgroup was males between the ages of 18-29 years old (37.30%). Within the whole group, 1,112 blood donors (0.46%) had indeterminate or positive serology; among these, 28.78% were males whose ages ranged from 18-29 years. A diagnosis of chronic HCV infection was confirmed for 304 donors (60.20% males; 66.45% were 30-49 years old), resulting in a prevalence of HCV RNA in 0.13% of the samples (304 of 242,726). HCV genotyping revealed a high frequency of genotype 1 (108/116) followed by genotype 3 (8/116). This study found HCV infection to be relatively infrequent in PA; genotype 1 was most commonly isolated. This information can help guide prevention and control policies aimed at efficient diagnosis and control measures.

Vaccinia virus regulates expression of p21WAF1/Cip1 in A431 cells

In this paper, we provide evidence that both the mRNA and protein levels of the cyclin-dependent kinase (CDK) inhibitor p21WAF1/CDK-interacting protein 1 (Cip1) increase upon infection of A431 cells with Vaccinia virus (VACV). In addition, the VACV growth factor (VGF) seems to be required for the gene expression because infection carried out with the mutant virus VACV-VGF- revealed that this strain was unable to stimulate its transcription. Our findings are also consistent with the notion that the VGF-mediated change in p21WAF1/Cip1 expression is dependent on tyrosine kinase pathway(s) and is partially dependent on mitogen-activated protein kinase/extracellular-signal regulated kinase 1/2. We believe that these pathways are biologically significant because VACV replication and dissemination was drastically affected when the infection was carried out in the presence of the relevant pharmacological inhibitors.

Laboratorial atopy markers in children with human immunodeficiency virus

Changes in immune system functions are one of the most important consequences of human immunodeficiency virus (HIV) infection. Studies have reported a higher prevalence of disease mediated by immunological hypersensitivity mechanisms in HIV-positive patients. This study aims to observe how immunological changes in HIV-infected children interfere in atopy determinants. Fifty-seven HIV-positive children were studied between June 2004-August 2005 to evaluate the possible modifications in atopy diagnosis from prick test environmental allergen reactivity. Patients were subjected to two evaluations: on both occasions, atopic and non-atopic groups were correlated with immunological (CD4+ and CD8+ lymphocyte concentrations and serum levels of IgA, IgM, IgG and IgE) and viral parameters (HIV viral load). The percent atopy was 20.05 in the first and 29.82 in the second evaluation and atopy was diagnosed in patients without immunosuppression or with moderate immunosuppression. Six patients changed from a negative to a positive atopy profile. One patient with a decreased CD4+ T lymphocyte concentration failed to demonstrate prick test positivity between evaluations. Multivariate analysis showed that the variables associated with atopy diagnosis included a personal history of allergic diseases as well as elevated IgE for age and elevated IgE levels. Atopy development in HIV-infected children seems to be modulated by genetic and environmental factors as well as immunological condition.

Prevalence and genotypes of hepatitis C virus among injecting drug users from Salvador-BA, Brazil

Hepatitis C virus (HCV) is the major infectious disease agent among injecting drug users (IDUs), with seroprevalence ranging from 50-90%. In this paper, serological and virological parameters were investigated among 194 IDUs, 94 ex-IDUs and 95 non-IDUs that were sampled by the "snowball" technique in three localities renowned for both intense drug use and trafficking activities in Salvador, Brazil. The majority of the participants were male, but sex and mean age differed significantly between IDUs/ex-IDUs and non-IDUs (p < 0.05). Anti-HCV screening revealed that 35.6%, 29.8% and 5.3% of samples from IDUs, ex-IDUs and non-IDUs, respectively, were seropositive. HCV-RNA detection confirmed that the prevalence of infection was 29.4%, 21.3% and 5.3% for IDUs, ex-IDUs and non-IDUs, respectively. Genotyping analysis among IDUs/ex-IDUs determined that 76.9% were infected with genotype 1, 18.5% with genotype 3 and 4.6% with a mixed genotype; this result differed significantly from non-IDUs, where genotype 3 was the most frequent (60%), followed by genotype 1 (20%) and a mixed genotype (20%). We report a significantly higher prevalence of HCV infection in IDUs/ex-IDUs compared to the control group (p < 0.001). Although the sample size of our study was small, the differences in HCV genotype distribution reported herein for IDUs/ex-IDUs and non-IDUs warrant further investigation.

Virucidal activity of Colombian Lippia essential oils on dengue virus replication in vitro

The inhibitory effect of Lippia alba and Lippia citriodora essential oils on dengue virus serotypes replication in vitro was investigated. The cytotoxicity (CC50) was evaluated by the MTT assay and the mode of viral inhibitory effect was investigated with a plaque reduction assay. The virus was treated with the essential oil for 2 h at 37ºC before cell adsorption and experiments were conducted to evaluate inhibition of untreated-virus replication in the presence of oil. Antiviral activity was defined as the concentration of essential oil that caused 50% reduction of the virus plaque number (IC50). L. alba oil resulted in less cytotoxicity than L. citriodora oil (CC50: 139.5 vs. 57.6 μg/mL). Virus plaque reduction for all four dengue serotypes was observed by treatment of the virus before adsorption on cell. The IC50 values for L. alba oil were between 0.4-32.6 μg/mL and between 1.9-33.7 μg/mL for L. citriodora oil. No viral inhibitory effect was observed by addition of the essential oil after virus adsorption. The inhibitory effect of the essential oil seems to cause direct virus inactivation before adsorption on host cell.

Manufacturing and characterization of a recombinant adeno-associated virus type 8 reference standard material.

Gene therapy approaches using recombinant adeno-associated virus serotype 2 (rAAV2) and serotype 8 (rAAV8) have achieved significant clinical benefits. The generation of rAAV Reference Standard Materials (RSM) is key to providing points of reference for particle titer, vector genome titer, and infectious titer for gene transfer vectors. Following the example of the rAAV2RSM, here we have generated and characterized a novel RSM based on rAAV serotype 8. The rAAV8RSM was produced using transient transfection, and the purification was based on density gradient ultracentrifugation. The rAAV8RSM was distributed for characterization along with standard assay protocols to 16 laboratories worldwide. Mean titers and 95% confidence intervals were determined for capsid particles (mean, 5.50×10(11) pt/ml; CI, 4.26×10(11) to 6.75×10(11) pt/ml), vector genomes (mean, 5.75×10(11) vg/ml; CI, 3.05×10(11) to 1.09×10(12) vg/ml), and infectious units (mean, 1.26×10(9) IU/ml; CI, 6.46×10(8) to 2.51×10(9) IU/ml). Notably, there was a significant degree of variation between institutions for each assay despite the relatively tight correlation of assay results within an institution. This outcome emphasizes the need to use RSMs to calibrate the titers of rAAV vectors in preclinical and clinical studies at a time when the field is maturing rapidly. The rAAV8RSM has been deposited at the American Type Culture Collection (VR-1816) and is available to the scientific community.

Quantitation of endogenous mouse mammary tumor virus superantigen expression by lymphocyte subsets.

Superantigens (SAg) encoded by endogenous mouse mammary tumor viruses (Mtv) interact with the V beta domain of the T cell receptor (TcR-V beta). Presentation of Mtv SAg can lead to stimulation and/or deletion of the reactive T cells, but little is known about the quantitative aspects of SAg presentation. Although monoclonal antibodies have been raised against Mtv SAg, they have not been useful in quantitating SAg protein, which is present in very low amounts in normal cells. Alternative attempts to quantitate Mtv SAg mRNA expression are complicated by the fact that Mtv transcription occurs from multiple loci and in different overlapping reading frames. In this report we describe a novel competitive polymerase chain reaction assay which allows the locus-specific quantitation of SAg expression at the mRNA level in lymphocyte subsets from mouse strains with multiple endogenous Mtv loci. In B cells as well as T cells (CD4+ or CD8+), Mtv-6 SAg is expressed at the highest levels, followed by Mtv-7 SAg and (to a much lesser extent) Mtv-8,9. Consistent with functional Mtv-7 SAg presentation studies, we find that Mtv-7 SAg expression is higher in B cells than in CD8+ T cells and very low in the CD4+ subset. The overall hierarchy in Mtv SAg expression (i.e. Mtv-6 &gt; Mtv-7 &gt; Mtv 8,9) was also observed for mRNA isolated from neonatal thymus. Furthermore, the kinetics of intrathymic deletion of the corresponding TcR-V beta domains during ontogeny correlated with the levels of Mtv SAg expression. Collectively our data suggest that T cell responses to Mtv SAg are largely controlled by SAg expression levels on presenting cells.

Improved efficiency of a Salmonella-based vaccine against human papillomavirus type 16 virus-like particles achieved by using a codon-optimized version of L1.

Cervical cancer results from cervical infection by human papillomaviruses (HPVs), especially HPV16. An effective vaccine against these HPVs is expected to have a dramatic impact on the incidence of this cancer and its precursor lesions. The leading candidate, a subunit prophylactic HPV virus-like particle (VLP) vaccine, can protect women from HPV infection. An alternative improved vaccine that avoids parenteral injection, that is efficient with a single dose, and that induces mucosal immunity might greatly facilitate vaccine implementation in different settings. In this study, we have constructed a new generation of recombinant Salmonella organisms that assemble HPV16 VLPs and induce high titers of neutralizing antibodies in mice after a single nasal or oral immunization with live bacteria. This was achieved through the expression of a HPV16 L1 capsid gene whose codon usage was optimized to fit with the most frequently used codons in Salmonella. Interestingly, the high immunogenicity of the new recombinant bacteria did not correlate with an increased expression of L1 VLPs but with a greater stability of the L1-expressing plasmid in vitro and in vivo in absence of antibiotic selection. Anti-HPV16 humoral and neutralizing responses were also observed with different Salmonella enterica serovar Typhimurium strains whose attenuating deletions have already been shown to be safe after oral vaccination of humans. Thus, our findings are a promising improvement toward a vaccine strain that could be tested in human volunteers.

Trachea, lung, and tracheobronchial lymph nodes are the major sites where antigen-presenting cells are detected after nasal vaccination of mice with human papillomavirus type 16 virus-like particles.

Vaccination by the nasal route has been successfully used for the induction of immune responses. Either the nasal-associated lymphoid tissue (NALT), the bronchus-associated lymphoid tissue, or lung dendritic cells have been mainly involved. Following nasal vaccination of mice with human papillomavirus type 16 (HPV16) virus-like-particles (VLPs), we have previously shown that interaction of the antigen with the lower respiratory tract was necessary to induce high titers of neutralizing antibodies in genital secretions. However, following a parenteral priming, nasal vaccination with HPV16 VLPs did not require interaction with the lung to induce a mucosal immune response. To evaluate the contribution of the upper and lower respiratory tissues and associated lymph nodes (LN) in the induction of humoral responses against HPV16 VLPs after nasal vaccination, we localized the immune inductive sites and identified the antigen-presenting cells involved using a specific CD4(+) T-cell hybridoma. Our results show that the trachea, the lung, and the tracheobronchial LN were the major sites responsible for the induction of the immune response against HPV16 VLP, while the NALT only played a minor role. Altogether, our data suggest that vaccination strategies aiming to induce efficient immune responses against HPV16 VLP in the female genital tract should target the lower respiratory tract.

Hepatitis B genotype G and high frequency of lamivudine-resistance mutations among human immunodeficiencyvirus/hepatitis B virus co-infected patients in Brazil

In this study, we evaluated the hepatitis B virus (HBV) genotype distribution and HBV genomic mutations among a group of human immunodeficiency virus-HBV co-infected patients from an AIDS outpatient clinic in São Paulo. HBV serological markers were detected by commercially available enzyme immunoassay kits. HBV DNA was detected using in-house nested polymerase chain reaction and quantified by Cobas Amplicor. HBV genotypes and mutations in the basal core promoter (BCP)/pre-core/core regions and surface/polymerase genes were determined by sequencing. Among the 59 patients included in this study, 55 reported prior use of lamivudine (LAM) or tenofovir. HBV DNA was detected in 16/22 patients, with a genotype distribution of A (n = 12,75%), G (n = 2,13%), D (n = 1,6%) and F (n = 1,6%). The sequence data of the two patients infected with genotype G strongly suggested co-infection with genotype A. In 10 patients with viremia, LAM-resistance mutations in the polymerase gene (rtL180M + rtM204V and rtV173L + rtL180M + rtM204V) were found, accompanied by changes in the envelope gene (sI195M, sW196L and sI195M/sE164D). Mutations in the BCP and pre-core regions were identified in four patients. In conclusion, genotype G, which is rarely seen in Brazil, was observed in the group of patients included in our study. A high prevalence of mutations associated with LAM-resistance and mutations associated with anti-HBs resistance were also found among these patients.

Serologic evidence of the recent circulation of Saint Louis encephalitis virus and high prevalence of equine encephalitis viruses in horses in the Nhecolândia sub-region in South Pantanal, Central-West Brazil

As in humans, sub-clinical infection by arboviruses in domestic animals is common; however, its detection only occurs during epizootics and the silent circulation of some arboviruses may remain undetected. The objective of the present paper was to assess the current circulation of arboviruses in the Nhecolândia sub-region of South Pantanal, Brazil. Sera from a total of 135 horses, of which 75 were immunized with bivalent vaccine composed of inactive Eastern equine encephalitis virus (EEEV) and Western equine encephalitis virus(WEEV) and 60 were unvaccinated, were submitted to thorough viral isolation, reverse transcriptase polymerase chain reaction (RT-PCR) and neutralization tests for Saint Louis encephalitis virus (SLEV), EEEV, WEEV and Mayaro virus (MAYV). No virus was isolated and viral nucleic-acid detection by RT-PCR was also negative. Nevertheless, the prevalence of neutralizing antibodies in horses older than seven months was 43.7% for SLEV in equines regardless of vaccine status, and 36.4% for WEEV and 47.7% for EEEV in unvaccinated horses. There was no evidence of MAYV infections. The serologic evidence of circulation of arboviruses responsible for equine and human encephalitis, without recent official reports of clinical infections in the area, suggests that the Nhecolândia sub-region in South Pantanal is an important area for detection of silent activity of arboviruses in Brazil.

Epidemiology and molecular characterization of hepatitis B virus in Luanda, Angola

An estimated 360 million people are infected with hepatitis B virus (HBV) worldwide. Among these, 65 million live in Africa. Despite the high levels of hepatitis B in Africa, HBV epidemiology is still poorly documented in most African countries. In this work, the epidemiological and molecular characteristics of HBV infection were evaluated among the staff, visitors and adult patients (n = 508) of a public hospital in Luanda, Angola. The overall prevalence of hepatitis B core antibody (anti-HBc) and hepatitis B surface antigen was 79.7% and 15.1%, respectively. HBV infection was higher in males and was more prevalent in individuals younger than 50 years old. HBV-DNA was detected in 100% of HBV "e" antigen-positive serum samples and in 49% of anti-hepatitis Be antibody-positive samples. Thirty-five out of the 40 HBV genotypes belonged to genotype E. Circulation of genotypes A (4 samples) and D (1 sample) was also observed. The present study demonstrates that HBV infection is endemic in Luanda, which has a predominance of genotype E. This genotype is only sporadically found outside of Africa and is thought to have emerged in Africa at a time when the trans-Atlantic slave trade had stopped.

Genetic diversity of Toscana virus

Distribution of Toscana virus (TOSV) is evolving with climate change, and pathogenicity may be higher in nonexposed populations outside areas of current prevalence (Mediterranean Basin). To characterize genetic diversity of TOSV, we determined the coding sequences of isolates from Spain and France. TOSV is more diverse than other well-studied phleboviruses (e.g.,Rift Valley fever virus).

Soluble inflammatory markers as predictors of virological response in patients with chronic hepatitis C virus infection treated with interferon-α plus ribavirin

The host immune response plays an important role in viral clearance in patients who are chronically infected with hepatitis C virus (HCV) and are treated with interferon and ribavirin. Activation of the immune system involves the release of pro and anti-inflammatory molecules that can be measured in plasma samples. The present study aimed to evaluate the association between pretreatment plasma levels of chemokines and soluble tumor necrosis factor receptors (sTNF-R) and the virological response in treated patients with chronic hepatitis C infection. Forty-one chronically-infected HCV patients that were being treated with interferon-α (IFN-α) plus ribavirin were included in the study. Socio-demographic, clinical and laboratory data were collected and pretreatment plasma levels of chemokine CCL2, CCL3, CCL11, CCL24, chemokine CXCL9, CXCL10, sTNF-R1 and sTNF-R2 were measured. The virological response was assessed at treatment week 12, at the end of treatment and 24 weeks after treatment. Pretreatment CXCL10 levels were significantly higher in patients without an early virological response (EVR) or sustained virological response (SVR) compared to responders [512.9 pg/mL vs. 179.1 pg/mL (p = 0.011) and 289.9 pg/mL vs. 142.7 pg/mL (p = 0.045), respectively]. The accuracy of CXCL10 as a predictor of the absence of EVR and SVR was 0.79 [confidence interval (CI) 95%: 0.59-0.99] and 0.69 (CI 95%: 0.51-0.87), respectively. Pretreatment plasma levels of the other soluble inflammatory markers evaluated were not associated with a treatment response. Pretreatment CXCL10 levels were predictive of both EVR and SVR to IFN-α and ribavirin and may be useful in the evaluation of candidates for therapy.