Phylogenetic analysis of Dengue virus 1 isolated from South Minas Gerais, Brazil

Abstract Dengue is a major worldwide public health problem, especially in the tropical and subtropical regions of the world. Primary infection with a single Dengue virus serotype causes a mild, self-limiting febrile illness called dengue fever. However, a subset of patients who experience secondary infection with a different serotype can progress to a more severe form of the disease, called dengue hemorrhagic fever. The four Dengue virus serotypes (1–4) are antigenically and genetically distinct and each serotype is composed of multiple genotypes. In this study we isolated one Dengue virus 1 serotype, named BR/Alfenas/2012, from a patient with dengue hemorrhagic fever in Alfenas, South Minas Gerais, Brazil and molecular identification was performed based on the analysis of NS5 gene. Swiss mice were infected with this isolate to verify its potential to induce histopathological alterations characteristic of dengue. Liver histopathological analysis of infected animals showed the presence of inflammatory infiltrates, hepatic steatosis, as well as edema, hemorrhage and necrosis focal points. Phylogenetic and evolutionary analyses based on the envelope gene provided evidence that the isolate BR/Alfenas/2012 belongs to genotype V, lineage I and it is probably derived from isolates of Rio de Janeiro, Brazil. The isolate BR/Alfenas/2012 showed two unique amino acids substitutions (SER222THRE and PHE306SER) when compared to other Brazilian isolates from the same genotype/lineage. Molecular models were generated for the envelope protein indicating that the amino acid alteration PHE 306 SER could contribute to a different folding in this region located within the domain III. Further genetic and animal model studies using BR/Alfenas/2012 and other isolates belonging to the same lineage/genotype could help determine the relation of these genetic alterations and dengue hemorrhagic fever in a susceptible population.

Mapping the molecular characteristics of Brazilian human T-cell lymphotropic virus type 1 Env (gp46) and Pol amino acid sequences for vaccine design

This study was carried out to evaluate the molecular pattern of all available Brazilian human T-cell lymphotropic virus type 1 Env (n = 15) and Pol (n = 43) nucleotide sequences via epitope prediction, physico-chemical analysis, and protein potential sites identification, giving support to the Brazilian AIDS vaccine program. In 12 previously described peptides of the Env sequences we found 12 epitopes, while in 4 peptides of the Pol sequences we found 4 epitopes. The total variation on the amino acid composition was 9 and 17 percent for human leukocyte antigen (HLA) class I and class II Env epitopes, respectively. After analyzing the Pol sequences, results revealed a total amino acid variation of 0.75 percent for HLA-I and HLA-II epitopes. In 5 of the 12 Env epitopes the physico-chemical analysis demonstrated that the mutations magnified the antigenicity profile. The potential protein domain analysis of Env sequences showed the loss of a CK-2 phosphorylation site caused by D197N mutation in one epitope, and a N-glycosylation site caused by S246Y and V247I mutations in another epitope. Besides, the analysis of selection pressure have found 8 positive selected sites (w = 9.59) using the codon-based substitution models and maximum-likelihood methods. These studies underscore the importance of this Env region for the virus fitness, for the host immune response and, therefore, for the development of vaccine candidates.

Clonagem e expressão da glicoproteína transmembrana do vírus linfotrópico de células T humanas em sistema procarioto / Cloning and expression of the transmembranic glycoprotein from human T cell lymphotropic virus in a prokaryotic system

O HTLV-1 é o vírus causador da leucemia/linfoma de célula T no adulto e de uma desordem neurológica conhecida por mielopatia associada ao HTLV ou paraparesia espástica tropical. Um dos modos de transmissão é pelo sangue contaminado e seus subprodutos e, devido ao risco de infecções associadas ao HTLV sua pesquisa na triagem de doadores de sangue foi introduzida no Brasil a partir de 1993. Os kits diagnósticos utilizados nos bancos de sangue nacionais são na sua maioria comprados de empresas estrangeiras. O Brasil não detém a tecnologia para produção deste material e há a necessidade de produção de sistemas de diagnóstico com tecnologia nacional. Neste trabalho, mostramos a expressão da gp21/HTLV-1 em Escherichia coli e sua reatividade frente a anticorpos monoclonais e de pacientes infectados. Expressar tais proteínas é o primeiro passo para obtenção de conjuntos diagnósticos com tecnologia brasileira.

HTLV-1 is the virus that causes T cell lymphoma/leukemia in adults and a neurological disorder known as HTLV-associated myelopathy or tropical spastic paraparesis. One of the transmission means is through contaminated blood and its byproducts. Because of the risk of HTLV-associated infections, screening for HTLV was introduced for Brazilian blood donors in 1993. Most of the diagnostic kits used in the national blood banks are bought from foreign companies. Brazil does not have the technology to produce this material and there is a need to produce diagnostic systems with national technology. In this study, we show the expression of gp21/HTLV-1 in Escherichia coli and its reactivity towards monoclonal antibodies and the antibodies of infected patients. Expressing these proteins is the first step towards obtaining diagnostic kits with Brazilian biotechnology.

Identification and characterization of previously described epitopes in HIV-1 subtypes B, C, F and BF in Brazil

Genetic analysis of HIV-1 is essential to improve treatment strategies and select epitopes for vaccine programs. The objective of this study was to determine whether known CD4+ and CD8+ epitopes were present in Brazilian HIV-1 strains. We used previously described CD8+ and CD4+ epitopes from the Los Alamos laboratory to search for these epitopes in the Brazilian sequences using the HIVbase program and we compared the frequency results with the analyses using physical-chemical profile tools from Network Protein Sequence Analysis (NPSA), and the SYFPEITHI program. Furthermore, this analysis was carried out with the Prosite tool using the GeneDoc program and ds/dn analyses using the Synonymous Nonsynonymous Analysis Program (SNAP). The HIVbase epitope mapping demonstrated that 30 CD8+ and 6 CD4+ epitopes were present in the Brazilian sequences at a high frequency. Only two of these epitopes were heavily glycosylated. Interestingly, ds/dn analyses showed evidence of purifying selective pressure. These types of analyses could be useful for the assessment of possible vaccine efficiency in populations.

Adult T cell leukemia/lymphoma with lymphopenia in a Korean

We experienced a case of adult T cell leukemia/lymphoma (ATLL) in a 48-year-old Korean female, who has never been abroad since birth and no history of blood transfusion. The patient had hypercalcemia and multiple lymphadenopathy. Histopathologic study of left cervical lymph node (LN) and bone marrow (BM) revealed that infiltrates of malignant lymphoid cells were composed of small, medium and large cells with pleomorphic nuclei. Smears of peripheral blood (PB) showed lymphopenia (16%) with the appearance of a few atypical lymphoid cells (less than 2%), but not the typical clover leaf cells seen in ATLL. Immunophenotypic study of LN and BM revealed T cell phenotype. PB showed increased CD4+ T cell (T(H), CD3/CD4+, 57%) and decreased CD8+ T cell counts (T(S), CD3/CD8+, 6.7%). The sera of the patient and her family were reactive for HTLV-I antibody. The specific sequences of pol, env, and tax of HTLV-I DNA were detected in the lymphoma cells and peripheral blood mononuclear cells (PBMC) using polymerase chain reaction. Ultrastructural examination of PBMC confirmed numerous type c virus particles in extracellular space. This case was an acute type of ATLL without overt leukemic features in PB. Despite chemotherapy and intensive conservative treatment, she died 3 months after admission.