High genetic diversity of noroviruses in children from a community-based study in Rio de Janeiro, Brazil, 2014-2018.

We report on the occurrence and diversity of noroviruses in children (younger than 5 years old of age) from a low-income urban area in Rio de Janeiro, Brazil. Sixty-one stool specimens collected from children between 1 and 4 years old with acute diarrhoeic episodes (ADE) and non-ADE were investigated. RT-qPCR and sequencing of PCR products after conventional RT-PCR analysis were performed.

Phenotyping of Lewis and secretor HBGA from saliva and detection of new FUT2 gene SNPs from young children from the Amazon presenting acute gastroenteritis and respiratory infection.

The Histo-blood group antigens (HBGA) are host genetic factors associated with susceptibility to rotavirus (RV) and human norovirus (HuNoV), the major etiological agents of viral acute gastroenteritis (AGE) worldwide. The FUT2 gene expressing the alpha-1, 2-L- fucosyltransferase enzyme is important for gut HBGA expression, and also provides a composition of the phenotypic profile achieved through mutations occurring in populations with different evolutionary histories; as such, it can be considered a genetic population marker. In this study, Lewis and secretor HBGA phenotyping was performed using 352 saliva samples collected from children between three months and five years old born in the Amazon (Brazil, Venezuela and English Guyana) presenting AGE or acute respiratory infection (ARI), the latter considered as control samples.

Using immunoglobulin Y as an alternative antibody for the detection of hepatitis A virus in frozen liver sections.

An increasing amount of research has been conducted on immunoglobulin Y (IgY) because the use of IgY offers several advantages with respect to diagnostic testing, including its easy accessibility, low cost and translatability to large-scale production, in addition to the fact that it can be ethically produced. In a previous work, immunoglobulin was produced and purified from egg yolks (IgY) reactive to hepatitis A virus (HAV) antigens. In the present work, this anti-HAV-specific IgY was used in an indirect immunofluorescence assay to detect viral antigens in liver biopsies that were obtained from experimentally infected cynomolgus monkeys.

Comparison of two eukaryotic systems for the expression of VP6 protein of rotavirus specie A: transient gene expression in HEK293-T cells and insect cell-baculovirus system.

The VP6 protein of rotavirus A (RVA) is a target antigen used for diagnostic assays and also for the development of new RVA vaccines. We have compared the expression of VP6 protein in human embryonic kidney (HEK293-T) cells with results obtained using a well-established insect cell-baculovirus system. The recombinant VP6 (rVP6) expressed in HEK293-T cells did not present degradation and also retained the ability to form trimers.

Evaluation of murine monoclonal antibodies targeting different epitopes of the hepatitis B virus surface antigen by using immunological as well as molecular biology and biochemical approaches.

The hepatitis B virus surface protein (HBsAg) displays the major B cells antigenic determinants that can induce protective immunity and prevent the hepatitis B virus (HBV) infection, a major health problem. A panel of murine monoclonal antibodies against the HBsAg (MAb anti-HBs), raised after mice immunization with a pool of plasma of hepatitis chronic carriers, has been established. Mainly using simple immunological tools such as enzyme-linked immunosorbent assay (ELISA) and Western blot analysis, we could trace the location of the epitopes on the HBsAg determinants.

Screening of CHO cell clones expressing histidine-tagged major S hepatitis B surface protein using a semi-quantitative PCR protocol.

Different mammalian cells have been used successfully for the expression of the hepatitis B surface antigen (HBsAg). The patterns of expression of the HBsAg seem to depend on the cell type and the number of gene copies integrated into cellular genome. The expression of an HBsAg fused to histidine tag (His-HBsAg), had not been reported in mammalian cells.