Correlation between hepatitis C viral load and hepatitis C Core antigenaemia among Egyptians

Hepatitis C virus [HCV] infection is widespread in Egypt. This study compared HCV RNA with HCVcAg for the detection and quantification of viraemia among a sample of Egyptians. Sera from 80 suspected HCV-positive individuals were tested simultaneously for HCV-RNA load using real-time polymerase chain reaction [PCR] and HCVcAg level using ELISA. Of the 80 samples, 25% were HCV-RNA-negative. HCVcAg was detected in all samples: range 0.4-2462 ng/mL, mean 460 [SD 506] ng/mL. The sensitivity and specificity of HCVcAg were 96.7% and 90.9%, respectively. There was a significant correlation between serum HCV-RNA and HCVcAg levels [r = 0.4, P < 0.0001]. HCV-RNA remains the gold standard for diagnosis of active HCV infection but HCVcAg can be used where PCR is not available

Limited replication of yellow fever 17DD and 17D-Dengue recombinant viruses in rhesus monkeys

For the development of safe live attenuated flavivirus vaccines one of the main properties to be established is viral replication. We have used real-time reverse transcriptase-polymerase chain reaction and virus titration by plaque assay to determine the replication of yellow fever 17DD virus (YFV 17DD) and recombinant yellow fever 17D viruses expressing envelope proteins of dengue virus serotypes 2 and 4 (17D-DENV-2 and 17D-DENV-4). Serum samples from rhesus monkeys inoculated with YFV 17DD and 17D-DENV chimeras by intracerebral or subcutaneous route were used to determine and compare the viremia induced by these viruses. Viral load quantification in samples from monkeys inoculated by either route with YFV 17DD virus suggested a restricted capability of the virus to replicate reaching not more than 2.0 log10 PFU mL-1 or 3.29 log10 copies mL-1. Recombinant 17D-dengue viruses were shown by plaquing and real-time PCR to be as attenuated as YF 17DD virus with the highest mean peak titer of 1.97 log10 PFU mL-1 or 3.53 log10 copies mL-1. These data serve as a comparative basis for the characterization of other 17D-based live attenuated candidate vaccines against other diseases.

Uma das principais propriedades a serem estabelecidas para o desenvolvimento de vacinas seguras e atenuadas de flavivirus,é a taxa de replicação viral. Neste trabalho, aplicamos a metodologia de amplificação pela reação em cadeia da polimerase em tempo real e titulação viral por plaqueamento para determinação da replicação do vírus 17DD (FA 17DD) e recombinantes, expressando proteínas do envelope de dengue sorotipos 2 e 4 (17D-DENV-2 e 17D-DENV-4). As amostras de soros de macacos inoculados por via intracerebral ou subcutânea com FA 17DD ou 17D-DENV foram usadas para determinar e comparar a viremia induzida por estes vírus. A quantificação da carga viral em amostras de macacos inoculados por ambas as vias com FA 17DD sugere restrita capacidade de replicação com taxa não superior a 2,0 log10 PFU mL-1 ou 3,29 log10 cópias/mL-1. Os vírus recombinantes 17D-DENV mostraram-se tão atenuados quanto o vírus 17DD, tanto porRT-PCR em tempo real quanto por plaqueamento, com título médio máximo de 1,97 log10 PFU mL-1 ou 3,53 log10 cópias/mL-1. Estes dados servem como base comparativapara caracterização de outros vírus vivos atenuados, derivados do vírus 17D, candidatos a vacinas contra outras doenças.

Preparation of a neutralizing monoclonal antibody specific to serotype 8 rotavirus strains with a super-short RNA pattern.

Extensive cross-neutralization tests have identified seven serotypes of rotavirus. Recently, it has been reported that several human strains (69M, B37 and B38) with a super-short RNA pattern carry new serotype specificity (serotype 8). By using the strain 69M as an immunizing antigen, we prepared a neutralizing monoclonal antibody (designated 69M-2D). In neutralization tests using 18 human and two animal rotavirus strains with different serotype specificities, the 69M-2D antibody was found to neutralize only serotype 8 strains. Also, in an enzyme-linked immunosorbent assay (ELISA), the antibody reacted exclusively with the serotype 8 strains. Thus, the reactivity pattern of the 69M-2D antibody was serotype 8-specific. This antibody should be useful as another reagent for serotyping rotaviruses by ELISA.