Search

Prevalence of hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis G virus (HGV), and hepatitis E virus (HEV) was investigated among 574 healthy blood donors in Bolivia. HCV RNA and HGV RNA in the serum were identified by a nested reverse transcription-PCR using primers derived from the 5′ untranslated region (5′ UTR). We also tested for hepatitis B surface antigen (HBsAg) and for the antibody to HEV. The results revealed that HGV RNA was present in 84 of 574 (14.6%) tested blood donors, whereas HBsAg was detected in only 2 (0.3%) donors, and no individuals positive for HCV RNA were found. Anti-HEV immunoglobulin G (IgG) was detected in 93 (16.2%) individuals and anti-HEV IgM was found in 10 (1.7%) individuals among the same population. Phylogenetic analysis of 44 HGV isolates in the 5′ UTR showed that 27 (61%) isolates were genotype 3 (Asian type) and the remaining 17 (39%) isolates were genotype 2 (United States and European type). Moreover, we obtained a full-length nucleotide sequence of the HGV genome (designated HGV-BL230) recovered from a Bolivian blood donor. The BL230 was composed of 9,227 nucleotides and had a single open reading frame, encoding 2,842 amino acid residues. Interestingly, the BL230 belonged to genotype 2 of HGV at the level of a full-length sequence, although this was classified as genotype 3 by a phylogenetic analysis based on the 5′ UTR sequence. The BL230 differed from previously reported HGV/hepatitis GB virus type C isolates by 12 to 13% of the nucleotide sequence and 4% of the amino acid sequence. Our data indicate a high prevalence of HGV in native Bolivians, and the major genotype of HGV was type 3.

Persistent hepatitis C virus (HCV) infection is a major cause of chronic liver dysfunction in humans and is epidemiologically closely associated with the development of human hepatocellular carcinoma. Among HCV components, core protein has been reported to be implicated in cell growth regulation both in vitro and in vivo, although mechanisms explaining those effects are still unclear. In the present study, we identified that members of the 14-3-3 protein family associate with HCV core protein. 14-3-3 protein bound to HCV core protein in a phosphoserine-dependent manner. Introduction of HCV core protein caused a substantial increase in Raf-1 kinase activity in HepG2 cells and in a yeast genetic assay. Furthermore, the HCV core–14-3-3 interaction was essential for Raf-1 kinase activation by HCV core protein. These results suggest that HCV core protein may represent a novel type of Raf-1 kinase-activating protein through its interaction with 14-3-3 protein and may contribute to hepatocyte growth regulation.

Using the PCR assay, we found a high prevalence of TT virus (TTV) DNA in saliva and semen from patients who were seropositive for TTV. This finding suggests that the presence of TTV in body fluids other than serum may affect the routes of viral transmission.