Identification of a virus similar to hepatitis B virus in non-A non-B hepatitis]

Hepatitis B virus-like particles (including DANE particles) with DNA polymerase activity but negative for HBs Ag have been identified in NON-A, NON-B hepatitis sera positive for HC Ag. Although specifically associated with the particles, HC Ag is not a surface antigen of the hepatitis C virus identified here for the first time. The relationship of this agent with HBV seems obvious, and deserves further study.     

Protein kinase activity in Escherichia coli]

When growing E. coli in a minimal medium, at least four proteins from the soluble fraction and one ribosome-associated protein are found phosphorylated at the level of their threonine and serine residues.     

4-Thiouridine and photoprotection in Escherichia coli K 12]

A high level of protection is observed in the Escherichia coli K 12 strain AB 1157 rec A 1 nuv+ whose transfer RNA contains 4-thiouridine. In contrast, the photoprotection level is low and observed at higher doses in a strain which differs from the former by a single mutation, nuv-, (lack of 4-thiouridine). This nucleoside is therefore an important chromophore leading to photoprotection. This conclusion is corroborated by the similarity of the action spectra for 8-13 link formation in tRNA and for photoprotection.     

Non-A non-B hepatitis virus: demonstration of a double antigenic and structural kinship with hepatitis B virus

Major antigenic identity has been demonstrated by immunodiffusion between the Ag described by Shirachi and confirmed by us (NANB/e) in the serum on non A non B hepatitis and the HBe/3 specificity of hepatitis B virus (HBV). A second Ag (NANB/c) linked to the core of a new virion morphologically similar to HBV and also associated with ADN polymerase activity as recently described, has been identified and purified from an infected liver. This NANB/c Ag also cross reacts with HBc Ag. These results confirm that HBV and the NANB virus defined here belong to the same new class of DNA viruses.     

The translocation motif of hepatitis B virus improves protein vaccination

Cell-penetrating peptides (CPPs) have been shown to improve antigen loading of dendritic cell vaccines. Here we asked whether fusion of a CPP to a protein improves its immunogenicity when this fusion protein is directly applied as vaccine. We used the cell-penetrating translocation motif (TLM) derived from the hepatitis B virus, because no size limitation of cargos has been observed. Increased immunogenicity was observed when TLM was fused to ovalbumin (TLM-ova). TLM-ova was found to be superior to ova in inducing proliferation and cytotoxicity of ova-specific CD8+ T cells in vitro and in vivo. Using ovalbumin-expressing thymoma cells (EG7-ova), an improved anti-tumor immune response was observed for TLM-ova vaccination versus vaccination with ova. Moreover, TLM-ova vaccination induced a higher titer of anti-ovalbumin IgG2a antibodies compared to ova. These data demonstrate that CPP-protein vaccines can improve cellular as well as humoral immune responses. Received 16 November 2005; received after revision 12 December 2005; accepted 10 January 2006 †These authors contributed equally to this work