FUNCTIONAL-ROLE OF HEPATITIS-C VIRUS CHIMERIC GLYCOPROTEINS IN THE INFECTIVITY OF PSEUDOTYPED VIRUS

The putative envelope glycoproteins of hepatitis C virus (HCV) likely play an important role in the initiation of viral infection. Available information suggests that the genomic regions encoding the putative e nvelope glycoproteins, when expressed as recombinant proteins in mamma lian cells, largely accumulate in the endoplasmic reticulum. In this s tudy, genomic regions which include the putative ectodomain of the E1 (amino acids 174 to 359) and E2 (amino acids 371 to 742) glycoproteins were appended to the transmembrane domain and cytoplasmic tail of ves icular stomatitis virus (VSV) G protein. This provided a membrane anch or signal and the VSV incorporation signal at the carboxy termini of t he E1 and E2 glycoproteins. The chimeric gene constructs exhibited exp ression of the recombinant proteins on the cell surface in a transient expression assay. When infected with a temperature-sensitive VSV muta nt (ts045) and grown at the nonpermissive temperature (40.5 degrees C) , cells transiently expressing the E1 or E2 chimeric glycoprotein gene rated VSV/HCV pseudotyped virus. The resulting pseudotyped virus gener ated from E1 or E2 surprisingly exhibited the ability to infect mammal ian cells and sera derived from chimpanzees immunized with the homolog ous HCV envelope glycoproteins neutralized pseudotyped virus infectivi ty, Results from this study suggested a potential functional role for both the E1 and E2 glycoproteins in the infectivity of VSV/HCV pseudot yped virus in mammalian cells. These observations further suggest the importance of using both viral glycoproteins in a candidate subunit va ccine and the potential for using a VSV/HCV pseudotyped virus to deter mine HCV neutralizing antibodies.