Antigenicity of a candidate varicella-zoster virus glycoprotein subunit vaccine

A 1642 bp DNA fragment, encoding the N-terminal region and 511 amino acid residues of varicella-zoster virus (VZV) glI gene, was inserted into vaccinia virus genome. The expression of recombinant vaccinia virus (designated VVTgpI-511) yielded the synthesis of a 60 kDa protein species which was processed to a secretory 76 kDa polypeptide (designated TgpI-511). The antigenicity of this protein was examined by subcutaneous inoculation of one rabbit with 100 micrograms purified TgpI-511 in the Ribi adjuvant system. The animal was boosted 3 weeks after the initial inoculation and antisera were tested 7 days after the last injection by immunoprecipitation and neutralization tests. The results showed that rabbit antibodies to TgpI-511 (RAnti-TgpI-511) were reactive with purified TgpI-511 as well as native gpI in VZV-infected cells. In addition, TgpI-511 was capable of eliciting complement-dependent VZV neutralizing antibodies. These results suggested that the purified preparation of TgpI-511 may have the potential to be used as a candidate VZV subunit vaccine.