Molecular Genetics Of Eukaryotic Cells And Their Viruses

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Abstract

Most lentivirus vaccine studies have utilized envelope glycoproteins from one virus isolate; protective efficacy has usually been assessed using a homologous virus challenge (i.e. the virus isolate used to challenge animals contains the same gp120 used for immunization). We have evaluated a vaccine regimen, based solely on envelope glycoproteins, which compared individual or mixtures of both recombinant vaccinia viruses and gp120 boosts followed by challenge with an SIV/HIV chimeric virus to assess whether it is possible to elicit a broader neutralizing antibody response. One arm of the polyvalent vaccine protocol constituted a heterologous challenge because the envelope glycoprotein carried by the challenge virus was not included envelope glycoprotein cocktail. Although several animals produced high levels of neutralizing antibodies following immunization and sterilizing protection following intravenous SHIV inoculation, this response was limited to vaccinated monkeys in the homologous arms of the experiment. Macaques in the heterologous arm failed to generate neutralizing antibodies against the challenge virus but were more resistant to the SHIV infection due to cell mediated responses elicited by the vaccine.