Efficient human immunodeficiency virus (HIV)-1 Gag-Env pseudovirion formation elicited from mammalian cells by a canarypox HIV vaccine candidate

Canarypox viruses undergo abortive replication in mammalian cells. Despite this restriction on replication in mammalian cells, significant immune resp onses have been shown in animals and in humans receiving recombinant canary pox vaccine vectors expressing heterologous immunogens, A recombinant canar ypox vaccine candidate (vCP205), which expresses human immunodeficiency vir us (HIV)-1 Gag, Env, and protease proteins, is presently under investigatio n in phase I and phase II human trials in the United States and elsewhere. In this study, the ability of vCP205 to elicit HIV Gag-Env pseudovirion for mation in avian and mammalian cells was investigated. Gag-Env pseudovirions were produced from both avian and mammalian cell lines infected by this va ccine vector. A subset of mammalian cells was identified in which pseudovir ion production and release was very efficient, surpassing the production fr om infected avian cells. The production of Gag-Env pseudovirions by canaryp ox HIV vaccine vectors may have important implications for future HIV vacci ne design.