A method for designing a HIV Env gene insert with a nucleotide bias characteristic of Vesicular Stomatitis Virus to make it compatible with a Vesicular Stomatitis Virus host vector comprising: a. modifying the protein sequence of the Env gene insert by substituting it with one or more sequences from VSV glycoprotein selected from the group consisting of the VSV G signal sequence (secretory signal), the membrane proximal extracellular stem domain, the transmembrane domain and the intracellular cytoplasmic domain, b. addition of cis-acting RNA sequences that promote efficient translation, and c. designing the gene insert with a nucleotide sequence that resembles a base composition of the host vector by making modifications including: - Interrupting homopolymer sequences >5 nucleotides (CCCCC, GGGGG) by substitution of at least one synonymous codon; - Interrupting homopolymer sequences >4 nucleotides (AAAA, TTTT) by substitution with at least one synonymous codon; - Modifying the 5' end of the coding sequences to include a Kozak translation initiation sequence (aggaGCCACCATG); - Adding an optimal translation termination signal TAAag to the 3' end of the coding sequences; - Interrupting RNA instability elements similar to UUAUUUAUU by replacing sequence with synonymous codons; - Interrupting potential polyadenylation signals (AAUAAA) by substitution with synonymous codons; - Removing potential T7 polymerase terminators: cTGAg, gacTAAag, ctTAAac and gacTAAat to prevent inhibition of recombinant VSV rescue from cloned DNA; - Using a commercial mRNA splice site prediction software tool to predict the potential splice sites and substituting synonymous codons. a. modifying the protein sequence of the Env gene insert by substituting it with one or more sequences from VSV glycoprotein selected from the group consisting of the VSV G signal sequence (secretory signal), the membrane proximal extracellular stem domain, the transmembrane domain and the intracellular cytoplasmic domain, b. addition of cis-acting RNA sequences that promote efficient translation, and c. designing the gene insert with a nucleotide sequence that resembles a base composition of the host vector by making modifications including: - Interrupting homopolymer sequences >5 nucleotides (CCCCC, GGGGG) by substitution of at least one synonymous codon; - Interrupting homopolymer sequences >4 nucleotides (AAAA, TTTT) by substitution with at least one synonymous codon; - Modifying the 5' end of the coding sequences to include a Kozak translation initiation sequence (aggaGCCACCATG); - Adding an optimal translation termination signal TAAag to the 3' end of the coding sequences; - Interrupting RNA instability elements similar to UUAUUUAUU by replacing sequence with synonymous codons; - Interrupting potential polyadenylation signals (AAUAAA) by substitution with synonymous codons; - Removing potential T7 polymerase terminators: cTGAg, gacTAAag, ctTAAac and gacTAAat to prevent inhibition of recombinant VSV rescue from cloned DNA; - Using a commercial mRNA splice site prediction software tool to predict the potential splice sites and substituting synonymous codons. - Interrupting homopolymer sequences >5 nucleotides (CCCCC, GGGGG) by substitution of at least one synonymous codon; - Interrupting homopolymer sequences >4 nucleotides (AAAA, TTTT) by substitution with at least one synonymous codon; - Modifying the 5' end of the coding sequences to include a Kozak translation initiation sequence (aggaGCCACCATG); - Adding an optimal translation termination signal TAAag to the 3' end of the coding sequences; - Interrupting RNA instability elements similar to UUAUUUAUU by replacing sequence with synonymous codons; - Interrupting potential polyadenylation signals (AAUAAA) by substitution with synonymous codons; - Removing potential T7 polymerase terminators: cTGAg, gacTAAag, ctTAAac and gacTAAat to prevent inhibition of recombinant VSV rescue from cloned DNA; - Using a commercial mRNA splice site prediction software tool to predict the potential splice sites and substituting synonymous codons.