Abstract: This invention is directed toward nucleic acids encoding self-assembled, non-infectious, non-replicating, immunogenic retrovirus-like particles comprising modified HIV-1 genomes devoid of long terminal repeats and containing nucleotide sequences encoding chimeric envelope glycoproteins. Retrovirus-like particles containing chimeric envelope glycoproteins were expressed in mammalian cells by using inducible promoters. One preferred embodiment discloses the engineering of a series of expression vectors in which a synthetic oligomer encoding gp120 residues 306 to 328 (amino acids YNKRKRIHIGP GRAFYTTKNIIG) from the V3 loop of the MN viral isolate was inserted at various positions within the endogenous HIV-1.sub.LAI env gene. Expression studies revealed that insertion of the heterologous V3(MN) loop segment resulted in the secretion of fully assembled HIV-like particles containing chimeric LAI/MN envelope glycoproteins. Both V3 loop epitopes were recognized by loop-specific neutralizing antibodies.

Abstract: This invention is directed toward self-assembled, non-infectious, non-replicating, immunogenic retrovirus-like particles comprising modified HIV-1 genomes devoid of long terminal repeats and containing nucleotide sequences encoding chimeric envelope glycoproteins. Retrovirus-like particles containing chimeric envelope glycoproteins were expressed in mammalian cells by using inducible promoters. One preferred embodiment discloses the engineering of a series of expression vectors in which a synthetic oligomer encoding gp120 residues 306 to 328 (amino acids YNKRKRIHIGP GRAFYTTKNIIG) from the V3 loop of the MN viral isolate was inserted at various positions within the endogenous HIV-1.sub.LAI env gene. Expression studies revealed that insertion of the heterologous V3(MN) loop segment resulted in the secretion of fully assembled HIV-like particles containing chimeric LAI/MN envelope glycoproteins. Both V3 loop epitopes were recognized by loop-specific neutralizing antibodies.

Abstract: This invention is directed toward diagnostic kits and antigens useful for the detection of viral antigens in a test sample. The kit contains antigens obtained from self-assembled, non-infectious, non-replicating, immunogenic retrovirus-like particles comprising modified HIV-1 genomes devoid of long terminal repeats and containing nucleotide sequences encoding chimeric envelope glycoproteins. One preferred embodiment discloses the engineering of a series of expression vectors in which a synthetic oligomer encoding gp120 residues 306 to 328 (amino acids YNKRKRIHIGP GRAFYTTKNIIG) from the V3 loop of the MN viral isolate was inserted at various positions within the endogenous HIV-1.sub.LAI env gene. Expression studies revealed that insertion of the heterologous V3(MN) loop segment resulted in the secretion of fully assembled HIV-like particles containing chimeric LAI/MN envelope glycoproteins. Both V3 loop epitopes were recognized by loop-specific neutralizing antibodies.