Abstract: Compositions and methods based on the use of mutated HIV-1 gp120 polypeptides having amino acid substitutions at positions 61, 105, 108, 375, 474, 475 and 476 are described. These mutated HIV-1 gp120 polypeptides, which make the HIV env protein more amenable to adopt specific conformations when contacted with gp120 ligands, may be useful as vaccines or tools to identify and characterize agents modulating HIV infection.

Abstract: Stable immunogens comprising portions of the inner domain (ID) of the Human Immunodeficiency Virus (HIV-1) gp120 protein are provided. These ID immunogens selectively present the gp120 C1/C2 region in its CD4-bound state within a minimal structure. These ID immunogens can be used to vaccinate subjects against infection with HIV, the causative agent of Acquired Immunodeficiency Syndrome (AIDS). The immunogens can also be used as targets in screening to identify small molecule or peptide inhibitors that block HIV-1 viral entry and attachment steps, and as probes for identifying gp120 C1/C2 region-specific antibodies.

Abstract: Fusion proteins comprising a portion of the HIV-1 Env protein (gp120 and gp140) and single-chain fragment V regions (ScFv) of an enhancing antibody that exhibits binding specificity for HIV-1 Env protein are disclosed that may serve in immunogenic formulations for vaccination against HIV-1 infection, as well as methods of generating an immune response using the fusion proteins.

Abstract: Stable immunogens comprising portions of the inner domain (ID) of the Human Immunodeficiency Virus (HIV-1) gp120 protein are provided. These ID immunogens selectively present the gp120 C1/C2 region in its CD4-bound state within a minimal structure. These ID immunogens can be used to vaccinate subjects against infection with HIV, the causative agent of Acquired Immunodeficiency Syndrome (AIDS). The immunogens can also be used as targets in screening to identify small molecule or peptide inhibitors that block HIV-1 viral entry and attachment steps, and as probes for identifying gp120 C1/C2 region-specific antibodies.

Abstract: Fusion proteins comprising a portion of the HIV-1 Env protein and ScFv of an enhancing antibody are disclosed that may serve in immunogenic formulations for vaccination against HIV-1 infection. A broadly neutralizing antibody and engineered bi-/tri-specific anti-HIV-1 antibodies that may serve in the prevention and/or treatment of HIV-1 infections in a subject are also disclosed, as well as methods of using the fusions proteins and antibodies.