Compositions and methods of use are provided to boost a primed immune response to HIV. More specifically, the present invention relates to vaccine compositions comprising an HIV- protein boost or an MVA-expressed Env protein and methods of use. Exemplary HIV proteins for protein boosts include proteins such as gp120 proteins B.63521Δ11mutC and full-length single chain (FLSC), which has been modified to stabilize a CD4-induced Env structure. Exemplary MVAs expressing secreted Methods of administration and dosing regimens are also provided.
