The present invention relates to &bgr;-hCG, particularly &bgr;-hCG proteins having a sequence of amino acids 41-54, 45-54, 47-53, 45-57 and 45-58 and analogs and derivatives thereof. The invention further relates to methods of treatment and prevention of HIV infection by administration of a therapeutic compound of the invention. Such therapeutic compounds include hCG, &bgr;-hCG and &bgr;-hCG peptides, analogs and derivatives of hCG, &bgr;-hCG and &bgr;-hCG peptides, and nucleic acids encoding hCG, &bgr;-hCG and &bgr;-hCG peptides. In a preferred embodiment, &bgr;-hCG peptides, particularly &bgr;-hCG peptides of amino acids 47-53, 45-57 or 45-58 are administered to a subject for treatment or prevention of HIV infection in that subject. The invention also provides methods for screening hCG preparations for activity in treating or preventing HIV infection. Pharmaceutical compositions and methods of administration of Therapeutics are also provided.