Isolated anti-cancer peptides are disclosed which are characterized by the amino acid sequences TLTSGGGAIALPPSMAAPPLGPVAPLTGAIHAPTXG (SEQ ID NO: 1) TLSTATGGAIPPVAAMPPGLVAPTHGPAIHP (SEQ ID NO: 2) CCATSGPCGAVMILTPHLTA (SEQ ID NO: 5) MTLTTGSGAIAPAMPPGLPPHTGAIHAPM (SEQ ID NO: 4) and NXVPVSVEGYXQITLDSITX (SEQ ID NO: 3) and a significant in vitro binding affinity for gp96. The peptides exhibit anti-tumor, anti-cancer activity in vivo. Also disclosed is an isolated antiviral peptide characterized by the amino acid sequence GDEPLENYLDTEYF (SEQ ID NO: 6) and a significant in vitro binding affinity for HIV-1 gp 120 and gp 41, and human CD4 cells. The peptide exhibits anti-retroviral activity in vivo, particularly anti-HIV-1 activity.
