Presence of neutralizing antibodies(Nab) to 5 laboratory strains of human immunodeficiency virus type-1 (HIV-1) was studied and compared in the sera of eight macaca (Macaca fascicularis) after the third and fourth immunizations with multi-epitope polypeptide TAB9, emulsified with adjuvant Montanide ISA 720. Four animals were inoculated 1 mg and the others 200 micrograms, 2 animals were used as controls and injected only with adjuvant. Although the presence of neutralizing antibodies to homologous strains of HIV-group group B was confirmed in most animals after immunization through antigen p24 capture ELISA (DAVIH-Agp24, Cuba), no statistically significant differences were found neither in titers caused by antigen concentrations nor in the responses after the third and fourth immunizing doses. Controls did not develop neutralizing antibodies.