SAFETY AND IMMUNOGENICITY OF UBI HIV-1(MN) OCTAMERIC V3 PEPTIDE VACCINE ADMINISTERED BY SUBCUTANEOUS INJECTION

Twenty-four HIV-seronegative men, at high risk of HIV infection, were recruited into a phase I/II safety and immunogenicity trial of a proto type HIV vaccine, The immunogen was a synthetic, monovalent, octameric HIV-1(MN) V3 peptide in an aluminum hydroxide (alum) adjuvant. The va ccine had been evaluated previously using a standard 0-, 1-, 6-month i ntramuscular schedule and was found to stimulate neutralizing antibody in 60-90% of volunteers, Participants were randomized to receive eith er 500 mu g (n = 10; high dose) or 100 mu g (n = 10; low dose) of immu nogen or placebo (alum alone; n = 4) at 0, 1, and 6 months by subcutan eous injection, Responses to the immunogen were evaluated by enzyme-li nked immunosorbent assay (ELISA) detectable antibody and by proliferat ive responses, Safety was monitored by both clinical assessment and re gular review with a clinical psychologist. No serious adverse experien ces were observed following administration of the assigned medication. One individual (placebo) seroconverted while on study, following expo sure to HIV. After the vaccination course only four individuals (three high dose and one low dose) had ELISA-detectable antibody against the immunogen, In the evaluable samples, from 19 volunteers, only 7 vacci ne recipients (3 high dose and 4 low dose) had demonstrable lymphoprol iferative responses to preparations of the immunogen, Subcutaneous adm inistration of this candidate vaccine was safe but did not result in u niform or robust immunological responses.