View clinical trials related to Vaccinia.
Filter by:To evaluate, in healthy HIV-1 seronegative vaccinia-immune and vaccinia-naive volunteers, the safety and immunogenicity of an HIV-1 candidate vaccine (TBC-3B) consisting of a live recombinant vaccinia virus expressing the env, gag, and pol genes of HIV-1 IIIB strain. To evaluate the potential of boosting with one of a variety of HIV-1 recombinant subunit, peptide, or pseudovirion vaccines, if available, to augment the immune responses of the vaccinees. Antigenic drift, defined as the genetic variation of the HIV-1 envelope gene that results in antigenic variation during natural infection, may confound attempts to achieve protective immunity using a vaccine based solely on HIV-1 envelope proteins. Inclusion of conserved core and polymerase proteins along with envelope protein in a candidate vaccine may address some of the problems with antigenic variability. A prime-boost immunization approach using a novel priming immunogen expressing env, gag, and pol genes of the HIV-1 IIIB strain will be attempted in this study.
Primary: To determine in healthy volunteers whether priming with a vaccinia HIV-1 gp160 envelope gene recombinant vaccine (HIVAC-1e) followed by boosting with one of two subunit recombinant HIV-1 envelope vaccines (Env 2-3 and gp120) provides enhanced immunogenicity compared to vaccination with the gp120 subunit vaccine alone. (Per 10/01/92 amendment, boosts with VaxSyn (gp160) were eliminated.) To evaluate the immunogenicity of one versus two priming doses of HIVAC-1e prior to a boost with gp120. To compare the relative immunogenicity of the three subunit vaccines when administered as boosters. Secondary: To examine the safety of administering the individual subunit vaccines in combination with HIVAC-1e and the safety of administering the gp120 subunit vaccine alone. In a previous study of candidate HIV vaccines, the evidence suggested that administration of a booster vaccination with a different vaccine preparation may produce a better immune response than administration of HIVAC-1e vaccine alone.
Evaluation of the safety and immunogenicity (immunological reactivity) of HIVAC-1e vaccine. An additional goal is to determine which dose level of vaccine might be most effective. Specific questions to be addressed in this part of the study include: Are there adverse reactions to gp160 vaccine when given to vaccinees previously immunized with a vaccinia-recombinant? Does gp160 vaccination of prior HIVAC-1e vaccine result in stimulation of neutralizing antibody and other humoral immune responses? Does vaccination with gp160 enhance the development of cell-mediated immune responses in HIVAC-1e vaccinees? Is the magnitude of immune response to gp160 booster immunization greater following priming with GP160 recombinant vaccinia (HIVAC-1e) vaccination than priming with three doses of purified recombinant gp160? AMENDED: An 80 mcg dose of gp160 has been chosen for the booster because this dose has been shown to be safe and immunogenic in previous trials and allows comparison of the late boost in this protocol with the late boost in the protocol in which patients were primed with three doses of gp160. Original design: HIVAC-1e vaccine is a preparation of the envelope protein of HIV (the virus that causes AIDS). The protein is produced by genetic modification in vaccinia virus. The purpose of a vaccine is to produce an artificially increased immunity to a particular disease, in this case, AIDS. Since there is no known cure for AIDS, the control of this disease necessitates the development of effective prevention such as vaccines.
Primary: To determine whether additional boosting with soluble recombinant gp160 vaccine (VaxSyn) after priming with a vaccinia-HIV envelope recombinant (HIVAC-1e) provides a significant advantage in the degree and duration of immunogenicity. Secondary: To learn more about the safety of the combination use of the two HIV envelope vaccines in the study (VaxSyn and HIVAC-1e). Recent Phase I trials conducted at the AIDS Vaccine Units have shown that antibodies have persisted in most recipients for 6 months after boosting, and responses seem significantly higher and more persistent than responses achieved by just two doses of soluble protein vaccine alone or two doses of HIVAC-1e alone. This study tests in a previously recruited cohort of volunteers whether additional boosting with soluble recombinant gp160 results in increased immunogenicity of longer duration.
To determine if priming (giving the first vaccination) with a vaccinia recombinant (HIVAC-1e) provides a significant advantage in immunogenicity (production of antibodies) compared to priming with a soluble recombinant protein (gp160); to learn more about the safety of the combination use of the two HIV envelope vaccines utilized in the study. Recent studies at the AIDS vaccine units have shown the safety of two candidate HIV vaccines, HIVAC-1e and gp160. Specific questions to be addressed in this part of the study include: Does combination vaccination result in a synergistic (added) response not predicted by just the addition of a second vaccination, and does this synergism depend on the unique priming effect of a vaccinia recombinant, or will any combination do?