Eastman D, Sheppard HW, Dondero D, Ivanoff R, Ackers M, McDougal S, Parekh B, La-Ong S, Berman PW; International Conference on AIDS.
Int Conf AIDS. 2000 Jul 9-14; 13: abstract no. MoPeA2135.
D. Eastman, VaxGen, Inc., 1000 Marina Blvd, Suite 200, Brisbane, CA 94005-1841, United States, Tel.: +1 650 624 2410, Fax: +1 650 624 2401, E-mail: deastman@vaxgen.com
Backgrounds: One major concern in HIV-1 vaccine trials is the possibility that vaccinated volunteers will test falsely positive in clinical assays for HIV infection on the basis of antibodies induced by vaccine antigen. Historically, the risk for false-positivity in studies using gp120 vaccines was low, since few assays kits contained measurable amounts of gp120. However, newer assays, designed to detect antibodies to both HIV-1 and HIV-2, are reported to be supplemented with synthetic or recombinant HIV envelope peptides. Based on these changes, we investigated whether volunteers immunized with candidate AIDS vaccines, containing recombinant envelope glycoprotein, gp120, developed antibodies reactive with antigens present in currently available diagnostic assays. Methods: Antisera were obtained from volunteers participating in a Phase I or Phase I/II clinical trials of AIDSVAX B, AIDSVAX B/B or AIDSVAX B/E. The clinical trials conducted in multiple sites in the U.S. and Bangkok, Thailand. Four clinical HIV diagnostic assays were evaluated. All assays were performed according to the manufacturers instructions. Specimens found to be ELISA reactive were tested by immunoblot to confirm HIV infection. Results: Commercial HIV ELISA kits containing synthetic or recombinant gp120 derived polypeptides yield a higher false positive rate (range up to 25%) than HIV assay kits that lack rgp120 derived polypeptides (range up to 3%). Conclusions: There is little, if any chance that participants in gp120 vaccine trials could be mis-classified as being HIV infected, provided positive HIV ELISA is followed by confirmatory immunoblot. However, if ELISA assays alone are used to detect HIV infection (as is the case in some countries), the chance of mis-classification is increased. Clinical laboratories need to consider vaccine induced immunoreactivity in the design and selection of HIV assay kits.
Publication Types:
Keywords:
- AIDS Vaccines
- AIDSVAX
- Acquired Immunodeficiency Syndrome
- Antibodies
- Biological Assay
- Clinical Trials as Topic
- Evaluation Studies
- HIV
- HIV Antigens
- HIV Envelope Protein gp120
- HIV Infections
- HIV Seronegativity
- HIV Seropositivity
- HIV-1
- HIV-2
- Thailand
- United States
- Vaccines
- analysis
- diagnosis
- immunology
- methods
Other ID:
UI: 102237682
From Meeting Abstracts