Vaccine Candidates Prevent Development Of AIDS In Monkeys

BioStatum, Inc. claims its gene-attenuated virus vaccine candidates prevent the development of AIDS in monkeys. A report, published in the November issue of the Journal of Virology, documents the efficacy of two gene-attenuated virus vaccines that protect macaque monkeys against exposure to an HIV-1-based virus. Dr. Opendra ("Bill") Narayan, director of the Marion Merrell Dow Laboratory of Viral Pathogenesis at the University of Kansas Medical Center, conducted the study.

Narayan and his colleagues tested the protective effects of the viral vaccines by exposing the immunized monkeys to a highly pathogenic hybrid virus named KU-SHIV-1, which Narayan developed three years ago. KU-SHIV-1's inner structure is derived from SIV (simian immunodeficiency virus) and the virus' outer surface, or envelope, is derived from HIV-1 (human immunodeficiency virus). The composite virus leads to full- blown AIDS in macaque monkeys within six months of infection, whether given intravenously, orally or intravaginally.

"This animal model has proved ideal for evaluating the efficacy of vaccines against both intravenous and sexually-transmitted HIV," says Narayan, a member of BioStratum's scientific advisory board. "The infection and disease induced by KU-SHIV-1 in macaque monkeys is nearly identical to that seen in humans infected with HIV-1, but compressed into a much shorter time period. In comparison, other models used to test AIDS vaccines have been based on the SIV system, which induces an infection and disease quite differently than that caused by HIV."

BioStratum's viral vaccine candidates are based on KU-SHIV-1. To make the vaccine, scientists deleted specific disease-producing genes identified during the development of KU-SHIV-1. Because of the gene deletions, the resulting attenuated SHIV is crippled and unable to cause disease. However, the attenuated virus retains the ability to infect and induces an immune response that protects against future exposure to KU-SHIV-1.

In the study reported by Narayan, 11 out of 12 macaque monkeys given the novel gene-attenuated viral vaccines did not develop AIDS when exposed intravaginally to KU-SHIV-1, whereas animals that did not receive the vaccine developed AIDS when exposed to the same virus.

"We are currently treating KU-SHIV-1-infected monkeys with anti-HIV drugs to control the viral infection," Narayan says. "Then we administer the vaccine to induce an HIV-fighting immune response. Our goal is to build a therapy regimen around the vaccine that would reduce the amount of anti-HIV drugs needed to keep the levels of the virus in check."

The Journal of Virology paper, titled "Oral Immunization of Macaques with Attenuated Vaccine Virus Induces Protection Against Vaginally Transmitted AIDS" (Vol. 72 no. 11, p.9069), is co-authored by 13 scientists from the University of Kansas Medical Center, the National Cancer Institute and the Yerkes Regional Primate Center.

BioStratum has also formed a new subsidiary, TheraVax, Inc., to expand its current development efforts for a novel treatment for HIV infections, consisting of a viral vaccine administered in combination with anti-HIV drugs. All HIV- related technology currently licensed from the University of Kansas Medical Center to BioStratum, including a proprietary HIV-1-based AIDS animal model and the candidate gene-attenuated virus vaccines, will be transferred to TheraVax for development and commercialization.

For more information: Dr. Archie W. Prestayko, president and CEO, or Dr. J. Wesley Fox, executive vice president, BioStratum, Inc., 2605 Meridian Parkway, Suite 120, Durham, NC 27713, USA. Telephone: 919-572-6515. Fax: 919-544-5425.