Second AIDS vaccine approved for testing.

Second AIDS vaccine approved for testing

A second potential AIDS vaccine was approved last week by federal officials for human testing in the United States.

The vaccine was developed by Seattle-based Oncogen, a division of the Bristol-Myers Co. It will be given to 30 healthy homosexual males beginning in January at Seattle's Pacific Medical Center, according to study coinvestigator Ann Collier of the University of Washington School of Medicine. Another group of 30 controls will be involved in this phase of the study, which will examine the vaccine's safety and how it might influence the immune response.

Testing of the first potential AIDS vaccine, developed by MicroGeneSys, Inc., of West Haven, Conn., was approved by the Food and Drug Administration (FDA) last summer (SN: 8/22/87, p.116). Inoculation of human volunteers, who are predominantly homosexual males, began in September at the National Institute of Allergy and Infectious Diseases in Bethesda, Md. The only side effect so far has been redness near the inoculation site, which is typical for inoculations, says MicroGeneSys President Frank Volvovitz.

Both vaccines will expose volunteers to similar viral proteins found in the "envelope' structure surrounding the human immunodeficiency virus (HIV), which can lead to fully developed AIDS. The proteins will not cause HIV infection, researchers say, but should stimulate an effective immune response that protects against future HIV infection.

The vaccines will introduce viral proteins differently to the body. The Bristol-Myers experimental vaccine, called HIVAC-1e, is made from the vaccinia virus, which has been used to manufacture the smallpox vaccine. In the case of the potential AIDS vaccine, researchers have altered the vaccinia virus by inserting a gene coding for the HIV viral protein gp 120. The hope is that after the vaccine enters the body, the gene will use the machinery of invaded cells to make gp 120 proteins, which will then appear on the cell surface and be recognized by the body's immune system.

To make the MicroGeneSys vaccine, researchers inserted a gene coding for gp 160 into a virus that infects moths and butterflies, placed the virus into cultures containing insect cells and produced a large quantity of the viral protein, which is used as the vaccine.

The studies of these and other vaccines will determine which triggers the best immune response, says Gerald Quinnan, director of the FDA's division of virology. In the "insect' approach, the protein will be floating freely in tissue fluids, while in the vaccinia approach, it will be on cell surfaces.

If the vaccines' safety and immune response are established, their ability to prevent HIV infection will then be studied.