Researchers have developed an AIDS drug that apparently cankill cells infected with any strain of HIV.

The drug, a bispecific antibody, is designed to bring a patient'skiller T cells directly to HIV-infected cells. The drug alsotriggers the T cells to kill the infected cells.

Patients with AIDS have low numbers of killer T white bloodcells, but those they have are active.

Scientists at the University of California, San Francisco, ChironCorp. and Genentech Inc. worked together to develop anantibody that would ensure that killer T cells got close enoughto HIV-infected cells to kill them.

The research team reported Saturday in the Proceedings of theNational Academy of Sciences that the bispecific antibody kills40 percent to 70 percent of HIV-infected cells in the test tube.

The bispecific antibody is so called because it recognizes twoantigens simultaneously. One-half of the antibody binds to theCD3 antigen on killer T cells, activating those cells to kill virallyinfected cells. The other half of the antibody consists ofGenentech's CD4 protein-antibody conjugate.

CD4 binds to the viral envelope protein gp120 found on thevirus and on the surface of HIV-infected cells. HIV strains havea variety of gp120 proteins, but all must bind CD4 to beinfectious. Thus, the scientists believe their bispecific antibodywill kill cells infected by any HIV strain.

Matthias Wabl, director of the study, predicted that patientswill only need small quantities of the bispecific antibody. Hislab is scaling up production of the drug for animal and humanstudies. He cautions that only clinical testing will determinewhether the drug will stop HIV infection, and pointed out thatit is unknown whether removing HIV is sufficient to stop theprogression of AIDS once the infection has taken place.

A Genentech spokeswoman told BioWorld that the South SanFrancisco, Calif., company has rights of first refusal to licenseany patent rights that UCSF acquires on the technology. AChiron spokesman said the Emeryville, Calif., company has norights to the development.

-- Carol Talkington Verser, Ph.D. Special to BioWorld

(c) 1997 American Health Consultants. All rights reserved.