A progress report on AIDS research

A Progress Report On AIDS Research

The scientist is hunched over his test tube, intent on the cloudy contents. Suddenly he jumps up, arms raised in exultation, and shouts, "Eureka! I've found it!'

Isn't that how it's supposed to happen? Maybe so, but that's what movies--not science--are made of. It's clear that discovery of a vaccine or cure for AIDS will not be signaled by one triumphant eureka. Rather, success will be the culmination of many small, often tedious, steps in medical research. Given the ravages of this disease and its relentless spread, the rate of progress may seem painfully slow.

But in fact there has been an amazing amount of research-- and progress--on acquired immune deficiency syndrome. According to Dr. Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID) and coordinator for AIDS research at the National Institutes of Health (NIH), scientists have learned "more about the nature of the AIDS virus, its component structures and their functions, and its mechanisms of pathogenesis [disease development] in a shorter period of time than . . . any other infectious agent.' Still, this tiny virus, which barely qualifies as a life form, remains undefeated in the war it has waged with man.

The AIDS virus (HIV, or human immunodeficiency virus) belongs to a family of recently recognized "retroviruses.' Its outer shell, or envelope, surrounds a protein core that protects its genetic material, RNA (ribonucleic acid). To infect a cell, the virus attaches to a receptor on the cell's surface, enters the cell, sheds its outer coat, and releases its RNA. Then, using an enzyme it makes called reverse transcriptase, the virus converts its RNA into DNA (deoxyribonucleic acid). The viral DNA becomes integrated into the cell DNA. When the cell divides, the altered DNA produces viral messenger RNA (mRNA) that codes for new viral proteins. In essence, the infected cell becomes a virus factory, and the new viruses go on to infect other cells. This may not happen as soon as a cell is infected; the virus may remain latent for months or years without causing detectable harm.

The prime targets of the AIDS virus are T4 lymphocytes, white blood cells that orchestrate the body's immune response to invading germs. This presents an enormous problem because, as Fauci explains, "the first thing that the virus attacks is the very cell that's supposed to protect the body against it. So, you're essentially wiping out the defense system of the body on the first day of the war.' The virus can also infect brain cells, causing memory loss, loss of coordination, partial paralysis, or mental disorders.

A cure for AIDS will likely require two types of drugs used together: an anti-viral agent to kill the virus and an immune enhancer to help rebuild the damaged immune system. An intense search is on around the globe for those elusive compounds and for a vaccine that will prevent new infections. Last June, more than 7,000 people from approximately 70 countries gathered in Washington, D.C., to exchange information at the Third International Conference on AIDS, described in a Washington Post article as the "largest international scientific gathering ever devoted to one disease.' Some of the reports presented on drug and vaccine research were hopeful, some discouraging, and others controversial. Undisputed, however, was the extraordinary energy being expended on coming to grips with all aspects of the disease.

In this country, the U.S. Public Health Service leads the federal effort. From 1984 through 1986, PHS spent close to $93 million on AIDS drug and vaccine research. In 1987, nearly $145 million will be spent, and President Reagan's 1988 budget request for these activities is just over $185 million.

NIH has been conducting research on AIDS at its Bethesda, Md., campus near Washington, D.C., since the disease was first recognized in 1981. Besides its "intramural' work by NIH scientists, the agency supports studies in medical institutions around the country. NIAID has established 19 AIDS treatment evaluation units engaged in human (clinical) testing of experimental drugs. AIDS clinical study groups will soon be set up so that doctors outside large cities can participate in drug development and testing. In 1986, NIAID established National Cooperative Drug Discovery Groups in five medical centers. The groups comprise scientists from various disciplines who work together to find new approaches to drug development. More than 10 new groups will be funded by the end of 1987, and similar National Cooperative Vaccine Development Groups will be set up in 1988.

Most of the AIDS anti-viral drugs target the virus at the point where RNA is converted to DNA by blocking the action of reverse transcriptase. Among these drugs are zidovudine (also known as AZT)--the only drug currently approved by FDA for treating AIDS--and dideoxycytidine (DDC), now in clinical trials.