Every few months doctors from medical research centers seem to announce another major breakthrough in the search to cure AIDS. Standing before a group of anxious reporters, the doctors explain in layman's terms the genetic and protein makeup of the AIDS virus which has the popular reputation as one of the deadliest diseases known.

Since the first American AIDS case was diagnosed in 1979, doctors have made the Harvard Medical Area one of most important centers for AIDS research in the world. A group of them has been responsible for pioneering work in the way the virus reproduces itself. Another group has discovered relatives to the AIDS virus.

But connecting these complex medical discoveries to an actual cure is another matter. Harvard researchers hope their work will pave the way to either a vaccine, which would keep people from being infected, or a drug, which would help kill or control the AIDS virus. Their work is also devoted to developing tests to catch people who are carrying the virus and determining how many of them will actually get sick.

However, the road to a cure or preventive treatment for AIDS may well be a long one, Harvard researchers say. "We have a lot of work to do," says Dr. William Haseltine, who directs AIDS research at the Harvard-affiliated Dana-Farber Cancer Institute. "We have to be prepared for the long haul. We should make plans to work on this systematically for 10 to 15 years."

The AIDS virus is called Human T-Lymphotrophic Virus Type III (HTLV-III) in America. And Harvard doctors seek to unravel the genetic and protein makeup of the virus. The work is particularly rewarding because at every turn the researchers seem to discover something which writes a new chapter in biology textbooks.

Haseltine's research focuses on the genetic structure of the AIDS virus. "We analyze the virus' DNA sequence to get a blueprint on what the virus can do," explains Haseltine, who is an associate professor of pathology at the Med School. His lab has found a number of unusual genes on the AIDS virus including the tat-gene which makes it possible for the AIDS virus to replicate many times faster than the average virus, and the art-gene which regulates the virus' speed of reproduction.

Dr. Myron E. Essex directs an effort at the School of Public Health studying the proteins in the virus and the antibodies produced in reaction to the proteins. His group has discovered several viruses related to HTLV-III which may be useful for developing a vaccine.

Vaccine

Harvard researchers spend much of their time trying find ways to apply their discoveries to an AIDS vaccine.

However researchers say that a vaccine may not be viable because of several major problems associated with the HTLV-III virus.

In some cases, people infected with HTLV-III don't develop any immune response at all, and some people who do develop antibodies aren't even protected by them. Since vaccines work by stimulating protective antibodies, there is some question whether a vaccine could work effectively.

"There is a serious question whether human beings make any sort of protective response at all. Nobody can predict whether it will be easy or hard to make a vaccine," Haseltine says.

But Essex, who is a professor of microbiology at the School of Public Health postulates, "It is extremely likely that we'll know within a year whether a vaccine is feasible."

Essex studies the proteins which make up the virus and tries to determine which "structural parts of the virus are biologically significant." From his studies of HTLV-III relatives, "We hope to find a weakened form of the virus. The analogy is to smallpox and cowpox. Cowpox is harmless, but [exposure to it] is protective against smallpox," Essex says.

Earlier this spring, Essex and some researchers in Senegal, Africa, discovered that a large portion of the human population had been infected with a close relative of the AIDS virus. HTLV-IV, as the researchers dubbed the new virus, infects some human white blood cells, just like the AIDS virus, but with one crucial difference--the AIDS virus kills the white blood cells and HTLV-IV does not. Essex says he hopes to "use molecules from HTLV-IV to create a protective response" from the human immune system.