Gottlieb and Friedman-Kien began capturing attention, what sort of pathogen caused this combination of puzzling, lethal symptoms—nor even if there was a single pathogen. The virus idea arose as a plausible guess.
One scientist who made the guess was Luc Montagnier, then a little-known molecular biologist at the Institut Pasteur in Paris. Montagnier’s research had focused mainly on cancer-causing viruses, especially the group known as retroviruses, some of which cause tumors in birds and mammals. Retroviruses are fiendish beasts, even more devious and persistent than the average virus. They take their name from the capacity to move backward (retro) against the usual expectations of how a creature translates its genes into working proteins. Instead of using RNA as a template for translating DNA into proteins, the retrovirus converts its RNA into DNA within a host cell; its viral DNA then penetrates the cell nucleus and gets itself integrated into the genome of the host cell, thereby guaranteeing replication of the virus whenever the host cell reproduces itself. Luc Montagnier had studied these things in animals—chickens, mice, primates—and wondered about the possibility of finding them in human tumors too. Another disquieting possibility about retroviruses was that the new disease showing up in America and Europe, AIDS, might be caused by one.
There was still no solid proof that AIDS was caused by a virus at all. But three kinds of evidence pointed that way, and Montagnier recalls them in his memoir, a book titled Virus. First, the incidence of AIDS among homosexuals linked by sexual interactions suggested that it was an infectious disease. Second, the incidence among intravenous drug users suggested a blood-borne infectious agent. Third, the cases among hemophiliacs implied a blood-borne agent that escaped detection in processed blood products such as clotting factor. So: It was infinitesimal, contagious, blood-borne. “AIDS could not be caused by a conventional bacterium, a fungus, or protozoan,” Montagnier wrote, “since these kinds of germs are blocked by the filters through which the blood products necessary to the survival of hemophiliacs are passed. That left only a smaller organism: the agent responsible for AIDS thus could only be a virus.”
Other evidence hinted that it might be a retrovirus. This was new ground, but then so was AIDS. The only known human retrovirus as of early 1981 was something called human T-cell leukemia virus (HTLV), recently discovered under the leadership of a smart, outgoing, highly regarded, and highly ambitious researcher named Robert Gallo, whose Laboratory of Tumor Cell Biology was part of the National Cancer Institute in Bethesda, Maryland. HTLV, as its name implies, attacks T cells and can turn them cancerous. T cells are one of the three major types of lymphocyte of the immune system. (Later the acronym HTLV was recast to mean human T-lymphotropic virus, which is slightly more accurate.) A related retrovirus, feline leukemia virus, causes immune deficiency in cats. So a suspicion arose among cancer-virus researchers that the AIDS agent, destroying human immune systems by attacking their lymphocytes (in particular, a subcategory of T cells known as T-helper cells), might likewise be a retrovirus. Montagnier’s group began looking for it.
Gallo’s lab did too. And those two weren’t alone. Other scientists at other laboratories around the world recognized that finding the cause of AIDS was the hottest, the most urgent, and potentially the most rewarding quest in medical research. By late spring of 1983, three teams working independently had each isolated a candidate virus, and in the May 20 issue of Science, two of those teams published announcements. Montagnier’s group in Paris, screening cells from a thirty-three-year-old homosexual man who’d been suffering from lymphadenopathy (swollen lymph nodes), had found a new retrovirus, which they called LAV (for lymphadenopathy virus). Gallo’s group came up with a new virus also, one that Gallo took for a close relative of the human T-cell leukemia viruses (by now there was a second, called HTLV-II, and the first had become HTLV-I) that he and his people had discovered. He called this newest bug HTLV-III, nesting it proprietarily into his menagerie. The French LAV and the Gallo HTLVs had at least one thing in common: They were indeed retroviruses. But within that family exists some rich and important diversity. An editorial in the same issue of Science trumpeted the Gallo and Montagnier papers with a misleading headline: HUMAN T-CELL LEUKEMIA VIRUS LINKED TO AIDS, despite the fact that Montagnier’s LAV was not a human T-cell leukemia virus. Woops, mistaken identity. Montagnier knew better, but his Science paper seemed to blur