Gallo, Robert C. WORLD OF MICROBIOLOGY AND IMMUNOLOGY234•
sibility that certain kinds of cancer had viral origins, and he set
up his new laboratory to study human retroviruses.
Retroviruses are types of viruses that possess the ability to
penetrate other cells and splice their own genetic material into
the genes of their hosts, eventually taking over all of their
reproductive functions. At the time Gallo began his work,
retroviruses had been found in animals; the question was
whether they existed in humans. His research involved efforts
to isolate a virus from victims of certain kinds of leukemia,
and he and his colleagues were able to view a retrovirus
through electron microscopes. In 1975, Gallo and Robert E.
Gallagher announced that they had discovered a human
leukemia virus, but other laboratories were unable to replicate
their results. Scientists to whom they had sent samples for
independent confirmation had found two different retroviruses
not from humans, but from animals. The samples had been
contaminated by virusesfrom a monkey or a chimp.
Despite the setback, Gallo continued his efforts to iso-
late a human retrovirus. He turned his attention to T-cells,
white blood cells which are an important part of the body’s
immune system, and developed a substance called T-cell
growth factor (later called interleukin–2), which would sustain
them outside the human body. The importance of this growth
factor was that it enabled Gallo and his team to sustain can-
cerous T-cells long enough to discover whether a retrovirus
existed within them. These techniques allowed Gallo and his
team to isolate a previously unknown virus from a leukemia
patient. He named the virus human T-cell leukemia virus, or
HTLV, and he published this finding in Sciencein 1981. This
time his findings were confirmed.
It was Gallo’s experience with viral research that made
him important in the effort to identify the cause of AIDS, after
that disease had first been characterized by doctors in the
United States. In further studies of HTLV, Gallo had estab-
lished that it could be transmitted by breast-feeding, sexual
intercourse, and blood transfusions. He also observed that the
incidence of cancers caused by this virus was concentrated in
Africa and the Caribbean. HTLV had these and other charac-
teristics in common with what was then known about AIDS,
and Gallo was one of the first scientists to hypothesize that the
disease was caused by a virus. In 1982, the National Cancer
Institute formed an AIDS task force with Gallo as its head. In
this capacity he made available to the scientific community
the research methods he had developed for HTLV, and among
those whom he provided with some early technical assistance
was Luc Montagnier at the Pasteur Institute in Paris.
Gallo tried throughout 1983 to get the AIDS virus to
grow in culture, using the same growth factor that had worked
in growing HTLV, but he was not successful. Finally, a mem-
ber of Gallo’s group named Mikulas Popovic developed a
method to grow the virus in a line of T-cells. The method con-
sisted, in effect, of mixing samples from various patients into
a kind of a cocktail, using perhaps ten different strains of the
virus at a time, so there was a higher chance that one would
survive. This innovation allowed the virus to be studied, and
observing the similarities to the retroviruses he had previously
discovered, Gallo called it HTLV–3. In 1984, he and his col-
leagues published their findings in Science.Gallo and theother scientists in his laboratory were able to establish that this
virus caused AIDS, and they developed a blood test for the
virus.
Almost a year before Gallo announced his findings,
Montagnier at the Pasteur Institute had identified a virus he
called LAV, though he was not able to prove that it caused
AIDS. The two laboratories were cooperating with each other
in the race to find the cause of AIDS and several samples of this
virus had been sent to Gallo at the National Cancer Institute.
The controversy which would embroil the American scientist’s
career for almost the next decade began when the United States
government denied the French scientists a patent for the AIDS
test and awarded one to his team instead. The Pasteur Institute
believed their contribution was not recognized in this decision,
and they challenged it in court. Gallo did not deny that they had
preceded him in isolating the virus, but he argued that it was
proof of the causal relationship and the development of the
blood test which were most important, and he maintained that
these advances had been accomplished using a virus which had
been independently isolated in his laboratory.
This first stage of the controversy ended in a legal set-
tlement that was highly unusual for the scientific community:
Gallo and Montagnier agreed out of court to share equal credit
for their discovery. This settlement followed a review of
records from Gallo’s laboratory and rested on the assumption
that the virus Gallo had discovered was different from the one
Montagnier had sent him. An international committee
renamed the virus HIV, and in what Specter calls “the first
such negotiated history of a scientific enterprise ever pub-
lished,” the American and French groups published an agree-
ment about their contributions in Naturein 1987. In 1988,
Gallo and Montagnier jointly related the story of the discover-
ies in Scientific American.
Questions about the isolation of the AIDS virus were
revived in 1989 by a long article in the Chicago Tribune. The
journalist, a Pulitzer Prize winner named John Crewdson, had
spent three years investigating Gallo’s laboratory, making over
one hundred requests under the Freedom of Information Act.
He directly questioned Gallo’s integrity and implied he had
stolen Montagnier’s virus. The controversy intensified when it
was established that the LAV virus which the French had iso-
lated and the HTLV–3 virus were virtually identical. The
genetic sequencing in the two were in fact so close that some
believed they actually came from the same AIDS patient, and
Gallo was accused of simply renaming the virus Montagnier
had sent him. Gallo’s claim to have independently isolated the
virus was further damaged when it was discovered that in the
1984 Sciencearticle announcing his discovery of HTLV–3 he
had accidently published a photograph of Montagnier’s virus.
In 1990, pressure from a congressional committee
forced the NIH to undertake an investigation. The NIH inves-
tigation found Popovic guilty of scientific misconduct but
Gallo guilty only of misjudgment. A committee of scientists
that oversaw the investigation was strongly critical of these
conclusions, and the group expressed concern that Popovic
had been assigned more than a fair share of the blame. In June
1992, the NIH investigation was superseded by the Office of
Research Integrity (ORI) at the Department of Health andwomi_G 5/6/03 3:18 PM Page 234