team developing melanoma vaccine
By Nancy Hurrelbrinck
have discounted for decades the idea that the body's immune system
can fight cancer, but the work of several U.Va. researchers is
proving them wrong.
"Now there's a lot of evidence that immune responses to cancer
do occur," said Craig L. Slingluff Jr., associate professor
of surgery. "We're looking at the response of T-lymphocytes,"
white blood cells that can kill cells infected with a virus, as
well as cancer cells.
"We can take blood from melanoma patients and generate a
population of cells that can kill cells from their tumor,"
said Slingluff, who has been researching melanoma, a form of skin
cancer, with microbiology professor Victor H. Engelhard and Donald
F. Hunt, University Professor of Chemistry and Pathology.
"The big question is how these lymphocytes can exist in the
body and not kill the cancer cells."
answer: tumors can evade immune recognition by making substances
that are immuno-suppressive, he said, adding that he has seen
lymphocytes even in people with advanced disease.
Slingluff's team has been working with Interleukin-2, a growth
factor for lymphocytes that the Food and Drug Administration (FDA)
has approved for treating melanoma for a year.
can generate lymphocytes in a culture that kill tumor cells,"
he said, noting that when patients are given these cells back,
fortified with interleukin-2, their tumors are shrunk as effectively
or better than if they'd used chemotherapy.
problem is that it's a very time-intensive process," he said.
"The patient can die in the time it takes to grow the cells.
We want to treat people in the early stage of the disease, to
stimulate a response in [them] that takes advantage of their immune
Slingluff's team hopes to develop a vaccine reliable enough to
use in healthy people. "We have been trying to identify molecules
on the surface of melanoma that the T-lymphocytes recognize so
we can use those molecules to vaccinate people.'
1991, they've identified four of these molecules and used them
in vaccines that are currently being tested in three clinical
trials, he said.
very exciting to me to be able to offer these treatments. The
standard treatment now is early surgery, then watch and wait,"
he said, adding that, for people with cancer that has spread to
the lymph nodes, who are expected to die within five to 10 years,
there's no treatment with significant impact.
team has set up a human immune therapy center to facilitate establishing
immunology clinical trials. Colleagues are developing a protocol
for a standard immunology therapy vaccine for colon cancer, and
they want to start trials for breast and lung cancer vaccines,
lot of clinicians taking care of patients want to offer new things,"
he said. "The issue is when to translate research into trials
and deal with regulatory agencies" such as the FDA and several
They have gotten the process, which took two years eight years
ago, down to six months.
"We expect that each cancer will eventually have its own
vaccine," he said.