快猫短视频

COMBINING two approaches to an AIDS vaccine could provide a powerful weapon
against the disease, tests on monkeys suggest.

Many experts believe that effective immunisation against HIV requires the
body to produce killer T cells, which destroy infected cells. This process
starts when special cells display viral fragments, or antigens, to the immune
system. Doing this with DNA vaccines has had some success but often doesn鈥檛
produce a strong enough immune response.

Another strategy is to infect dendritic cells鈥攖he body鈥檚 most potent
antigen-presenting cells鈥攚ith a weakened form of the virus. Again,
researchers have had some success in animal tests but manipulating the AIDS
virus is tricky.

So Julianna Lisziewicz of the Research Institute for Genetic and Human
Therapy in Washington DC decided to combine the two approaches by creating a
piece of DNA containing most of HIV鈥檚 genes, but not enough to form viral
particles. Her team sneaked this DNA into the dendritic cells of pigtail macaque
monkeys.

Both animals injected with the DNA-treated cells showed vigorous production
of anti-HIV killer T cells that could still be detected seven months later. But
there was no antibody production, so the immune response was highly
specific.

鈥淚 find it very exciting that we can get such a pure response,鈥� says
Lisziewicz. Some rare patients who survive HIV infection without therapy have
exactly this response, she says.

But Raul Andino of the University of California, San Francisco, says it鈥檚
unclear whether a focused or a broader immune response including antibodies is
best. 鈥淲e鈥檒l only learn that in human trials.鈥�