Wednesday, March 07, 2007

An innovative HIV vaccination scheme

I'm currently in Denver looking for Physics of Sex topics at the year's largest gathering of physicists, the American Physical Society's annual March meeting.

Yesterday I saw a presentation by physicist Michael Deem of Rice University. He applies the math of physics (including things like field theory) to look at all kinds of things in biology and medicine.

One of the papers he presented at the conference analyzed the ways that HIV manages to evade the immune response. His research suggests an intriguing vaccination technique that could cope with the ability of HIV to rapidly evolve in the human body.

One of the problems with viruses like HIV is that it mutates after infection and produces of several different virus strains. Your body's immune system develops T-cells to fight each of the strains, but tends to focus on just one variety. That means you are pretty good at fending off only one strain, while the rest of the strains run amock.

Deem's analysis of HIV suggests that once vaccines against the disease are developed, similar problems would arise if we tried to vaccinate against more than one strain at a time with a single shot containing a blend of vaccines - that is, only one of the vaccine varieties would take effect.

In order to counteract the problem, Deem proposes that future HIV vaccines should be given with several shots simultaneously injected at different locations around the body. The reason is that T-cells are produced in the lymph nodes located primarily near your joints (behind your jaw, under your armpits, etc.). Introducing different vaccines near different joints induces lymph nodes at one location to concentrate on fighting one particular viral strain, while leaving other strains to other lymph nodes.

When HIV vaccines are finally developed, a person at risk might get a shot in each shoulder, one near each hip, and maybe even at the knees or elbows.

In the meantime, Deem thinks the scheme could help in the prevention of dengue fever. Apparently there are vaccines for several strains of dengue fever, but getting the shot for one strain prevents the others from taking effect, and can increase the risk of developing life-threatening dengue hemorrhagic fever. Deem is hoping to get some medical studies started to see of his multi-shot vaccination scheme works against dengue fever, and eventually against HIV.

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