The Independent recently asked the provoking question: Should we end the quest for an HIV vaccine? A vaccine for HIV will certainly be based on a revolutionary idea.
The Problem
One of the major problems with HIV-vaccine research is that CD4+ cells like monocytes and macrophage express an IgG Fc receptor. Thus, any antibody that sticks to HIV is internalized via the FcR into the CD4+ WBC, and thus the WBC are infected by the tagalong HIV. Even antibodies that are "neutralizing" in a Petri dish increase infectivity.
Thus, I was not surprised when the recent Merck HIV vaccine study went terribly, horribly awry, actually increasing the likelihood of infection and leading to earlier death in vaccinated individuals.
No Solution?
Any antibody-stimulating vaccine will have this problem, assuming an IgG response. Passive immunization with F(ab') fragments might meet with a better result.
Should We Stop?
Seth Berkley, president of the International AIDS Vaccine Initiative, said in The Independent's survey: “Most people’s immune systems hold HIV in check for years before they develop AIDS. A small number of HIV-infected people seem never to develop the disease. There are also documented cases of individuals who have been repeatedly exposed to HIV, but have not become infected. If scientists can work out the type of immune responses that protect these individuals, it might provide vital clues about how to create a vaccine.”
The above data that Berkley notes is indeed reason for hope. However, a traditional vaccine will not evoke the anomalous immune responses that are so rarely observed.
TK Kenyon
Author of CALLOUS: A Novel, ( http://www.amazon.com/gp/product/1601640226 ) a story about free will, neuroscience, fate, Schrodinger's Cat, and the End of Days.
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