SAN FRANCISCO-Protection by self-immunization may help explain why some people repel HIV despite intense exposure.
The protective process, mediated by CD8 cells, involves a CD8-cell antiviral factor that may be an important response HIV vaccines should elicit, says UCSF’s Dr. Jay Levy.
Of the 87 people his group is following, who all remain virus-free even after multiple exposures to HIV, only two lack the CCR-5 co-receptor molecule that allows viral entry into the lymphocytes, Dr. Levy told a forum at UCSF’s new AIDS Research Institute. But 43 seem protected by the CD8 antiviral response.
In vitro studies found viral replication was stopped when CD4 cells were incubated with CD8 cells, but virus grew in the target cells when CD8 lymphocytes were removed.
Dr. Levy believes the response is triggered by an initial exposure to low amounts of HIV, and that each subsequent exposure acts like a booster vaccine.
