T CELLS AND AIDS PROGRESSIONIn another project, AIDS researcher Jay Levy, a professor ofmedicine at the University of California, San Francisco, reportedat the Ninth International AIDS Conference in Berlin that hehas been studying T cells' intercellular messages involved inthe progression of AIDS.

Levy's team identified a CD8 subcategory that he said keepsHIV from multiplying and eliminates other cells infected withHIV. The researchers found a new messenger molecule, aprotein cytokine, that in test tubes stops HIV from replicatingin the CD4 "helper" T cells that the virus infects.

Meanwhile, two distinct populations of CD4 cells each makecytokines that regulate the CD8 cytokine production, Levy'sgroup found. One class of CD4 cells activates the killer T cells,the other classHdominant in late AIDSHinhibits CD8.

This inhibiting class stimulates production of immune B cellsresponsible for antibody production.

However, Levy believes HIV can mutate into forms that arebetter able to infect cells when attached to antibodies. He wasthe first to show that the virus can hitch a ride viamacrophages into the brain.

Levy suggested that therapy might either rely on drugs tointercept the inhibiting message from CD4, provide the CD8anti-HIV factor or increase killer T cells' ability to block HIVreplication. His lab and others are working on the firstapproach, and his team is also exploring the second strategy. --NG061193CD8

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