General-heavy army disastrous in immune battle

Immunologists have identified two big groups of T cells: “helper” CD4+ cells and “killer” CD8+ cells.* The helper cells can produce immune regulatory molecules and promote antibody responses, while the killer cells recognize and destroy virally-infected cells.

A vaccine against a virus that stimulates only helper CD4+ cells leads to uncontrolled lethal inflammation in mice once the animals are challenged with the virus, a recent paper in Science shows. Emory Vaccine Center director Rafi Ahmed is a co-author.

Senior author Dan Barouch, from Harvard/Beth Israel Deaconess Medical Center, tells The Scientist that CD4+ cells are like generals directing the battle of the immune system and “if you just have strategic generals and no soldiers, it turns out to be worse than having no army at all.” Rebalancing the system with antiviral CD8+ T cells or antibodies helps limit the problems.

The findings mesh with work by Yerkes investigators [Guido Silvestri and colleagues] suggesting that HIV vaccines that boost CD4+ cells in gateway mucosal tissues lead to higher rates of infection. In both cases, the lesson is: having more helper CD4+ T cells around actually does not help.

*Yes, I’m oversimplifying. There are other kinds of T cells, such as gamma delta T cells and regulatory T cells.


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Posted on by Quinn Eastman in Immunology Leave a comment

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Quinn Eastman

Science Writer, Research Communications 404-727-7829 Office

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