Molecular root of 'exhausted' T cells in chronic viral infection

When you get an acute infection, such as influenza, the body generally responds with a coordinated response of immune-cell proliferation and attack that rapidly clears the pathogen. Then, their mission done, the immune system stands down, leaving a population of sentinel memory cells to rapidly redeploy the immune system in the event of reinfection.But what about chronic infection? In the case of such pathogens as hepatitis C, HIV, and malaria, the body and the pathogen essentially fight to a prolonged stalemate, neither able to gain an advantage. Over time, however, the cells become "exhausted" and the immune system can collapse, giving the pathogen the edge.

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