Removing the Worst Aspect of Chronic Infection
An important aspect of immune system aging is the lack of naive T cells resulting from long periods of chronic infection by viruses like cytomegalovirus. What if we could reconfigure the immune system to behave more rationally when presented with recurring threats, and thus not exhaust its resources? That might be a possibility: "preventing white blood cells' circulation by trapping them in the lymph nodes can help mice get rid of a chronic viral infection ... laboratory mice can fight off infection by the Armstrong strain of lymphocytic choriomeningitis virus (LCMV), but are vulnerable to chronic infection by a variant called clone 13. ... infecting mice with the Armstrong strain sequesters white blood cells in the lymph nodes, while clone 13 does so less stringently. ... Our hypothesis was that if we could artificially induce conditions like those produced by the Armstrong strain, it would help the immune system clear an infection by clone 13 ... an experimental drug called FTY720 [prevents] white blood cells from leaving lymph nodes ... Even if mice have a stable chronic LCMV clone 13 infection, treatment with FTY720 can still improve their immune response against LCMV enough to have them rid it from their systems ... FTY720 appears to prevent 'exhaustion' in the group of white blood cells called CD8+ T cells."
Link: http://www.eurekalert.org/pub_releases/2008-08/eu-twb_1080808.php