Researchers
are looking at ways to re-invigorate "exhausted" CD8 T cells.
They says the cells eventually become "exhausted"
in their battle against persistent viral infection and less effective in
fighting the disease.
In a study to be published Dec. 28 on the
journal Nature's Web site, researchers at Dana-Farber Cancer Institute
and Emory University have traced the problem to a gene that turns off the
infection-fighting drive of CD8 T cells in mice.
Researchers said the discovery raises the
possibility that CD8 cell exhaustion can be reversed in human patients,
reinvigorating the immune system's defenses against chronic viral infections
ranging from hepatitis to HIV.
In mouse studies, CD8 T cells were reinvigorated
by PD-1/PD-L1 blockers.
If human CD8 T cells are found to operate
by a similar mechanism, the new findings may offer a simple immunological
strategy for treating chronic viral infections, researchers said.
Freeman's lab is also exploring whether anti-cancer
T cells become exhausted in various types of tumors and in HIV-infected
individuals.
Freeman and his collaborators have recently
received a grant from the Bill and Melinda Gates Foundation's Grand Challenges
in Global Health program to extend their findings to hepatitis C infection.
