Blockade of the PD-1 pathway using anti-PD-L1 or anti-PD-1 antibodies during the early phase of acute LCMV infection increased mTOR signaling and granzyme B expression in virus-specific CD8 T cells and resulted in faster clearance of the infection.
Surprisingly, they also show that chronic HIV and lymphocytic choriomeningitis virus infections have a very different impact on fundamental T-cell functions, "exhausted" lymphocytic choriomeningitis virus-specific cells losing the capacity to secrete IFN-γ but maintaining some cytotoxic activity as granzyme B and FasL are overexpressed and, while down-regulating T-bet, up-regulating Eomesodermin expression.
In mouse models, both elevated expression of Spi6 and the complete absence of granzyme B in CD8+ T cells led to an increase in memory cells after infection with lymphocytic choriomeningitis virus.