Role of T-cell subsets in bacterial infections

Classic functional partitioning of T-cell subsets is being questioned: in many bacterial and protozoan infections, CD8 T cells play a role in protection; two types of CD4 T helper cells have been characterized, one protective, the other exacerbating disease; finally, gamma delta T cells have been implicated in the host response to certain bacteria. Moreover, evidence is accumulating that, in addition to T-cell helper functions, cytolytic T-cell functions participate in antibacterial immunity.