Member of the TNF ligand family, binds to TNFRSF14 and LTβR on hematopoietic and stromal cells; functions as a costimulatory factor for lymphoid cells and as a deterrent to infection by herpesvirus; stimulates T cell proliferation; triggers tumor cell apoptosis; plays a critical role in NK activation/expansion and activated NK cell and DC priming of CD8+ T cells; increases effector cell priming, recruitment, and retention at tumor sites. Here, CD8A is linked to infection.