PRF1 and influenza: Using a model of A549 cells, human lung alveolar epithelial cells, infected by human (H1N1) influenza virus, it was found that aminobisphosphonate pamidronate (PAM)-expanded Vγ9Vδ2 T cells from PBMC of healthy donors were efficiently able to control influenza pathogenesis by non-cytolytic inhibition of influenza replication and by direct killing of influenza-infected cells through cytolytic pathways of perforin/granzyme B, TRAIL, and Fas-FasL in a NKG2D-mediated cell to cell contact-dependent manner [9].