Since the publication of the DRiP (defective ribosomal product) hypothesis in 1996,numerous studies have addressed the contribution of DRiPs to generating viral antigenic peptides for CD8+ T cell immunosurveillance.Here,we review studies characterizing the generation of antigenic peptides from influenza A virus encoded DRiPs,discuss the many remaining mysteries regarding the nature of their co-translational generation,and speculate on where the future might lead.