CTSS and Reoviridae infectious disease: For example, CTSB and CTSL cleave viral glycoproteins to facilitate entry of Ebola virus (30, 31); CTSB participates in human papillomavirus type 16 entry (32); CTSL and CTSS support reovirus infection in an acid-independent manner (33, 34); and CTSL mediates spike protein cleavage in coronaviruses, including SARS-CoV, MERS-CoV, and SARS-CoV-2 (35, 36).