Cystatin D, a natural salivary cysteine protease inhibitor, inhibits coronavirus replication at its physiologic concentration
This study was conducted to examine the effect of cystatin D, a newly discovered salivary cysteine protease inhibitor, on human coronavirus replication. When MRC-5, human diploid lung cells, were incubated with dilutions of recombinant human cystatin D from 0.65-10 microM for 1 h prior to, during and after infection with coronavirus OC43 and 229e strains, a decrease in virus yield was observed res