Furthermore, we demonstrate that elastase, a secreted protease that plays a role in several lung diseases [45,46], can cleave SARS-1-S and Rs4081 S protein and allow for trypsin-independent entry of Rs4081 S protein-bearing particles, and that the same is true for the respiratory tract expressed TTSPs TMPRSS11A, TMPRSS11D and TMPRSS11E upon expression in particle producing cells. The gene discussed is PROS1; the disease is lung disorder.