INHBE and infection: This study also depicted an obvious upregulation of transforming growth factor-pseudoreceptor BMP and activin membrane-bound inhibitor with ubiquitous expression on AM and AEC after in vitro infection of COPD lung tissue, indicating that activin membrane-bound inhibitor might play an important role in the early immune response of pulmonary NTHi infection.[27] In a comparative study, this ex vivo tissue culture model was infected with different respiratory pathogens including C. pneumoniae, S. pneumoniae, and H. influenzae.