Table 3.

Several functions of pulmonary surfactants in asthma

Surfactant	Function		Target
SP-A/SP-D	Host defense	Binding to pathogen	Virus, bacteria, and fungi
		Induction of phagocytosis	Pathogens and apoptotic cells
	Immune regulation	Suppression of cell maturation (SP-A)	Dendritic cells
		Enhancement of antigen presentation (SP-D)	Dendritic cells
		Reduction of cell activation/proliferation	Lymphocytes (T cells)
		Modulation of cell migration/recruitment	Monocytes and neutrophils
		Inhibition of extracellular trap formation (SP-D)	Eosinophils
SP-B/SP-C	Surface film formation	Reduction of surface tension	Air–liquid interface