[Surfactant proteins A and D: major factors of the immune response of the lung].

Surfactant proteins (SP) A and D play a key role in pulmonary host defense of preterm and term newborns. SP-A and SP-D have structural elements of both collagens and lectins, for which they are called "collectins". SP-A and SP-D coordinate the innate and adaptive immune response in the lung and convey protection against infection in amniotic fluid and vernix caseosa. They are pattern-recognizing molecules of the innate immune system that are involved in binding, agglutination of pathogens, chemotaxis of neutrophils, phagocytosis of pathogens, and production of reactive oxygen species. In addition, SP-A and SP-D interact with the adaptive immune system by reducing interleukin-2 production and T lymphocyte proliferation.