There have been major breakthroughs in lung surfactant (LS) research over the
last two decades that have changed our concept of how and why the material
works well at the lung air–water interface. From the initial ideas of a surface
active material lining the alveoli to the seminal concepts of how low surface
tension is reached, the classical ideas about Comroe’s “extraordinary juice”
requires revision and re-thinking.
Collectins are a family of collagenous calcium-dependent
defense lectins in animals. Their polypeptide chains consist
of four regions: a cysteine-rich N-terminal domain,a colla-gen-like region,ana-helical coiled-coil neck domain and
a C-terminal lectin or carbohydrate-recognition domain.
These polypeptide chains form trimers that may assemble
into larger oligomers. The best studied family members are
the mannan-binding lectin,which is secreted into the blood
by the liver,and the surfactant proteins A andD,which are
secreted into the pulmonary alveolar and airway lining fluid....
Encounters with Phagocytes
Phagocytosis and Inflammation Phagocytosis of microbes is a major innate host defense that limits the growth and spread of pathogens. Phagocytes appear rapidly at sites of infection in conjunction with the initiation of inflammation. Ingestion of microbes by both tissue-fixed macrophages and migrating phagocytes probably accounts for the limited ability of most microbial agents to cause disease.