Department of Pathology and Infectious Diseases, The Royal Veterinary College, University of London, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire, AL9 7TA, UK. E-mail: bpsingh@rvc.ac.uk.
The collectins are a group of multimeric proteins in which the individual chains consist of a C-type lectin domain attached to a collagen domain via an alpha-coiled neck region. The chains are organized into a triple collagen helix and oligomerized through N-terminally located cysteines. The collectins perform dual function: these molecules can bind to sugar residues on the surface of a pathogen via the peripheral lectin domain; and subsequently interact through its collagen domain with phagocytes and/or the complement system to destroy the pathogen. In the lung two members of collectin family surfactant proteins SP-A and SP-D are major the constituents. Pulmonary collectins are involved in lung innate immune defense. Lack or low levels of the collectins may cause increase susceptibility to infections especially during the neonatal period between the maternally acquired immunity and a fully developed adaptive immunity and also in the state of impaired immune functions. The present paper deals with the structure and functional significance of pulmonary collectins SP-A and SP-D molecules in lung innate immunity.
Collectins, Lungs, Innate immunity
