Surfactant protein D is a member of the collectin family of innate immune modulators. It is constitutively secreted by alveolar lining cells and epithelium associated with tubular structures, that contains a N-terminal collagen-like domain and a C-terminal lectin domain that are characteristic of members of the collectin family of proteins, and also shows calcium-dependent binding to specific saccharides. Besides it is involved in the development of acute and chronic inflammation of the lung. Several human lung diseases are characterized by decreased levels of bronchoalveolar SP-D.
Recombinant Human SP-D produced in HEK 293 cells is a polypeptide chain containing 355 amino acids. A fully biologically active molecule, rhSP-D has a molecular mass of 40-45 kDa analyzed by reducing SDS-PAGE and is obtained by chromatographic techniques at GenScript.