Purification and biochemical characterization of equine pulmonary surfactant protein D
Hobo, S.; Ogasawara, Y.; Kuroki, Y.; Akino, T.; Yoshihara, T.
American Journal of Veterinary Research 60(3): 368-372
1999
ISSN/ISBN: 0002-9645 PMID: 10188822 Document Number: 510699
Objective-To characterize surfactant protein D (SP-D) isolated from bronchoalveolar lavage fluid (BALF) of healthy horses. Sample Population-BALF from 10 Thoroughbreds (5 males, 5 females; 26 to 40 months old) without history or clinical signs of respiratory tract disease. Procedure-BALF was obtained and centrifuged at 33,000 X g. The supernatant was applied to a mannose-Sepharose 6B affinity column in the presence of calcium, and the bound protein fraction was analyzed by use of sodium dodecyl sulfate-polyacrylamide gel electrophoresis, immunoblot analysis; amino acid composition was determined and partial sequencing was done. Phospholipid binding and liposome aggregation assay were performed, using purified proteins. Results-The protein isolated by use of mannose affinity matrices was SP-D. It bound carbohydrates and phosphatidylinositol, which are the characteristic features of SP-D isolated from other animal species. Amino acid analysis and partial primary sequence of the isolated protein indicated high homology with rat and human SP-D. Furthermore, immunoblot analysis indicated that equine SP-D reacted with human and rat SP-D-specific antibodies. Conclusion and Clinical Relevance-SP-D exists in equine lungs; its measurement may be useful in evaluating equine lung disease.