ANTIBODY AGAINST PULMONARY SURFACTANT PROTEIN-A RECOGNIZES PROTEINS IN INTESTINE AND SWIM BLADDER OF THE FRESH-WATER FISH, CARP

An antibody raised against rat pulmonary surfactant protein A (SP-A) b ound on Western blots to proteins present in intestinal mucosa and in swim bladder, but not in gills of the carp. The fish protein(s) reveal ed by the antibody exhibited an electrophoretical behavior similar to that of rat SP-A with a characteristic triplet in the 30- to 35-kDa ra nge. It therefore appears that proteins immunologically very close to mammalian SP A are present in modern fish which evolved from ancestors that never possessed lungs. The association of SP-A with phospholipid -rich surfactant-like materials appears as a phylogenetically old feat ure. (C) 1996 Academic Press, Inc.