Human surfactant protein-A contains blood group A antigenic determinants.
A major blood group antigenic epitope was identified on human pulmonary surfactant protein A (SP-A). MAb and polyclonal antibodies generated against purified human SP-A aggregated blood group A human erythrocytes and immunostained epithelial cells in a variety of human tissues, consistent with the tissue distribution of major blood group antigens. SP-A MAb (MAb-8) agglutinated red cells and immunostained tissues from A or AB blood groups, but did not react with cells or tissues from O or B individuals. MAb-8 immunostaining of tissue from blood group A individuals was ablated by incubation with blood group A red cells. MAb and polyclonal antibodies directed against A blood group antigens reacted strongly with purified SP-A obtained from a blood group A individual with alveolar proteinosis. MAb and polyclonal antibodies specific for B blood group antigen failed to react with SP-A from this patient or from patients who were in blood group B. Reactivity of anti-blood group MAb was lost after treatment of SP-A with endoglycosidase-F, demonstrating its reactivity with an epitope dependent on the asparagine-linked oligosaccharide at asparagine 187. Reactivity of MAb-8 with SP-A persisted after endoglycosidase-F treatment, but was lost after digestion with collagenase as assessed by Western blot after SDS-PAGE. Reactivity of MAb to SP-A was sensitive to beta-elimination, supporting the presence of another blood group antigenic site distinct from the epitope dependent on the asparagine-linked carbohydrate. The finding that the SP-A molecule contains a major blood group epitope has implication for the clinical use of surfactant replacement preparations and diagnostic reagents based on this protein.
Stahlman
M T
MT
Department of Pathology and Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-2370.
Gray
M E
ME
Ross
G F
GF
Hull
W M
WM
Wikenheiser
K
K
Dingle
S
S
Zelenski-Low
K R
KR
Whitsett
J A
JA
D000017:ABO Blood-Group System / Q000276:immunology*; D000911:Antibodies, Monoclonal; D000939:Epitopes / Q000276:immunology; D004912:Erythrocytes / Q000276:immunology; D006023:Glycoproteins / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D011510:Proteolipids / Q000276:immunology* / Q000302:isolation & purification / Q000378:metabolism; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000276:immunology* / Q000302:isolation & purification / Q000378:metabolism; D014018:Tissue Distribution
D000017:ABO Blood-Group System; D000911:Antibodies, Monoclonal; D000939:Epitopes; D006023:Glycoproteins; D011510:Proteolipids; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants