IgG red blood cell autoantibodies in autoimmune hemolytic anemia bind to epitopes on red blood cell membrane band 3 glycoprotein

Journal Article · Mon Jan 01 04:00:00 EST 1990 · Journal of Laboratory and Clinical Medicine; (USA)

OSTI ID:6937983

Victoria, E J; Pierce, S W; Branks, M J; Masouredis, S P ^[1]

---

1. Univ. of California, San Diego (USA)

Red blood cell (RBC) autoantibodies from patients with IgG warm-type autoimmune hemolytic anemia were labeled with iodine 125 and their RBC binding behavior characterized. Epitope-bearing RBC membrane polypeptides were identified after autoantibody immunoprecipitation of labeled membranes and immunoblotting. Immunoaffinity isolation of labeled membrane proteins with 12 different IgG hemolytic autoantibodies with protein A-agarose revealed a major polypeptide at Mr 95 to 110 kd, which coelectrophoresed on sodium dodecylsulfate-polyacrylamide gel electrophoresis with a membrane component isolated with sheep IgG anti-band 3. Immunoprecipitation studies with chymotrypsinized RBCs resulted in the recovery of two labeled membrane polypeptides with molecular weights characteristically resulting from the chymotryptic fragmentation of band 3. Immunoblotting with sheep IgG anti-band 3 of the immunoprecipitated polypeptides confirmed that hemolytic autoantibody binding led to recovery of band 3 or its fragments. Two 125I-labeled IgG hemolytic autoantibodies showed binding behavior consistent with epitope localization on band 3. The labeled RBC autoantibodies bound immunospecifically to all types of human RBC tested, including those of rare Rh type (Rh-null, D--) at a site density of approximately 10(6) per RBC. The 125I-IgG in two labeled autoantibodies was 84% and 92% adsorbable by human and higher nonhuman primate RBCs. Antigen-negative animal RBC bound less than 10%, consistent with immunospecific RBC binding. IgG-1 was the major subclass in five autoantibodies tested; one of six fixed complement; and autoantibody IgG appeared polyclonal by isoelectric focusing. We conclude that IgG eluted from RBCs of patients with autoimmune hemolytic anemia consists predominantly of a single totally RBC-adsorbable antibody population that binds to antigenic determinants on band 3.

• OSTI ID: 6937983
• Journal Information: Journal of Laboratory and Clinical Medicine; (USA), Journal Name: Journal of Laboratory and Clinical Medicine; (USA) Vol. 115:1; ISSN JLCMA; ISSN 0022-2143
• Country of Publication: United States
• Language: English

Related Subjects

550901* -- Pathology-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANEMIAS
ANIMALS
ANTIBODIES
ANTIGENS
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BLOOD GROUPS
BODY FLUIDS
CELL CONSTITUENTS
CELL MEMBRANES
CHYMOTRYPSIN
COMPLEMENT
DAYS LIVING RADIOISOTOPES
DISEASES
ELECTRON CAPTURE RADIOISOTOPES
ELECTROPHORESIS
ENZYMES
ERYTHROCYTES
GLOBULINS
GLYCOPROTEINS
HEMIC DISEASES
HYDROLASES
IMMUNOGLOBULINS
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
KINETICS
MAMMALS
MAN
MATERIALS
MEMBRANES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PATHOGENESIS
PEPTIDE HYDROLASES
PHENOTYPE
PRIMATES
PROTEINS
RADIOISOTOPES
REACTION KINETICS
SERINE PROTEINASES
SYMPTOMS
VERTEBRATES