Immunospecific red cell binding of iodine /sup 125/-labeled immunoglobulin G erythrocyte autoantibodies
The primary interaction of autoantibodies with red cells has been studied by using labeled autoantibodies. Immunoglobulin G red cell autoantibodies obtained from IgG antiglobulin-positive normal blood donors were labeled with radioactive iodine and compared with alloanti-D with respect to their properties and binding behavior. Iodine /sup 125/-labeled IgG autoantibody migrated as a single homogeneous peak with the same relative mobility as human IgG on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The isoelectric focusing pattern of labeled autoantibodies varied from donor to donor but was similar to that of alloanti-D, consisting of multiple IgG populations with isoelectric points in the neutral to alkaline range. /sup 125/I-autoantibody bound to all human red cells of common Rh phenotypes. Evidence for immunospecific antibody binding of the labeled autoantibody was based on variation in equilibrium binding to nonhuman and human red cells of common and rare phenotypes, enhanced binding after red cell protease modification, antiglobulin reactivity of cell-bound IgG comparable to that of cell-bound anti-D, and saturation binding in autoantibody excess. Scatchard analysis of two /sup 125/I-autoantibody preparations yielded site numbers of 41,500 and 53,300 with equilibrium constants of 3.7 and 2.1 X 10(8) L X mol-1. Dog, rabbit, rhesus monkey, and baboon red cells were antigen(s) negative by quantitative adsorption studies adsorbing less than 3% of the labeled autoantibody. Reduced ability of rare human D--red blood cells to adsorb the autoantibody and identification of donor autoantibodies that bind to Rh null red blood cells indicated that eluates contained multiple antibody populations of complex specificities in contrast to anti-D, which consists of a monospecific antibody population. Another difference is that less than 70% of the autoantibody IgG was adsorbed by maximum binding red blood cells as compared with greater than 85% for alloanti-D.
- Research Organization:
- Univ. of California San Diego, La Jolla
- OSTI ID:
- 6180832
- Journal Information:
- J. Lab. Clin. Med.; (United States), Vol. 110:3
- Country of Publication:
- United States
- Language:
- English
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SPECIFICITY
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BLOOD GROUPS
DOGS
ELECTROPHORESIS
ERYTHROCYTES
IODINE 125
MAN
MONKEYS
RABBITS
TRACER TECHNIQUES
ANIMALS
BETA DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BLOOD
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ELECTRON CAPTURE RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
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NUCLEI
ODD-EVEN NUCLEI
PRIMATES
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550201* - Biochemistry- Tracer Techniques