Monoclonal antibodies that recognize different membrane proteins that are deficient in Rhnull human erythrocytes. One group of antibodies reacts with a variety of cells and tissues whereas the other group is erythroid-specific

Abstract

1. Rhnull human erythrocytes lack all of the antigens of the Rh and LW blood group systems and have abnormal shape and an increased osmotic fragility. In this paper two murine monoclonal antibodies raised against intact human erythrocytes were used to investigate further the abnormalities in these cells. BRIC 125 reacts weakly with Rhnull erythrocytes and BRIC 69 does not react at all. The results showed that BRIC 125 reacts with a component of Mr 47,000-52,000 which has a substantial content of N-glycans. In contrast, BRIC 69 reacted with a band of Mr 31,000 together with a very diffuse band of Mr 35,000-52,000. Treatment of BRIC 69 immunoprecipitates with endoglycosidase F/peptidyl-N-glycosidase F resulted in the loss of both BRIC 69 reactive components and the appearance of a new band of Mr similar to that of the Rh(D) polypeptide. 2. BRIC 125 had a broad reactivity with cells in peripheral blood, whereas the reactivity of BRIC 69 was confined to erythrocytes. BRIC 125, but not BRIC 69, reacted with human kidney tissue and bound to endothelium in peritubular capillaries, arteries and veins as well as the epithelial tissue of distal tubules. BRIC 125 stained haemopoietic cells, foetal hepatocytes and megakaryocytes in foetal liver and sinusoidal cells, hepatocytes and portal tracts in adult liver. In contrast, BRIC 69 reactivity was confined to haemopoietic cells in foetal liver. The BRIC 125 epitope has a wide tissue distribution, suggesting the occurrence of a related group of polypeptides which have a general functional role on cell surfaces. 3. Rhnull erythrocytes are deficient in at least four different membrane polypeptides.

4.1R-deficient human red blood cells have altered phosphatidylserine exposure pathways and are deficient in CD44 and CD47 glycoproteins

“…15,17 CD47 was reduced in Rhnull patients. 16 In patient A, CD47 was reduced at the expense of its high molecular weight isoforms, and was almost completely missing in patient B. There are at least five different isoforms of CD47 known to exist in humans, and the pattern found in patient A may be consistent with 4.1R interacting specifically with CD47 isoforms with longer C-terminal domains.…”

“…14,15 It is much reduced in regulator type Rhnull patients. 16 It is also secondarily reduced in hereditary spherocytosis associated with missing protein 4.2 15,17 or band 3.…”

PrPSc Binding Antibodies Are Potent Inhibitors of Prion Replication in Cell Lines

“…A triplicate of ScRov cells was treated with the ICSM mAbs once a week just after splitting. The controls were either left untreated or treated with isotype control mAb (15,16). In one experiment, the cells were exposed to similar concentrations of dextran sulfate 500 (DS500, Sigma).…”

“…Lysates then were incubated with 10 g/ml purified mAbs in lysis buffer for 2 h at 4°C on a rotator. Negative controls omitted the capture mAb or used the relevant isotype control (15,16). The immune complexes were adsorbed overnight onto protein G-agarose beads (Roche Applied Science) at 4°C on a rotator.…”

The Lutheran blood group glycoprotein, another member of the immunoglobulin superfamily, is widely expressed in human tissues and is developmentally regulated in human liver.

“…IgSF members are found in the membrane of the mature human erythrocyte. The ubiquitous cell-surface glycoprotein CD47 was first identified on erythrocytes by using monoclonal antibodies (2). CD47 contains an immunoglobulin domain and is identical to the ovarian carcinoma marker OA3 and the integrin-associated protein IAP (3,4).…”