scholarly journals REACTIVE LYSIS: THE COMPLEMENT-MEDIATED LYSIS OF UNSENSITIZED CELLS

1970 ◽  
Vol 131 (4) ◽  
pp. 643-657 ◽  
Author(s):  
P. J. Lachmann ◽  
R. A. Thompson
Keyword(s):  
Binding Site ◽  
Complement Activation ◽  
Stable Complex ◽  
Red Cell ◽  
Complement Components ◽  
Heat Stable ◽  
Human Sera ◽  
Red Cell Membranes ◽  
Short Time ◽  
Do So

It has been shown that the "activated reactor" that is produced in certain human sera by complement activation is a stable complex of the fifth and sixth component of complement (C56). On interaction with C7, the indicator factor, a complex C567 is formed which for a short time (half-life less than 1 min) has an activated binding site and can attach itself to normal red cell membranes, conferring on them the hemolytic properties of the "heat stable" complement intermediate EC 1 ∼ 7, the capacity to be lysed by C8 and C9. These cells have neither antibody nor the complement components up to C3 bound on them. The binding site—activated C567c—can similarly bind to other hydrophobic surfaces, including agarose gel where it forms a "stainable line". If the complex is not bound to a surface, the binding site decays and the resulting complex will no longer give rise to lysis. However it will still inactivate C8 and C9 in solution. The sera that can generate activated reactor apparently do so because they have an excess of C5 and C6, compared to their content of C7. The phenomenon of reactive lysis thus represents complement-mediated lysis of unsensitized cells initiated at the C5 stage by a stable complex (C56) which was generated by complement activation at a distance. The immunochemistry of the phenomenon is described and some of its implications discussed.

scholarly journals Effect of RBCs on the activation of human complement by heparin- protamine complexes

Blood ◽  
1988 ◽  
Vol 71 (1) ◽  
pp. 36-40 ◽  
Author(s):  
KA Shastri ◽  
MJ Phillips ◽  
S Raza ◽  
GL Logue ◽  
PK Rustagi
Keyword(s):  
Monoclonal Antibody ◽  
Human Serum ◽  
Complement Activation ◽  
Cell Concentration ◽  
Fluid Phase ◽  
Red Cells ◽  
Red Cell ◽  
Human Complement ◽  
Red Cell Membranes ◽  
Classic Pathway

Abstract Complement activation on red cells by heparin-protamine complexes was studied by using whole human serum. C3 bound to red cells was measured by radiolabeled monoclonal antibody to C3, and fluid-phase C5a was determined by radioimmunoassay. Heparin and protamine in clinically relevant concentrations caused the binding of C3 to red cell membranes, and the measurement of C3 binding provided a sensitive indicator of complement activation produced by these complexes. Complement activation by these reagents occurred at concentration ratios of protamine and heparin at which protamine neutralized the anticoagulant effect of heparin. Heparin-protamine complexes appeared to bind to red cells and produce complement activation by the classic pathway. C5a generation with heparin-protamine complexes in serum was greatly enhanced in the presence of red cells and increased with increasing red cell concentration. This enhancement of complement activation in the presence of red cells was also seen as measured by depletion of available C3 hemolytic complement units in the fluid phase. Thus red cells seem to play an important role in activation of complement by heparin-protamine complexes.

scholarly journals Effect of RBCs on the activation of human complement by heparin- protamine complexes

Blood ◽  
1988 ◽  
Vol 71 (1) ◽  
pp. 36-40
Author(s):  
KA Shastri ◽  
MJ Phillips ◽  
S Raza ◽  
GL Logue ◽  
PK Rustagi
Keyword(s):  
Monoclonal Antibody ◽  
Human Serum ◽  
Complement Activation ◽  
Cell Concentration ◽  
Fluid Phase ◽  
Red Cells ◽  
Red Cell ◽  
Human Complement ◽  
Red Cell Membranes ◽  
Classic Pathway

Complement activation on red cells by heparin-protamine complexes was studied by using whole human serum. C3 bound to red cells was measured by radiolabeled monoclonal antibody to C3, and fluid-phase C5a was determined by radioimmunoassay. Heparin and protamine in clinically relevant concentrations caused the binding of C3 to red cell membranes, and the measurement of C3 binding provided a sensitive indicator of complement activation produced by these complexes. Complement activation by these reagents occurred at concentration ratios of protamine and heparin at which protamine neutralized the anticoagulant effect of heparin. Heparin-protamine complexes appeared to bind to red cells and produce complement activation by the classic pathway. C5a generation with heparin-protamine complexes in serum was greatly enhanced in the presence of red cells and increased with increasing red cell concentration. This enhancement of complement activation in the presence of red cells was also seen as measured by depletion of available C3 hemolytic complement units in the fluid phase. Thus red cells seem to play an important role in activation of complement by heparin-protamine complexes.

BRIEF REPORT: Freeze-Cleaving of Red Cell Membranes in Paroxysmal Nocturnal Hemoglobinuria

Blood ◽  
1967 ◽  
Vol 30 (6) ◽  
pp. 785-791 ◽  
Author(s):  
RONALD S. WEINSTEIN ◽  
ROGER A. WILLIAMS
Keyword(s):  
Paroxysmal Nocturnal Hemoglobinuria ◽  
Cell Membranes ◽  
Red Cells ◽  
Red Cell ◽  
Electron Microscopic ◽  
Structural Differences ◽  
Microscopic Studies ◽  
Red Cell Membranes

Abstract Electron microscopic studies on dried isolated red cell ghosts have been reported to show lesions associated with cell membranes in paroxysmal nocturnal hemoglobinuria (PNH). In this study, carbon-platinum replicas of membranes of freeze-cleaved, partially hydrated PNH red cells and isolated PNH cell ghosts failed to confirm the existence of these abnormalities. This suggests that the previously described lesions are the products of drying artifacts, although they may reflect hidden structural differences between PNH and normal red cell membranes.

scholarly journals Temperature effects on sodium pump phosphoenzyme distribution in human red blood cells.

1985 ◽  
Vol 85 (1) ◽  
pp. 123-136 ◽  
Author(s):  
J H Kaplan ◽  
L J Kenney
Keyword(s):  
Atpase Activity ◽  
Cell Membranes ◽  
Conformational Transition ◽  
Fold Increase ◽  
Inhibitory Effect ◽  
Red Cell ◽  
Na Pump ◽  
Na Ions ◽  
Red Cell Membranes ◽  
Increasing Temperature

Phosphorylation of red cell membranes at ambient temperatures with micromolar [32P]ATP in the presence of Na ions produced phosphoenzyme that was dephosphorylated rapidly upon the addition of ADP or K ions. However, as first observed by Blostein (1968, J. Biol. Chem., 243:1957), the phosphoenzyme formed at 0 degrees C under otherwise identical conditions was insensitive to the addition of K ions but was dephosphorylated rapidly by ADP. This suggested that the conformational transition from ADP-sensitive, K-insensitive Na pump phosphoenzyme (E1 approximately P) to K-sensitive, ADP-insensitive phosphoenzyme (E2P) is blocked at 0 degrees C. Since the ATP:ADP exchange reaction is a partial reaction of the overall enzyme cycle dependent upon the steady state level of E1 approximately P that is regulated by [Na], we examined the effects of temperature on the curve relating [Na] to ouabain-sensitive ATP:ADP exchange. The characteristic triphasic curve seen at higher temperatures when [Na] was between 0.5 and 100 mM was not obtained at 0 degrees C. Simple saturation was observed instead with a K0.5 for Na of approximately 1 mM. The effect of increasing temperature on the ATP:ADP exchange at fixed (150 mM) Na was compared with the effect of increasing temperature on (Na + K)-ATPase activity of the same membrane preparation. It was observed that (a) at 0 degrees C, there was significant ouabain-sensitive ATP:ADP exchange activity, (b) at 0 degrees C, ouabain-sensitive (Na + K)-ATPase activity was virtually absent, and (c) in the temperature range 5-37 degrees C, there was an approximately 300-fold increase in (Na + K)-ATPase activity with only a 9-fold increase in the ATP:ADP exchange. These observations are in keeping with the suggestion that the E1 approximately P----E2P transition of the Na pump in human red cell membranes is blocked at 0 degrees C. Previous work has shown that the inhibitory effect of Na ions and the low-affinity stimulation by Na of the rate of ATP:ADP exchange occur at the extracellular surface of the Na pump. The absence of both of these effects at 0 degrees C, where E1 approximately P is maximal, supports the idea that external Na acts through sites on the E2P form of the phosphoenzyme.

scholarly journals FAMILIAL ACCRECATION OF SODIUM TRANSPORT SYSTEMS (STS) IN RED CELL MEMBRANES AND ESSENTIAL HYPERTENSIVE (EH) PATIENTS WITH THEIR OFFSPRINGS

1987 ◽  
Vol 22 (3) ◽  
pp. 369-369
Author(s):  
R Simsolo ◽  
M Gimenez ◽  
B Grunfold ◽  
A Furci ◽  
L Da Graccn ◽  
...  
Keyword(s):  
Sodium Transport ◽  
Cell Membranes ◽  
Transport Systems ◽  
Red Cell ◽  
Red Cell Membranes

Fine structure of the band 3 protein in human red cell membranes: Freeze-fracture studies

1978 ◽  
Vol 8 (3) ◽  
pp. 325-335 ◽  
Author(s):  
Ronald S. Weinstein ◽  
Jena K. Khodadad ◽  
Theodore L. Steck
Keyword(s):  
Fine Structure ◽  
Cell Membranes ◽  
Freeze Fracture ◽  
Band 3 ◽  
Red Cell ◽  
Band 3 Protein ◽  
Red Cell Membranes

Peptide antisera to human colony-stimulating factor 1 receptor detect ligand-induced conformational changes and a binding site for phosphatidylinositol 3-kinase

1991 ◽  
Vol 11 (5) ◽  
pp. 2489-2495
Author(s):  
J R Downing ◽  
S A Shurtleff ◽  
C J Sherr
Keyword(s):  
Binding Site ◽  
Tyrosine Phosphorylation ◽  
Stable Complex ◽  
Colony Stimulating Factor ◽  
Phosphatidylinositol 3 Kinase ◽  
Lipid Kinase ◽  
Vitro Assay ◽  
Juxtamembrane Region ◽  
Stimulating Factor ◽  
Phosphatidylinositol 3

A peptide antiserum (anti-A) directed to the intracellular, juxtamembrane region (residues 552 to 574) of the human colony-stimulating factor 1 receptor (CSF-1R) precipitated only ligand-activated, native receptors from solution but bound to unstimulated forms after their denaturation. Two peptide antisera (anti-KI1 and -KI2), directed to residues 679 to 700 and 701 to 721, respectively, in the CSF-1R kinase insert (KI) domain and including mapped sites of ligand-induced phosphorylation at Tyr-699 and Tyr-708, bound at least 80% of the receptor molecules expressed in either CSF-1-stimulated or unstimulated cells. Immune complexes formed with anti-KI1, anti-A, or a peptide antiserum to the CSF-1R carboxyl terminus (anti-C-ter) coprecipitated CSF-1R complexed to a phosphatidylinositol 3-kinase (PtdIns 3-K) from CSF-1-stimulated cells, whereas anti-KI2 serum did not. In an in vitro assay, binding of CSF-1R to PtdIns 3-K required receptor tyrosine phosphorylation but not CSF-1R-mediated phosphorylation of the lipid kinase, and the association was specifically blocked by anti-KI2 or antibodies to phosphotyrosine. Neither anti-KI1, anti-A, nor anti-C-ter serum inhibited binding. We conclude that (i) only a minority of ligand-activated receptors form a stable complex with PtdIns 3-K in vivo, (ii) efficient binding of the lipid kinase requires receptor tyrosine phosphorylation within the CSF-1R KI domain, and (iii) a region within the KI domain defined by residues 701 to 721 at least partially overlaps the PtdIns 3-K binding site.

Sign in / Sign up

Export Citation Format

Share Document