Receptors on red cells for Plasmodium falciparum and their interaction with merozoites

1984 ◽  
Vol 307 (1131) ◽  
pp. 189-200 ◽  
Keyword(s):  
Plasmodium Falciparum ◽  
Hydrophobic Interactions ◽  
Membrane Lipid ◽  
Red Cells ◽  
Red Cell ◽  
Naturally Occurring ◽  
Electrostatic And Hydrophobic Interactions ◽  
Wheatgerm Agglutinin ◽  
Human Red Cells

The red cell sialoglycoproteins (glycophorins, The red cell sialoglycoproteins (glycophorins, α(A), δ(B) and β and γ(C)) play a crucial role in the invasion of human red cells by merozoites of Plasmodium falciparum . Red cells deficient in any of the glycophorins, including β (also known as glycoconnectin), resist infection by this parasite to varying degrees. These cells and other naturally occurring well-characterized glycophorin variants provide extremely powerful tools to dissect the role of these molecules in invasion. The binding of merozoites to human red cells appears analogous to the binding of wheatgerm agglutinin to sialoglycoconjugates. In both systems O- and N-linked oligosaccharides may be involved. Membrane lipid has not been implicated as a receptor for merozoites, but may instead non-specifically modify binding, as may electrostatic and hydrophobic interactions. The results of data using monoclonal antibodies and lectins, although possibly helpful in identifying specific determinants, must be interpreted with caution. Overall the data suggest that the red cell receptors for all strains of P. falciparum tested to date are located on the glycophorins. Accordingly these putative receptors have been used to affinity-purify complementary parasite components which may yet prove to be of protective immunological significance in a vaccine.

scholarly journals Anatomy of Red Cell Damage by Plasmodium falciparum in Man

Blood ◽  
1972 ◽  
Vol 40 (1) ◽  
pp. 98-104 ◽  
Author(s):  
Stanley P. Balcerzak ◽  
John D. Arnold ◽  
Daniel C. Martin
Keyword(s):  
Plasmodium Falciparum ◽  
Surface Defect ◽  
Surface Defects ◽  
Cell Damage ◽  
Red Cells ◽  
Malarial Parasite ◽  
Red Cell ◽  
Parasite Plasmodium ◽  
Parasite Plasmodium Falciparum ◽  
Human Red Cells

Abstract The manner in which the malarial parasite, Plasmodium falciparum, invades and destroys human red cells is uncertain. Surface and internal anatomy of erythrocytes from subjects with parasitemia was examined in an effort to understand this process better. P. falciparum causes marked distortion of the surface of red cells. In parasitized cells, the bulk of the organism lies under a smooth erythrocyte exterior, but part of it is often associated with a highly irregular red cell surface defect. Many cells without parasites have cavitary surface defects. Their appearance suggests that they previously may have contained parasites. These morphologic observations offer possible explanations for premature destruction of parasitized as well as nonparasitized red cells.

scholarly journals Kinetics and stoichiometry of Na-dependent Li transport in human red blood cells.

1978 ◽  
Vol 72 (2) ◽  
pp. 249-265 ◽  
Author(s):  
B Sarkadi ◽  
J K Alifimoff ◽  
R B Gunn ◽  
D C Tosteson
Keyword(s):  
Transport System ◽  
Red Cells ◽  
Normal Male ◽  
Red Cell ◽  
Red Cell Membrane ◽  
Human Red Blood Cells ◽  
Na Efflux ◽  
Tightly Coupled ◽  
Male Subjects ◽  
Human Red Cells

This paper describes the kinetics and stoichiometry of a tightly coupled Na-Li exchange transport system in human red cells. The system is inhibited by phloretin and furosemide but not by ouabain. Li influx by this system increases and saturates with increasing concentrations of external Li and internal Na and is inhibited competitively by external Na. Comparable functions relate Li efflux and Na efflux to internal and external Li and Na concentrations. Analysis of these relations yields the following values for the ion concentrations required to half-maximally activate the transport system: internal Na and Li 9.0 and 0.5 mM, respectively, external Na and Li 25 and 1.5 mM, respectively. The system performs a 1:1 exchange of Na and Li moving in opposite directions across the red cell membrane. We found no evidence for a simultaneous transport of more than one Na and Li by the system. The maximum transport rate of Na-dependent Li transport varied between 0.1 and 0.37 mmol/(liter of cells X h) in the red cells of the five normal male subjects studied. No significant variations between individual subjects were observed for bicarbonate-stimulated Li transport and for the residual Li fluxes which occur in the absence of bicarbonate and in the presence of ouabain plus phloretin.

pH environmental of red cells in the spleen

1976 ◽  
Vol 231 (6) ◽  
pp. 1672-1678 ◽  
Author(s):  
MJ Levesque ◽  
AC Groom
Keyword(s):  
Splenic Tissue ◽  
Red Cells ◽  
Red Cell ◽  
Cat Spleen ◽  
Flow Through ◽  
Red Pulp ◽  
Reduced Flow

Intrasplenic pH in vivo was deduced from measurements on blood drained from cat spleen during contraction with the inflow occluded. The pH of blood in the red pulp is normally 7.20, but stasis or reduced flow through the pulp causes pH to fall toward 6.8. The splenic pulp contains blood of high hematocrit. To evaluate the role of buffering by the red cells themselves, intrasplenic p/ in red cell-free spleens was, therefore, estimated atering and leaving the spleen during red cell washout. At inflow pH less than 6.8 the outflow pH was raised, at inflow pH = 6.8 there was no change, b,t at inflow pH greater than 6.8 the outflow pH was lowered. These results indicate that the pH environment of red cells in the spleen results indicate that the pH environment of red cells in the spleen results from the interplay of two separate factors: i) pH-determining elements of the splenic tissue that buffer at 6.8, and ii) buffering provided by red cells passing through the pulp.

Acetylcholinesterase in Human Erythroid Cells

1973 ◽  
Vol 12 (3) ◽  
pp. 911-923
Author(s):  
R. J. SKAER
Keyword(s):  
Endoplasmic Reticulum ◽  
Nervous System ◽  
Golgi Apparatus ◽  
Red Cells ◽  
The Other ◽  
Red Cell ◽  
Erythroid Cells ◽  
Cell Replacement ◽  
Kinetics Of ◽  
Human Red Cells

Acetylcholinesterase is present in human red cells but cannot be demonstrated by the copper thiocholine test. The enzyme is revealed, however, in the perinuclear cisterna, endoplasmic reticulum and Golgi apparatus of red cell precursors. It is suggested that 2 forms of the enzyme are present, one of which can be demonstrated by the copper thiocholine test, the other cannot; one form may be the precursor of the other. These observations may cast light on the kinetics of red cell replacement and on the interpretation of the results from the copper thiocholine test on other tissues such as the nervous system.

scholarly journals Pathways for the reduction of oxidized glutathione in the Plasmodium falciparum-infected erythrocyte: can parasite enzymes replace host red cell glucose-6-phosphate dehydrogenase?

Blood ◽  
1986 ◽  
Vol 67 (3) ◽  
pp. 827-830 ◽  
Author(s):  
EF Jr Roth ◽  
S Schulman ◽  
J Vanderberg ◽  
J Olson
Keyword(s):  
Plasmodium Falciparum ◽  
Oxidant Stress ◽  
Reduction Rate ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Red Cells ◽  
Host Cells ◽  
Functional Assay ◽  
Red Cell ◽  
Oxidized Glutathione ◽  
Glucose 6 Phosphate Dehydrogenase

Abstract Plasmodium falciparum-infected human red cells possess at least two pathways for the generation of reduced nicotinamide adenine dinucleotide phosphate (NADPH): (1) the glucose-6-phosphate dehydrogenase (G6PD) pathway and (2) the glutamate dehydrogenase (GD) pathway using glutamate as a substrate. Uninfected erythrocytes lack the GD pathway. The NADPH generated can be used to reduce oxidized glutathione (GSSG), which accumulates in the presence of an oxidative stress. In red cell G6PD deficiency, this pathway is reduced or absent, and the host cells as well as the parasites within them are vulnerable to oxidant stress. In view of the presence of the GD pathway in parasitized red cells and the recent description of a parasite-derived G6PD enzyme, we have asked whether the pathways for the reduction of GSSG provided by the parasite can substitute for the host G6PD in red cells deficient in G6PD activity. We have devised a functional assay in which the reduction rate of GSSG is monitored in the presence of buffered infected or control red cell lysates and substrates. Infected G6PD-deficient erythrocytes were obtained from in vitro cultures after a single prior growth cycle of the parasites in G6PD deficient cells to eliminate contaminating normal red cells. The results show that only parasitized red cells can reduce GSSG via the GD pathway. In parasitized G6PD Mediterranean red cells (completely G6PD-deficient), there is a detectable GSSG reduction via the G6PD pathway, not found in uninfected lysates from the same individual. In G6PD A- (African type, featuring partial deficiency), a small increment in the G6PD-dependent reduction of GSSG can also be detected. However, when compared to G6PD normal red cells, the activities from the parasite-derived pathways are small and could not be considered substitutes for normal host enzyme activity. It is concluded that while the plasmodium provides additional pathways for the generation of NADPH that may serve its own metabolic needs, the host red cells and hence the parasite itself remain vulnerable to oxidant stress.

scholarly journals The Role of Red Cell Energy Metabolism in the Generation of Irreversibly Sickled Cells In Vitro

Blood ◽  
1973 ◽  
Vol 42 (6) ◽  
pp. 835-842 ◽  
Author(s):  
Michael Jensen ◽  
Stephen B. Shohet ◽  
David G. Nathan
Keyword(s):  
Energy Metabolism ◽  
Calcium Metabolism ◽  
Red Cells ◽  
Red Cell ◽  
Hemoglobin S ◽  
Cell Energy ◽  
Incubation Buffer ◽  
Membrane Defect

Abstract An acquired membrane defect is believed to be responsible for the maintenance of the sickled shape in oxygenated irreversibly sickled cells (ISC), because the hemoglobin S in these cells is not in the aggregated, "sickled" state. In the present study, it is demonstrated that the acquisition of the membrane defect in vitro depends on cellular metabolism. Only if cellular ATP is almost completely depleted while the cells are sickled, do they become unable to resume the biconcave disk shape upon reoxygenation. If calcium is omitted from the incubation buffer, ISCs are not generated despite metabolic depletion. This suggests an action of ATP mediated through calcium metabolism similar to that which prevents membrane stiffening in normal red cells. No ISCs were produced by repeated sickling and unsickling. Thus, a membrane alteration occurring as a consequence of metabolic depletion seems to be a more important factor in the generation of ISC than sickling-unsickling induced fragmentation.

Biological Activity of a Semisynthetic Flavonoid, O-(β-Hydroxyethyl)rutoside: Light-Scattering and Metabolic Studies of Human Red Cells and Platelets

1973 ◽  
Vol 19 (1) ◽  
pp. 31-35 ◽  
Author(s):  
J W ten Cate ◽  
N J van Haeringen ◽  
J Gerritsen ◽  
E Glasius
Keyword(s):  
Biological Activity ◽  
Light Scattering ◽  
Platelet Aggregation ◽  
Cell Aggregation ◽  
Red Cells ◽  
Red Cell ◽  
High Concentrations ◽  
Platelet Functions ◽  
Human Red Cells ◽  
Red Cell Aggregation

Abstract The effect of O-(β-hydroxyethyl)-rutoside (HR) on human erythrocyte and platelet functions is reported. Only high concentrations of the compound distinctly inhibited red cell and platelet aggregation induced by ADP and epinephrine. Lower concentrations of HR inhibit [14C8]adenosine incorporation into red cells as well as into platelets. Inhibition occurs at both 0°C and 37°C, presumably because diffusion of [14C8]adenosine is hindered. Phosphorylation of [14C8] adenosine by the platelets is not inhibited by HR. The inhibition of red cell aggregation is reversed by washing the cells with plasma. Collectively, these findings indicate an effect of the compound at the site of the membrane, independent of cellular metabolism

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