scholarly journals Availability of Complement Bound to Staphylococcus aureus To Interact with Membrane Complement Receptors Influences Efficiency of Phagocytosis

2003 ◽  
Vol 71 (2) ◽  
pp. 656-662 ◽  
Author(s):  
K. M. Cunnion ◽  
H.-M. Zhang ◽  
M. M. Frank
Keyword(s):  
Staphylococcus Aureus ◽  
Human Serum ◽  
Absolute Number ◽  
Normal Human Serum ◽  
Complement Receptor ◽  
Complement Receptors ◽  
Immune Adherence ◽  
Normal Human ◽  
Complement Receptor 1 ◽  
Polysaccharide Capsules

ABSTRACT Complement-mediated opsonization of encapsulated Staphylococcus aureus (CP+) of the predominant capsule types, 5 and 8, remains poorly understood. Our previous work showed that complement is important for mouse survival of CP+ type 5 bacteremia and that the type 5 capsule inhibits the binding of opsonic C3 fragments to the organism. The importance of complement-mediated opsonization of CP+ was tested by neutrophil phagocytosis assays. Complement-mediated opsonization of CP+ increased phagocytosis by 57% compared to opsonization in complement-inhibited serum. Agar-grown CP+, enhancing capsule expression, was phagocytosed only one-tenth as well as the capsule-negative organisms (CP−), supporting the belief that staphylococcal polysaccharide capsules impair phagocytosis. Despite relatively poor phagocytosis of CP+ compared to CP−, complement activation increased the phagocytosis of CP+ by 103%. Thus, complement in normal human serum may have an important role in opsonizing CP+, even when capsule expression is strong. The ability of bound C3 fragments to interact with complement receptor 1 (CD35) on the membrane of human erythrocytes was tested in an immune adherence assay. S. aureus capsule was able to mask C3 fragments on the organism from binding to complement receptor 1. The inhibition of C3 binding to CP+ and the masking of deposited C3 fragments caused by the presence of capsule was associated with markedly decreased phagocytosis. The addition of anti-capsule antibodies to normal human serum was found to markedly improve the recognition of deposited C3 fragments by complement receptor 1 even when the absolute number of C3 molecules bound to S. aureus was not increased.

scholarly journals Natural Antibodies in Normal Human Serum Inhibit Staphylococcus aureus Capsular Polysaccharide Vaccine Efficacy

2012 ◽  
Vol 55 (9) ◽  
pp. 1188-1197 ◽  
Author(s):  
David Skurnik ◽  
Andrea Kropec ◽  
Damien Roux ◽  
Christian Theilacker ◽  
Johannes Huebner ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Human Serum ◽  
Vaccine Efficacy ◽  
Capsular Polysaccharide ◽  
Polysaccharide Vaccine ◽  
Natural Antibodies ◽  
Normal Human Serum ◽  
Normal Human

scholarly journals RECEPTOR FOR SOLUBLE C3 AND C3b ON HUMAN LYMPHOBLASTOID (RAJI) CELLS

1974 ◽  
Vol 139 (3) ◽  
pp. 696-711 ◽  
Author(s):  
Argyrios N. Theofilopoulos ◽  
Viktor A. Bokisch ◽  
Frank J. Dixon
Keyword(s):  
Cell Membrane ◽  
Human Serum ◽  
Cell Membranes ◽  
Raji Cell ◽  
Membrane Damage ◽  
Normal Human Serum ◽  
Serum Factors ◽  
Raji Cells ◽  
Immune Adherence ◽  
Normal Human

This study describes the presence of a receptor for fluid phase human C3 and C3b on Raji cell membranes. The binding of C3 and C3b was demonstrated indirectly by a fluoresceinated anti-C3 serum and directly by using radioiodinated proteins. No other complement proteins or serum factors were needed to mediate binding of C3 and C3b to the receptor. The possibility of enzymatic cleavage of C3 before or after its attachment on the cell membrane was ruled out by the demonstration of antigenically intact C3 on Raji cells. Inhibition and dissociation of Raji cell-EAC1423 rosettes by C3 and C3b indicated that both of these proteins bind to the same receptor site or closely associated receptor sites on Raji cells. C3b-bearing Raji cells were immune adherence negative, indicating that C3b binding to the receptor is brought about through the immune adherence region of the molecule and not the C3d portion. The C3 receptor on Raji cell membranes is uniformly distributed and can move on the membrane plane. Approximately 4 x 105 molecules of C3 or C3b bind per Raji cell. The receptor had a higher affinity for C3 than C3b, as was shown by uptake experiments and inhibition of Raji cell-EAC1423 rosette formation. Apart from the described receptor for C3 and C3b another specific receptor for C3b inactivator-cleaved C3b (C3d) bound to red cells was shown to be present on Raji cells. Raji cells cultured in medium containing fresh normal human serum and cobra venom factor were lysed. Similar results were obtained when C3b-bearing Raji cells were cultured in medium with fresh normal human serum. The lytic effect could be abolished by inactivating serum C3 proactivator (C3PA) and required C6. It was concluded that C3b bound to the Raji cell membrane activates the complement system through the alternate pathway and results in membrane damage and cytolysis. It is postulated that cell destruction by this mechanism may play an important role in vivo in controlling cell growth.

Evaluation of a commercially available radioimmunoassay kit for measurement of doxorubicin in plasma.

1982 ◽  
Vol 28 (1) ◽  
pp. 119-121 ◽  
Author(s):  
E Piall ◽  
G W Aherne ◽  
V Marks
Keyword(s):  
Human Serum ◽  
Normal Human Serum ◽  
Nonspecific Effects ◽  
Normal Human ◽  
Doxorubicin Concentration

Abstract We evaluated a commercially available (Diagnostic Biochemistry Inc.) doxorubicin 125I radioimmunoassay kit. This kit gave a high apparent doxorubicin concentration (greater than 12 micrograms/L), which was not linearly related to dilution, for two pools of normal human serum and plasma and also for samples collected from patients before they received the drug. In contrast, a doxorubicin 3H radioimmunoassay developed by us gave a low blank (2 micrograms/L), which was linearly related to dilution, for the same pools and patients' samples. Doxorubicin concentrations in the plasma of patients receiving the drug were compared by the two methods; the kit gave results five- to 10-fold those obtained with our assay. High nonspecific interference by serum and plasma as measured by the 125I radioimmunoassay must therefore be borne in mind by users of the kit, and we suggest that results should be corrected for these nonspecific effects.

The Presence of Two Forms of Insulin in Normal Human Serum

Biochemistry ◽  
1963 ◽  
Vol 2 (2) ◽  
pp. 286-289 ◽  
Author(s):  
Walter N. Shaw ◽  
Eldon W. Shuey
Keyword(s):  
Human Serum ◽  
Normal Human Serum ◽  
Normal Human
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