Immunoregulatory Roles for Fc Receptor-Like Molecules

2010 ◽  
pp. 89-104 ◽  
Author(s):  
Götz R. A. Ehrhardt ◽  
Max D. Cooper
Keyword(s):  
Fc Receptor

Ultrastructural study of cytoskeletal interactions with endosomes in macrophages by quickfreezing and deep-etching method

1990 ◽  
Vol 48 (3) ◽  
pp. 576-577
Author(s):  
Takeshi Baba ◽  
Nobuki Shiozawa ◽  
Masao Hotch ◽  
Shinichi Ohno
Keyword(s):  
Immune Complex ◽  
Ultrastructural Study ◽  
Fc Receptor ◽  
Coated Pits ◽  
Deep Etching ◽  
Receptor Mediated Endocytosis ◽  
Etching Method ◽  
Quick Freezing

Endosomes are vesicular or tubular organelles that play important roles in transports of receptors and receptor―bound ligands during receptor-mediated endocytosis. The mechanisms of endocytic transports from clathrin-coated pits to lysosomes have been studied by many investigators. However, few studies were reported about the interactions between endosomes and cytoskeletons. In this study, Fc-receptor-mediated endocytosis in macrophages are investigated by quick-freezing and deep-etching (QF-DE) method combined with gold-labeled immune complex and “replica scraping method”.

Calcium and the Fc Receptor on Human Platelets

1987 ◽  
Vol 57 (03) ◽  
pp. 298-301
Author(s):  
William F Clark ◽  
Gerald J M Tevaarwerk ◽  
Bruce D Reid ◽  
Suzanne Hall ◽  
Anita Caveney ◽  
...  
Keyword(s):  
Specific Binding ◽  
Normal Subjects ◽  
Human Platelets ◽  
Fc Receptor ◽  
Normal Male ◽  
Scatchard Analysis ◽  
Normal Female ◽  
Apparent Difference ◽  
Binding Data ◽  
Direct Binding

SummaryWe have described the calcium dependence of the IgG Fc receptor (Fc-R) on human platelets by analyzing the direct binding of radiolabelled Fc fragments, monomers and dimers of IgG. Specific binding to platelets was undetectable at 37° C in a calcium-free preparation but readily detected when calcium was restored. Scatchard analysis of the binding data for the calcium-restored platelets permitted calculation of the available Fc-R and the Ka of binding for the different IgG ligands. The mean Ka of binding for 12 normal subjects varied from 107 to 108 L/M, with an equal receptor number measured by Fc fragments and dimers of IgG, but a lesser amount for monomeric IgG. There was no apparent difference in Fc-R number for platelets from 6 normal male versus 6 normal female subjects.At 4° C binding was detectable for dimers and polymers of IgG in a calcium-free preparation and this was markedly increased with recalcification. Thus, our data are consistent with an Fc receptor population on human platelets whose avidity for binding is significantly enhanced in a calcium-restored medium.

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