The Molecular Basis of the Interaction of Immunoglobulin G with Complement and Phagocytic Cells

1988 ◽  
pp. 91-108
Author(s):  
D. R. Burton
Keyword(s):  
Immunoglobulin G ◽  
Molecular Basis ◽  
Phagocytic Cells

scholarly journals Structural and molecular basis for hyperspecificity of RNA aptamer to human immunoglobulin G

RNA ◽  
2008 ◽  
Vol 14 (6) ◽  
pp. 1154-1163 ◽  
Author(s):  
S. Miyakawa ◽  
Y. Nomura ◽  
T. Sakamoto ◽  
Y. Yamaguchi ◽  
K. Kato ◽  
...  
Keyword(s):  
Immunoglobulin G ◽  
Molecular Basis ◽  
Human Immunoglobulin ◽  
Rna Aptamer ◽  
Human Immunoglobulin G

scholarly journals Intracellular Trafficking and Killing ofStreptococcus pneumoniae by Human Alveolar Macrophages Are Influenced by Opsonins

2000 ◽  
Vol 68 (4) ◽  
pp. 2286-2293 ◽  
Author(s):  
Stephen B. Gordon ◽  
Glen R. B. Irving ◽  
Roderick A. Lawson ◽  
Margaret E. Lee ◽  
Robert C. Read
Keyword(s):  
Streptococcus Pneumoniae ◽  
Membrane Protein ◽  
Alveolar Macrophages ◽  
Immunoglobulin G ◽  
Intracellular Trafficking ◽  
Phagocytic Cells ◽  
Bacterial Viability ◽  
Human Alveolar Macrophages

ABSTRACT Human alveolar macrophages (HAM) are the major resident phagocytic cells of the gas-exchanging areas of the lung. Following contact with macrophages, bacteria enter phagosomes, which gradually acquire the characteristics of terminal phagolysosomes, with incorporation of lysosome-associated membrane protein (LAMP). We measured the binding of type 1 Streptococcus pneumoniae to the surface of HAM and then measured subsequent internalization and phagosomal incorporation of LAMP-1 under various opsonic conditions. Opsonization with serum containing immunoglobulin resulted in significantly greater binding of pneumococci to HAM compared with opsonization with immunoglobulin G (IgG)-depleted serum containing complement, which in turn resulted in marginally increased binding over that observed in the absence of opsonization. Internalization of opsonized S. pneumoniaegradually increased to a maximum of 20% of bound bacteria by 120 min of warm incubation, with 20% of internalized pneumococci being localized within LAMP-containing compartments by 80 min. Internalization of opsonized S. pneumoniae by HAM correlated with a reduction of bacterial viability. When inocula were adjusted so that pneumococcal binding under different conditions was equalized, subsequent internalization, trafficking to LAMP-containing compartments, and reduction of bacterial viability were less efficient in the absence of opsonization than that observed following opsonization with adsorbed or IgG-replete adsorbed serum. Once bound to the surface of HAM, pneumococci opsonized with adsorbed serum with or without IgG were internalized, processed, and killed equally well. In conclusion, binding, intracellular trafficking, and killing of S. pneumoniae by HAM are each significantly increased by opsonization with serum containing immunogloblin and/or complement.

scholarly journals The Intrinsic Immunoglobulin G Endopeptidase Activity of Streptococcal Mac-2 Proteins Implies a Unique Role for the Enzymatically Impaired Mac-2 Protein of M28 Serotype Strains

2008 ◽  
Vol 76 (5) ◽  
pp. 2183-2188 ◽  
Author(s):  
Jenny Johansson Söderberg ◽  
Patrik Engström ◽  
Ulrich von Pawel-Rammingen
Keyword(s):  
Immunoglobulin G ◽  
Ex Vivo ◽  
Cysteine Residue ◽  
Ros Generation ◽  
Ros Production ◽  
Phagocytic Cells ◽  
Fcγ Receptors ◽  
Unique Role ◽  
Endopeptidase Activity ◽  
Bifunctional Proteins

ABSTRACT IdeS, a secreted cysteine protease of the important human pathogen Streptococcus pyogenes, interferes with phagocytic killing by specifically cleaving the heavy chain of immunoglobulin G (IgG). Two allelic variants of the enzyme have been described, the IgG-specific endopeptidase, IdeS (or Mac-1) and Mac-2, a protein with only weak IgG endopeptidase activity, which has been suggested to interfere with opsonophagocytosis by blocking Fcγ receptors of phagocytic cells. However, despite the fact that Mac-2 proteins interact with Fcγ receptors, no inhibition of reactive oxygen species (ROS) production, opsonophagocytosis, or streptococcal killing by Mac-2 has been reported. In the present study, Mac-2 proteins are shown to contain IgG endopeptidase activity indistinguishable from the enzymatic activity exhibited by IdeS/Mac-1 proteins. The earlier reported weak IgG endopeptidase activity appears to be unique to Mac-2 of M28 serotype strains (Mac-2M28) and is most likely due to the formation of a disulfide bond between the catalytic site cysteine and a cysteine residue in position 257 of Mac-2M28. Furthermore, Mac-2 proteins are shown to inhibit ROS production ex vivo, independently of the IgG endopeptidase activity of the proteins. Inhibition of ROS generation per se, however, was not sufficient to mediate streptococcal survival in bactericidal assays. Thus, in contrast to earlier studies, implicating separate functions for IdeS and Mac-2 protein variants, the current study suggests that Mac-2 and IdeS are bifunctional proteins, combining Fcγ receptor binding and IgG endopeptidase activity. This finding implies a unique role for Mac-2 proteins of the M28 serotype, since this serotype has evolved and retained a Mac-2 protein lacking IgG endopeptidase activity.

Renilla Bioluminescence: A Morphologic Approach to the Location of Photocytes

1974 ◽  
Vol 32 ◽  
pp. 208-209
Author(s):  
Ben O. Spurlock ◽  
Milton J. Cormier
Keyword(s):  
Excited State ◽  
Ground State ◽  
Molecular Basis ◽  
Light Emission ◽  
Chemical Basis ◽  
Electronic Excited State ◽  
Colonial Form ◽  
The Common ◽  
Eighteenth And Nineteenth Centuries ◽  
Catalyzed Oxidation

The phenomenon of bioluminescence has fascinated layman and scientist alike for many centuries. During the eighteenth and nineteenth centuries a number of observations were reported on the physiology of bioluminescence in Renilla, the common sea pansy. More recently biochemists have directed their attention to the molecular basis of luminosity in this colonial form. These studies have centered primarily on defining the chemical basis for bioluminescence and its control. It is now established that bioluminescence in Renilla arises due to the luciferase-catalyzed oxidation of luciferin. This results in the creation of a product (oxyluciferin) in an electronic excited state. The transition of oxyluciferin from its excited state to the ground state leads to light emission.

Use of Protein a Conjugated to Peroxidase to Localize Immunoglobulin G in SSPE Ferret Brain

1982 ◽  
Vol 40 ◽  
pp. 350-351
Author(s):  
Hannah R. Brown ◽  
Anthony F. Nostro ◽  
Halldor Thormar
Keyword(s):  
Immunoglobulin G ◽  
Human Disease ◽  
Measles Virus ◽  
Subacute Sclerosing Panencephalitis ◽  
Protein A ◽  
Inflammatory Lesions ◽  
Sspe Virus ◽  
Specific Immunoglobulin ◽  
Antibody Titers ◽  
The Brain

Subacute sclerosing panencephalitis (SSPE) is a slowly progressing disease of the CNS in children which is caused by measles virus. Ferrets immunized with measles virus prior to inoculation with the cell associated, syncytiogenic D.R. strain of SSPE virus exhibit characteristics very similar to the human disease. Measles virus nucleocapsids are present, high measles antibody titers are found in the sera and inflammatory lesions are prominent in the brains. Measles virus specific immunoglobulin G (IgG) is present in the brain,and IgG/ albumin ratios indicate that the antibodies are synthesized within the CNS.

Quantification of Silica Uptake by Alveolar Macrophages - An Emperical Scanning Electron Microprobe Method

1982 ◽  
Vol 40 ◽  
pp. 332-333
Author(s):  
V. V. Damiano ◽  
R. P. Daniele ◽  
H. T. Tucker ◽  
J. H. Dauber
Keyword(s):  
Quantitative Analysis ◽  
Alveolar Macrophages ◽  
Bulk Sample ◽  
Silica Particles ◽  
Empirical Method ◽  
Phagocytic Cells ◽  
Calibration Standards ◽  
X Ray ◽  
Accurate Quantitative Analysis ◽  
Scanning Electron

An important example of intracellular particles is encountered in silicosis where alveolar macrophages ingest inspired silica particles. The quantitation of the silica uptake by these cells may be a potentially useful method for monitoring silica exposure. Accurate quantitative analysis of ingested silica by phagocytic cells is difficult because the particles are frequently small, irregularly shaped and cannot be visualized within the cells. Semiquantitative methods which make use of particles of known size, shape and composition as calibration standards may be the most direct and simplest approach to undertake. The present paper describes an empirical method in which glass microspheres were used as a model to show how the ratio of the silicon Kα peak X-ray intensity from the microspheres to that of a bulk sample of the same composition correlated to the mass of the microsphere contained within the cell. Irregular shaped silica particles were also analyzed and a calibration curve was generated from these data.

Androgen-induced plasticity at a “vocal” neuromuscular synapse

1994 ◽  
Vol 52 ◽  
pp. 32-33
Author(s):  
Darcy B. Kelley ◽  
Martha L. Tobias ◽  
Mark Ellisman
Keyword(s):  
Xenopus Laevis ◽  
Motor Neurons ◽  
Sexual Differentiation ◽  
Molecular Basis ◽  
Neuromuscular Synapse ◽  
Sexually Dimorphic ◽  
Intracellular Protein ◽  
Developmental Program ◽  
Androgen Action ◽  
Clawed Frog

Brain and muscle are sexually differentiated tissues in which masculinization is controlled by the secretion of androgens from the testes. Sensitivity to androgen is conferred by the expression of an intracellular protein, the androgen receptor. A central problem of sexual differentiation is thus to understand the cellular and molecular basis of androgen action. We do not understand how hormone occupancy of a receptor translates into an alteration in the developmental program of the target cell. Our studies on sexual differentiation of brain and muscle in Xenopus laevis are designed to explore the molecular basis of androgen induced sexual differentiation by examining how this hormone controls the masculinization of brain and muscle targets.Our approach to this problem has focused on a highly androgen sensitive, sexually dimorphic neuromuscular system: laryngeal muscles and motor neurons of the clawed frog, Xenopus laevis. We have been studying sex differences at a synapse, the laryngeal neuromuscular junction, which mediates sexually dimorphic vocal behavior in Xenopus laevis frogs.

A molecular basis for opiate action

1998 ◽  
Vol 33 ◽  
pp. 65-77 ◽  
Author(s):  
Dominique Massotte ◽  
Brigitte L. Kieffer
Keyword(s):  
Molecular Basis
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