Biomaterial Database

Blocking of antibody complement-dependent effector functions by streptococcal IgG Fc-receptor and staphylococcal protein A. 1985

C Schalén, and L Truedsson, and K K Christensen, and P Christensen

Using haemolysis in gel, two bacterial IgG-binding substances, an Fc-receptor isolated from group A streptococci type M15, and protein A from Staphylococcus aureus, were shown to inhibit complement-mediated lysis of sheep erythrocytes sensitized with rabbit IgG. When the crude alkaline extracts of ten types of group A streptococci were tested to see whether streptococcal components other than Fc-binding material might affect lysis, the degree of inhibition was found to be correlated with Fc-binding activity. In no case was the lysis of IgM-coated cells inhibited. Opsonophagocytosis experiments showed that both purified streptococcal Fc-receptor and protein A impaired antibody complement-dependent killing by human polymorphonuclear leukocytes of each of two strains of group B streptococci (lacking IgG Fc-receptors). Furthermore, the impairment was ascribable to interference with the fixation of complement to the antibodies, as demonstrated in pre-opsonization experiments with one of the strains. Our results suggest that blocking of the binding of complement to IgG is an important virulence mechanism in Fc-receptor-bearing streptococci and staphylococci.

UI	MeSH Term	Description	Entries
D007074	Immunoglobulin G	The major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of IgG, for example, IgG1, IgG2A, and IgG2B.	Gamma Globulin, 7S,IgG,IgG Antibody,Allerglobuline,IgG(T),IgG1,IgG2,IgG2A,IgG2B,IgG3,IgG4,Immunoglobulin GT,Polyglobin,7S Gamma Globulin,Antibody, IgG,GT, Immunoglobulin
D007075	Immunoglobulin M	A class of immunoglobulin bearing mu chains (IMMUNOGLOBULIN MU-CHAINS). IgM can fix COMPLEMENT. The name comes from its high molecular weight and originally was called a macroglobulin.	Gamma Globulin, 19S,IgM,IgM Antibody,IgM1,IgM2,19S Gamma Globulin,Antibody, IgM
D009504	Neutrophils	Granular leukocytes having a nucleus with three to five lobes connected by slender threads of chromatin, and cytoplasm containing fine inconspicuous granules and stainable by neutral dyes.	LE Cells,Leukocytes, Polymorphonuclear,Polymorphonuclear Leukocytes,Polymorphonuclear Neutrophils,Neutrophil Band Cells,Band Cell, Neutrophil,Cell, LE,LE Cell,Leukocyte, Polymorphonuclear,Neutrophil,Neutrophil Band Cell,Neutrophil, Polymorphonuclear,Polymorphonuclear Leukocyte,Polymorphonuclear Neutrophil
D009895	Opsonin Proteins	Proteins that bind to particles and cells to increase susceptibility to PHAGOCYTOSIS, especially ANTIBODIES bound to EPITOPES that attach to FC RECEPTORS. COMPLEMENT C3B may also participate.	Opsonin,Opsonin Protein,Opsonins,Protein, Opsonin
D010587	Phagocytosis	The engulfing and degradation of microorganisms; other cells that are dead, dying, or pathogenic; and foreign particles by phagocytic cells (PHAGOCYTES).	Phagocytoses
D011817	Rabbits	A burrowing plant-eating mammal with hind limbs that are longer than its fore limbs. It belongs to the family Leporidae of the order Lagomorpha, and in contrast to hares, possesses 22 instead of 24 pairs of chromosomes.	Belgian Hare,New Zealand Rabbit,New Zealand Rabbits,New Zealand White Rabbit,Rabbit,Rabbit, Domestic,Chinchilla Rabbits,NZW Rabbits,New Zealand White Rabbits,Oryctolagus cuniculus,Chinchilla Rabbit,Domestic Rabbit,Domestic Rabbits,Hare, Belgian,NZW Rabbit,Rabbit, Chinchilla,Rabbit, NZW,Rabbit, New Zealand,Rabbits, Chinchilla,Rabbits, Domestic,Rabbits, NZW,Rabbits, New Zealand,Zealand Rabbit, New,Zealand Rabbits, New,cuniculus, Oryctolagus
D011961	Receptors, Fc	Molecules found on the surface of some, but not all, B-lymphocytes, T-lymphocytes, and macrophages, which recognize and combine with the Fc (crystallizable) portion of immunoglobulin molecules.	Fc Receptors,Fc Receptor,Receptor, Fc
D003165	Complement System Proteins	Serum glycoproteins participating in the host defense mechanism of COMPLEMENT ACTIVATION that creates the COMPLEMENT MEMBRANE ATTACK COMPLEX. Included are glycoproteins in the various pathways of complement activation (CLASSICAL COMPLEMENT PATHWAY; ALTERNATIVE COMPLEMENT PATHWAY; and LECTIN COMPLEMENT PATHWAY).	Complement Proteins,Complement,Complement Protein,Hemolytic Complement,Complement, Hemolytic,Protein, Complement,Proteins, Complement,Proteins, Complement System
D004912	Erythrocytes	Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.	Blood Cells, Red,Blood Corpuscles, Red,Red Blood Cells,Red Blood Corpuscles,Blood Cell, Red,Blood Corpuscle, Red,Erythrocyte,Red Blood Cell,Red Blood Corpuscle
D006462	Hemolytic Plaque Technique	A method to identify and enumerate cells that are synthesizing ANTIBODIES against ANTIGENS or HAPTENS conjugated to sheep RED BLOOD CELLS. The sheep red blood cells surrounding cells secreting antibody are lysed by added COMPLEMENT producing a clear zone of HEMOLYSIS. (From Illustrated Dictionary of Immunology, 3rd ed)	Jerne's Plaque Technique,Hemolytic Plaque Technic,Jerne's Plaque Technic,Hemolytic Plaque Technics,Hemolytic Plaque Techniques,Jerne Plaque Technic,Jerne Plaque Technique,Jernes Plaque Technic,Jernes Plaque Technique,Plaque Technic, Hemolytic,Plaque Technic, Jerne's,Plaque Technics, Hemolytic,Plaque Technique, Hemolytic,Plaque Technique, Jerne's,Plaque Techniques, Hemolytic,Technic, Hemolytic Plaque,Technic, Jerne's Plaque,Technics, Hemolytic Plaque,Technique, Hemolytic Plaque,Technique, Jerne's Plaque,Techniques, Hemolytic Plaque