Biomaterial Database

Determination of C4b.C4-bp complex formed by the activation of classical complement pathway using an enzyme-linked immunosorbent assay. 1987

S Ito, and T Fujita, and N Tamura

Department of Immunology, University of Tsukuba, Ibaraki-ken, Japan.

We developed a quantitative enzyme-linked immunosorbent assay (ELISA) for the detection of C4b.C4-bp complex by incubating the sample on anti-C4-bp-coated plate and then developing with HRP-labeled anti-C4. The amount of C4b.C4-bp complex, generated in vivo by the interaction of purified C4b with C4-bp or normal human serum with aggregated human IgG, was measured by the ELISA. The complex, however, rapidly decreased in serum by the action of factor I. Six out of the 100 plasma samples from patients with various diseases were found positive in the ELISA. One plasma sample from a patient with SLE showed high level of C4b.C4-bp complex with decreased levels of factor I, C4, C4-bp and CH50. These results suggest that the detection of C4b.C4-bp complex is useful for monitoring the diseases in which the classical pathway activation is expected.

UI	MeSH Term	Description	Entries
D008180	Lupus Erythematosus, Systemic	A chronic, relapsing, inflammatory, and often febrile multisystemic disorder of connective tissue, characterized principally by involvement of the skin, joints, kidneys, and serosal membranes. It is of unknown etiology, but is thought to represent a failure of the regulatory mechanisms of the autoimmune system. The disease is marked by a wide range of system dysfunctions, an elevated erythrocyte sedimentation rate, and the formation of LE cells in the blood or bone marrow.	Libman-Sacks Disease,Lupus Erythematosus Disseminatus,Systemic Lupus Erythematosus,Disease, Libman-Sacks,Libman Sacks Disease
D002352	Carrier Proteins	Proteins that bind or transport specific substances in the blood, within the cell, or across cell membranes.	Binding Proteins,Carrier Protein,Transport Protein,Transport Proteins,Binding Protein,Protein, Carrier,Proteins, Carrier
D003167	Complement Activation	The sequential activation of serum COMPLEMENT PROTEINS to create the COMPLEMENT MEMBRANE ATTACK COMPLEX. Factors initiating complement activation include ANTIGEN-ANTIBODY COMPLEXES, microbial ANTIGENS, or cell surface POLYSACCHARIDES.	Activation, Complement,Activations, Complement,Complement Activations
D003169	Complement Inactivator Proteins	Serum proteins that negatively regulate the cascade process of COMPLEMENT ACTIVATION. Uncontrolled complement activation and resulting cell lysis is potentially dangerous for the host. The complement system is tightly regulated by inactivators that accelerate the decay of intermediates and certain cell surface receptors.	Complement Cytolysis Inhibiting Proteins,Complement Cytolysis Inhibitor Proteins,Complement Inactivating Proteins,Serum Complement Inactivators,Complement Inactivators, Serum,Inactivating Proteins, Complement,Inactivator Proteins, Complement,Inactivators, Serum Complement,Proteins, Complement Inactivating,Proteins, Complement Inactivator
D003171	Complement Pathway, Classical	Complement activation initiated by the binding of COMPLEMENT C1 to ANTIGEN-ANTIBODY COMPLEXES at the COMPLEMENT C1Q subunit. This leads to the sequential activation of COMPLEMENT C1R and COMPLEMENT C1S subunits. Activated C1s cleaves COMPLEMENT C4 and COMPLEMENT C2 forming the membrane-bound classical C3 CONVERTASE (C4B2A) and the subsequent C5 CONVERTASE (C4B2A3B) leading to cleavage of COMPLEMENT C5 and the assembly of COMPLEMENT MEMBRANE ATTACK COMPLEX.	Classical Complement Pathway,Classical Complement Activation Pathway,Complement Activation Pathway, Classical
D003181	Complement C4	A glycoprotein that is important in the activation of CLASSICAL COMPLEMENT PATHWAY. C4 is cleaved by the activated COMPLEMENT C1S into COMPLEMENT C4A and COMPLEMENT C4B.	C4 Complement,C4 Complement Component,Complement 4,Complement C4, Precursor,Complement Component 4,Pro-C4,Pro-complement 4,C4, Complement,Complement Component, C4,Complement, C4,Component 4, Complement,Component, C4 Complement,Pro C4,Pro complement 4
D004797	Enzyme-Linked Immunosorbent Assay	An immunoassay utilizing an antibody labeled with an enzyme marker such as horseradish peroxidase. While either the enzyme or the antibody is bound to an immunosorbent substrate, they both retain their biologic activity; the change in enzyme activity as a result of the enzyme-antibody-antigen reaction is proportional to the concentration of the antigen and can be measured spectrophotometrically or with the naked eye. Many variations of the method have been developed.	ELISA,Assay, Enzyme-Linked Immunosorbent,Assays, Enzyme-Linked Immunosorbent,Enzyme Linked Immunosorbent Assay,Enzyme-Linked Immunosorbent Assays,Immunosorbent Assay, Enzyme-Linked,Immunosorbent Assays, Enzyme-Linked
D005921	Glomerulonephritis	Inflammation of the renal glomeruli (KIDNEY GLOMERULUS) that can be classified by the type of glomerular injuries including antibody deposition, complement activation, cellular proliferation, and glomerulosclerosis. These structural and functional abnormalities usually lead to HEMATURIA; PROTEINURIA; HYPERTENSION; and RENAL INSUFFICIENCY.	Bright Disease,Kidney Scarring,Glomerulonephritides,Scarring, Kidney
D005922	Glomerulonephritis, IGA	A chronic form of glomerulonephritis characterized by deposits of predominantly IMMUNOGLOBULIN A in the mesangial area (GLOMERULAR MESANGIUM). Deposits of COMPLEMENT C3 and IMMUNOGLOBULIN G are also often found. Clinical features may progress from asymptomatic HEMATURIA to END-STAGE KIDNEY DISEASE.	Berger Disease,Immunoglobulin A Nephropathy,Nephropathy, IGA,Berger's Disease,IGA Glomerulonephritis,IGA Nephropathy,Iga Nephropathy 1,Nephritis, IGA Type,Bergers Disease,Glomerulonephritides, IGA,IGA Type Nephritis,Nephropathy 1, Iga,Nephropathy, Immunoglobulin A
D006023	Glycoproteins	Conjugated protein-carbohydrate compounds including MUCINS; mucoid, and AMYLOID glycoproteins.	C-Glycosylated Proteins,Glycosylated Protein,Glycosylated Proteins,N-Glycosylated Proteins,O-Glycosylated Proteins,Glycoprotein,Neoglycoproteins,Protein, Glycosylated,Proteins, C-Glycosylated,Proteins, Glycosylated,Proteins, N-Glycosylated,Proteins, O-Glycosylated