What does C3 nephritic Factor do?
Also known as: C3NEF C3 nephritic factor is an autoantibody to the alternate complement pathway’s C3 convertase, C3bBb. C3NF stabilises this enzyme leading to an increase in the rate that C3 is activated (measured in this assay by an increase in C3c).
What is nephritic Factor activity?
Nephritic factors The typical nephritic factor is an IgG autoantibody that binds to the alternative pathway convertase called C3bBb. Nephritic factor stabilizes and prolongs the activity of the enzyme by interfering with normal factors controlling the convertase activity.
What is C3 nephropathy?
C3 glomerulonephritis (C3GN) is a recently described entity that shows a glomerulonephritis on light microscopy (LM), bright C3 staining and the absence of C1q, C4 and immunoglobulins (Ig) on immunofluorescence microscopy (IF), and mesangial and/or subendothelial electron dense deposits on electron microscopy (EM).
What is C3NeF?
C3NeF is an autoantibody of C3 convertase (C3bBb) and is often detected in the serum of hypocomplementaemic MPGN patients. Serum samples from 104 non-hypocomplementaemic MPGN patients (C3NeF) were studied. C3NeF, which cannot activate the alternative pathway, was found in the sera of 6 patients.
What causes C3 glomerulonephritis?
Complement 3 glomerulopathy (C3G) is a rare kidney disease that has two forms: dense deposit disease (DDD) and C3 glomerulonephritis (C3GN). Each is caused by genetic or acquired problems in controlling the body’s complement system, which helps fight infections. Genetic problems can be inherited or not inherited.
What causes Hypocomplementemia?
Acquired hypocomplementemia may occur in the setting of bone infections (osteomyelitis), infection of the lining of the heart (endocarditis), and cryoglobulinemia. Systemic lupus erythematosus is associated with low C3 and C4. Membranoproliferative glomerulonephritis usually has low C3.
What enzyme can cleave C3?
Convertase enzymes fulfill a central role in the complement cascade as they cleave C3 and C5, which mediate nearly all complement effector functions. C3 convertases cleave C3 into C3a, a chemoattractant molecule, and C3b, which covalently binds to target surfaces and triggers phagocytosis.
How is C3 cleaved?
In the alternative complement pathway, C3 is cleaved by C3bBb, another form of C3-convertase composed of activated forms of C3 (C3b) and factor B (Bb). The resultant complex, C3bBb, is called the alternative pathway (AP) C3 convertase.
Is C3 nephritic factor associated with mesangiocapillary glomerulonephritis type II?
The association of a C3 splitting activity, known as C3 nephritic factor (C3NeF), with mesangiocapillary glomerulonephritis (MCGN), especially MCGN type II, has long been known.
What is another nephritic factor (c4nef)?
Another nephritic factor has been characterized by the ability to stabilize C5 convertase of the alternative pathway (C5NeF). In addition, there are autoantibodies against assembled C3/C5 convertase of the classical and lectin pathways (C4NeF).
What does c3nef stand for?
The first nephritic factor described with the capacity to stabilize C3 convertase of the alternative pathway was C3 nephritic factor (C3NeF). Another nephritic factor has been characterized by the ability to stabilize C5 convertase of the alternative pathway (C5NeF).
What are neonephritic factors?
Nephritic factors comprise a heterogeneous group of autoantibodies against neoepitopes generated in the C3 and C5 convertases of the complement system, causing its dysregulation. Classification of these autoantibodies can be clustered according to their stabilization of different convertases either from the classical or alternative pathway.