What is factor B in the complement system?
Factor B is a component of the alternative pathway of complement. It contains a serine protease (SP) domain, and when activated it provides the catalytic activity of the alternative pathway C3 and C5 convertases.
What is B blood factor?
Factor B is an acute-phase protein. Levels of factor B increase during inflammation. Complement factor B is a single- chain molecule of 764 amino acids (MW of 90 kD), including a leader peptide of 25 amino acids. Factor B provides the catalytic subunit of the C3/C5 convertases of the alternative complement pathway.
How do you confirm complement deficiency?
Initial evaluation for suspected complement deficiency is used to identify the affected pathway and should include testing for CP and TP activity (using the CH50 assay for total hemolytic complement) and AP activity (using the AH50 assay for alternative pathway hemolytic activity).
What functional screening tests can be used to test the complement system?
CH50 and AH50 are the most appropriate primary assays used as screening methods for complement abnormalities. Abnormal results in one or another or both will help direct further testing.
What is the function of complement factor B?
This gene encodes complement factor B, a component of the alternative pathway of complement activation. Factor B circulates in the blood as a single chain polypeptide. Upon activation of the alternative pathway, it is cleaved by complement factor D yielding the noncatalytic chain Ba and the catalytic subunit Bb.
Which is an active subunit of complement factor D?
Upon activation of the alternative pathway, it is cleaved by complement factor D yielding the noncatalytic chain Ba and the catalytic subunit Bb. The active subunit Bb is a serine protease that associates with C3b to form the alternative pathway C3 convertase.
What can be detected by a complement blood test?
A complement blood test is most often used to diagnose or monitor autoimmune disorders such as: Lupus, a chronic disease affecting multiple parts of the body, including the joints, blood vessels, kidneys, and brain Rheumatoid arthritis, a condition that causes pain and swelling of the joints, mostly in the hands and feet
What causes elevated complement levels in the blood?
Some conditions associated with elevated complement can include: Complement activity in the bloodstream is characteristically low in people with active autoimmune diseases such as lupus. However, blood complement levels may be normal or high with RA.