View source for C3b

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[[Image:Complement pathway.png|thumb|right|270px|The classical and alternative complement pathways.]]
'''C3b''' is a one of the elements formed by the cleavage of [[complement component 3]].

C3b may bind to [[microbe|microbial]] cell surfaces within an organism's body. This can lead to the production of surface-bound C3 convertase and thus more C3b components. Also known as C3bBb, this convertase is similar to soluble C3-convertase except that it is membrane bound. 

Alternatively, bound C3b may aid in [[opsonization]] of the microbe by [[macrophages]].<ref name="GeorgiaImmunology" /> [[Complement receptor 1]] or CR1 on macrophages allows the engaging of C3b covered microbes.

C3b is cleaved into C3c and C3d.

==External links==
* http://www.merck.com/mmpe/sec13/ch163/ch163d.html

{{Complement system}}

[[Category:Complement system]]

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