Complement System

[xClashx]

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The complement system has a C3 convertase. Some books say it is made up of C4b2a and others (first aid) says it is made up of C4b2b.

Apparently the nomenclature changed from C2a to C2b according to first aid.

Is there some sort of consensuses on this?

 

[andrek82]

I did a brief pubmed.com search and could not verify your first aid info. All the info I saw stated that c2 is cleaved to form c2a and c2b. C2a binds c4b and is the catalytic subunit of c3 convertase while c4b is the binding subunit. As for c2b, it seems to be released into serum. I'm sure it had another purpose, but I don't know what that is.

 

[Psai]

It doesn't matter. You need to know what is the classical, what is the alternative, lectin, what complement does, mac, what happens if it is deficient.

 

[andrek82]

It doesn't matter. You need to know what is the classical, what is the alternative, lectin, what complement does, mac, what happens if it is deficient.

I would usually agree with this about most topics, but I felt like the complement system was beaten into me by my Step 1. Obviously there are many possible question combinations, so I'm probably biased, but it seemed very picky.

 

[Psai]

No one's going to test you if the convertase is c2a or c2b. You should know about c3a and c5a being anaphylotoxins, c5a causing degranulation of mast cells, c5b-9 is the mac complex, etc. There are things that are important and things that are not

 

[scoKraz4]

It is the same thing. The nomenclature did change. I never saw a question differentiating the two. Just take note of it i guess

 

[Goro]

Try looking at some Immunology texts instead of Step I (which is filled with errors).

I do sympathize with you. The Immunologists do seem to speak an entirely different language.

 

[GaiusOctavius]

We learned C4b2a. My guess is typo in FA.

 

[sunealoneal]

Not a typo. Our professor brought this up earlier this week. There was apparently some discussion in the past about changing the naming system to reflect the size of the molecule rather than the order discovered. I don't recall which one was supposed to reflect which. At any rate, knowing them both won't be the worst thing in the world.

Edit: I believe Janeway says C4b2b.