Cytokines

[Vicky Anderson]

Hello, I am an undergraduate student and I have been set some work on
cytokines.  The only question I can't answer is why there are so many of
them.  Is it to do with evolution or necessary for the way they function?
None of the books I can find shed any light on the matter.

I realise it is a question that is supposed to make me think rather than
it being nicely avalible in a book, but I don't even know where to start.

Can anyone help?

Cheers