Thats obviously not the case.
Weve got lots and lots and lots of antibodies that recognize lots and lots and lots of different things!
Kevin has a post up at We Beasties on some of the initial stages of antibody development, V-(D)-J recombination!
Quick summary (GO READ HIS POST DONT READ JUST READ MY TWO SENTENCE SUMMARY!): A basic ‘antibody’ is composed of two heavy chains (blue) and two light chains (red) to make that ‘Y’ shape you think of when you think ‘antibody’.
How those heavy chains and how those light chains are made requires the DNA of B-cells to be cut and pasted back together again. Im not going over that in much detail because Kevin did. But I will focus on one of Kevins figures.
There are lots of green squares and red squares and purple squares! WAT IZ DAT???
Why, its Evilutionists old friend, Gene Duplication!
There are a whole bunch of different ‘V’ portions of the heavy chain, a bunch of different ‘D’s and a bunch of different ‘Js’. But the heavy chain of an antibody is only composed of one V and one D and one J! So you get lots of variations from all the combinations of V-(D)-J you can make! AND you have two of those V-D-J clusters– One on the chromosome you got from Mom, and one on the chromosome you got from Dad, so theres even more diversity there!
The same happens with the ‘V’s and ‘J’s of the light chains, except you actually have two light chain loci in your chromosome to the heavy chains one, which means four different sets when you consider the chromosome you got from Mom + Dad.
If there was no way to ‘add new information to the genome’, as Creationists say, then you would really only have one antibody. But thanks to the new information added by gene duplication, you not only have antibodies with different butts (that would only get us up to eight antibodies), also thanks to gene duplication you have a GAZZILLION different antibodies because all those duplications can combine in different ways to make different antibodies!
See? Immunology doesnt have to be that scary! If you ‘get’ evilution, you ‘get’ more immunology than you might think!