1 mab - 2 different proteins?

Dr M.R. Clark mrc7 at cus.cam.ac.uk
Wed Feb 15 06:06:09 EST 1995

In article <D3zun1.Jw2 at freenet.carleton.ca>,
Marc Savard <af423 at FreeNet.Carleton.CA> wrote:
>In a previous posting, Dirk Mielenz (fn162 at fim.uni-erlangen.de) writes:
>> Hi all,
>> has anyone ever heard of a monoclonal antibody recognizing
>> two completely different and unrelated proteins?
>> I don't think that the posibility of one certain epitope 
>> consisting of 4-6 amino acids (perhaps additionally N-
>> or O-glycosylated) occuring in two different proteins
>> is that low. If one looks at possible permutations for
>> a row of 4 to 6 amino acids out of 20, the number
>> should be relatively low compared to the number of
>> existing proteins. I've been thinking about that problem
>> because it might be that we have such a mAb 
>> in our lab.I'd be very glad if anyone has literature hints. 
>> Thanks in advance,
>> Dirk
>It is not sufficient to have an identical row of amino acids.
>You also need the same conformation, i.e. the same 3-D shape.
>But it is probably still possible.
There are in fact many observations of the same monoclonal antibody binding
to two or more different "antigens". As pointed out above it is to be
expected. People who screen peptide libraries, or expression libraries with
antibodies often pull out sequences unrelated to the original antigen.
Sometimes these are called "mimitopes". I know of many people who have
attempted to use antibodies to clone the genes encoding their antigen and
who have ended up with something quite unrelated. Most of these people
haven't published their work in the literature. You don't get much credit
for "Failure to clone the gene encoding xxxxx".

  o/ \\    //            ||  ,_ o   Mike Clark, mrc7 at cus.cam.ac.uk
 <\__,\\  //   __o       || /  /\,  Cambridge University, Dept. Pathology
  ">    ||   _`\<,_    //  \\ \> |  "to pay for my hobbies I have to work
   `    ||  (_)/ (_)  //    \\ \_    as an antibody engineer"

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