In
the past year there have been a number of articles in Nature and other major
journals that discuss the antibody problem in somewhat apocalyptic terms. In my mind there are only two main issues in
the antibody problem: antibody validation and antibody variability. Both of these issues have straightforward
solutions that do not require any massive influx of cash or massive
restructuring of antibody production.
Antibody validation is the hardest nut to crack and
causes the most confusion. There is no
consensus on what constitutes suitable validation and this is complicated by
the different methods for antibody use.
However, antibody validation is a process like all science where
knowledge increases as more and more work is done with the antibody. As long as the data are clear and the methods
used adequately described, progress in validation will occur with time. Nature’s insistence in its instructions to
authors that antibody validation data be provided is exactly the right path to
be taken. However, none of this progress will matter unless we deal with the
antibody variability problem.
There
are two main reasons for the variability in an antibody’s performance. The first is that once an antibody is found
to have a high demand, many different antibody manufacturers will try to make
their own version of antibody so they can sell it. But all these new antibodies
will differ in unknown and unpredictable ways from the original antibody. Thus validation done on the original antibody
may or not be true for the new antibodies. One way to deal with this problem was recently
suggested by Andrew Chalmers and his colleagues http://f1000research.com/articles/2-153/v2
. They argue that all publications using
commercial antibodies should all report the name of the supplier and the
catalog number of the antibody used.
That way even if a supplier sells many varieties of the antibody a
researcher will be able to order the same antibody that was used in the
publication. This suggestion is being
incorporated into the instructions to authors in more and more journals.
Even though this action would greatly improve
the value of antibody validation, an additional source of antibody variability
would remain. This variability occurs
because even if one buys the same antibody with the same catalog number, one
still often encounters large variability in different lots of the same antibody
obtained from different bleeds of the same animal. There is a very
straightforward fix to this type of variability. The solution is to pool all
the serum collected from the animals. Virtually all lot–to-lot variability can
be eliminated for polyclonal antibodies if this procedure is used. It will no
longer be necessary to reinvent the antibody validation wheel each time an
antibody is used. Thus science can build upon itself as it is supposed to do.
Some
may argue that one should use monoclonal antibodies to eliminate variability.
This is unnecessary and also unwise. It
is unnecessary because for most antibodies a single rabbit can produce a 20-30
year supply of antibody. Only small
percentage of all antibodies sold ever sell more than can be produced by a
single rabbit. It is unwise because
monoclonals cost at least 3X what polyclonals cost and we are unlikely to see a
time in the near future when cost will be irrelevant. Only antibodies with a known, large market
are likely to justify the monoclonal cost and maintenance expense.
Scientists
and journals can fix the validation problem if antibody suppliers will fix the
variability problem. We call this the Antibody Two-Step Solution.
Hope more improvements will be made in terms of the antibody validation.
ReplyDeleteWith the two-step solution, the scientists, the journalists and the protein suppliers should work together to solve that problem.
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