mono vs polyclonals; cross-reactions

dLee dLee at CCMAIL.LLU.EDU
Fri Mar 18 12:46:43 EST 1994


>There are lots of conjugated polyklonals that discriminate
>IgG1 and IgG2b, what about the cross reactions?

Polyclonals made to discriminate between these two must be adsorbed or
absorbed against the other subclasses in order to be specific, since
any immunization with one IgG class will generate antibodies to
both class-specific and subclass-specific epitopes.  If absorbed on a
column, the resulting polyclonal should be ok, but if adsorbed
directly, the immune complexes will be left in the Ab solution and may
create problems.

>There are some monoklonal 2nd ABs (only one red) available.
>I suppose  they are much more specific but expensive and all
>from rat. Could there occur other cross reactions e.g.
>Rat at IgG2b binding to a RatIgG2b at MouseIgG1??

Since rat and mouse are genetically close, and immunizations rarely
induce autoantibodies, a rat mAb against mouse IgG2b will have been
selected (during the initial immunization/antibody response) for
epitopes which rat does not have in common with the mouse.  The
cross-reaction you describe above would be very unlikely.

>What system should I use monoclonal or polyclonal and are there
>other tricks to get good results in this case?

Extended incubations in the cold at low antibody concentrations has
been, in our experience, the general rule for the best combination of
sensitivity and specificity.


*********************************************************************
Dean Lee                        * We dance 'round in a ring         *
Dept of Micro and Mol Genetics  * and suppose,                      *
Loma Linda University           * But the secret sits in the middle *
dLee at ccmail.llu.edu             * and knows.               R. Frost *
*********************************************************************



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