This control determines that the specific properties of the labeled antibody are responsible for the localization. C. Omission of primary or secondary antibodies. D. Use of pre-immune sera. Collection of sera prior to production of primary antisera used in place of the primary antibody will test positive if some component in the immune sera other than the specific IgG is responsible for the binding. Usually it will not be possible to obtain pre-immune serum from the same animal, but it is possible to employ normal serum from the same species.
Most enzyme activity requires tissues to be as fresh as possible. .
Fixatives, if they can be used, should be refrigerator cold to preserve as much enzymatic activity as possible. Some common reactions that cannot survive fixation are acid and alkaline phosphatases and esterases. Pre embedding vs. Postembedding A. Preembedding procedures 1. Permeabalization may be necessary for penetration, but usually results in poor morphology. Time required 2-3 days 2.