Immunocytochemistry is used for antibody localization of proteins in cells
and tissues. The specificity of the results depends on two independent crit
eria: the specificity of the antibody and of the method used. The antibody
specificity is best determined by immunoblot and or immunoprecipitation. Ab
sorption of the antibody with a protein does not determine that the antibod
y would have bound to the same protein in the tissue, and therefore is not
a good control for antibody specificity. The specificity of the method is b
est determined by both a negative control, replacing the primary antibody w
ith serum, and a positive control, using the antibody with cells known to c
ontain the protein. With the increasing use of immunocytochemistry, it is i
mportant to be aware of the appropriate controls needed to show specificity
of the labeling.