Investigations of fading of immunofluorescence objects.

Fading of immunofluorescent objects was influenced by attenuation of fluorescence intensity whether by attenuation of excitation, post-fixation or counterstaining. In comparison with the wide-band excitation, narrow-band excitation had an influence on the fading rate via the attenuation of the excitation intensity only. Compared with aqueously immersed objects we obtained only half of the intensity and a quite stronger decrease of fluorescence with dry objects or objects embedded with fast-hardening medium. Addition of thiosulphate to embedding medium had no effect on fading. In opposite literature we found in our immunofluorescence specimen after addition of dithionite an extremely increased fading rate.