Dear Ciprian
 
You have note specified your problem totally.
 
If you have problems with crossover of the fluorophore-emissions in your
microscope Martin W. Wessendor's answer is adequate.
 
But if you have crossover activities of your second step antibodies you
need to specify the specifity of them.
 
Further, you did not specify the antibody against synaptophysin.
 
Lars Bjork
Dept. Immunology
Stockholm University