Run your first antibody, I do DAB first, develop chromogen, rinse, then
rinse with buffer,  quench again with peroxidase blocker to get rid of any
residual HRP brought into protocol with SA-HRP reagent, rinse, do an
avidin/biotin quench for the same reason, then come back and use your
second antibody, secondary, SA-HRP, second chromogen.

I would do my least sensitive antibody with DAB for better detection.






Gayle Callis
Veterinary Molecular Biology
Montana State University
Bozeman MT 59717-3610
406 994-4705
406 994-4303