avidin D 0.01% in PBS, available from Sigma

d-biotin 0.005% in PBS, available from Sigma

You could probably add sodium azide 10 - 15 mM to the PBS to preserve the
solutions

avidin solution 15 - 20 min
rinse well
biotin solution 15 - 20 min
rinse well

Times for avidin and biotin block and rinses can be extended if desired,
and dependent on the IHC method (seeing differences in some protocols)
Gayle Callis
Veterinary Molecular Biology
Montana State University
Bozeman MT 59717-3610
406 994-4705
406 994-4303