We performed antigen retrieval on paraffin-embedded human placenta using citrate buffer and microwaving at 95°C for 15 min with good results.

Our protocol for the antigen retrieval was as follows:

Antigen retrieval with Citrate buffer (pH = 6.0) is performed in the microwave at 5’x5’x5’ (set temperature for 95◦C, variable wattage setting: 6). Warm the Ag retrieval solution to 95◦C before adding slides and running the program. Allow slides to cool to RT in citrate buffer in ice slurry.

STOCK SOLUTIONS (keep at 4◦C)

1 M Citric Acid: Bring 96.2 g citric acid (anhydrous) to 500 ml in ddH2O

1 M NaCitrate Dihydrate: Bring 147.05 g NaCitrate dehydrate to 500 ml ddH2O

WORKING SOLUTION: (lasts ~1 week)

0.9 ml of 1 M Citric Acid

4.1 ml of 1 M NaCitrate Dihydrate (mw: 294.10 g/mol)

pH to 6.0 with 5 N NaOH

Bring final volume to 500 ml with ddH2O