Antigen retrieval fluids

The above discussion indicates that although 0.01 M sodium citrate buffer (pH 6.0) is commonly used, it is not a universally ideal antigen retrieval fluid for all types of tissues and antigens. If published information is not available with regard to the best antigen retrieval fluid for the antigen under study, the ideal retrieval fluid for each type of epitope must be determined by trial and error. 

The following four antigen retrieval fluids are commercially available (BioGenex, San Ramon, CA). The approximate pH indicated below is valid at the time of manufacture the pH of the fluid may change during storage. 

Antigen Retrieval Citra Microwave Solution used at pH 6.0. 

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Other commercial sources for antigen retrieval fluids are ... 

There are many reasons for the lack of consensus on this highly complex phenomenon, and they are discussed below. Various studies mentioned above were conducted using different parameters of antigen retrieval methods, including antigen retrieval fluids, pH, heat source, temperature, and duration of treatments for detecting different antigens. The type of fixation and duration of fixation also varied in these studies. Other variants were the type of epitope and antibody and source of antibodies used. 

In contrast to microwave heating, steam treatment heats slides slowly to a uniform temperature. This avoids boiling the antigen retrieval fluid and minimizes section detachment from slides. Steam heat used in combination with EDTA and protease digestion has been... 

Overheating the microwave oven tends to result in boiling or excessively rapid evaporation of fluids such as ethanol used for dehydration, formaldehyde employed for fixation, and the antigen retrieval fluid. As a result, flammable and/or toxic materials are released in the microwave oven. Even without overheating, vapors are produced because containers are kept open in the oven to prevent pressurization. Transparent microwave containers should be used, fluid volumes should be -100ml. Microwave ovens with attached efficient extractor fans are commercially available, as are microwave ovens with temperature probes. To avoid possible exposure to toxic vapors, the face should be turned away when the oven door is opened (Horobin and Fleming, 1990). The oven door should not be opened or closed to turn the microwave power on and off. 

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