What is Pre Adsorption?
Pre adsorption is a technique used in histology to improve the specificity of antibodies used in immunohistochemical staining. It involves the incubation of an antibody with an excess of its specific antigen before applying it to the tissue sections. This process helps to block any non-specific binding and enhances the accuracy of the staining results.
Why is Pre Adsorption Important?
The primary goal of pre adsorption is to reduce non-specific background staining, which can obscure the interpretation of the tissue sample. Non-specific binding can occur due to various reasons, including
cross-reactivity with similar antigens or
non-antigenic interactions with tissue components. By pre-adsorbing the antibody, any antibodies that would bind non-specifically are neutralized, allowing only the specific antibodies to bind to their target antigens.
The antibody is incubated with an excess of its specific antigen, often in a solution.
This mixture is allowed to incubate for a specified period, usually at a controlled temperature.
The pre-adsorbed antibody-antigen complexes are then removed, typically by centrifugation or filtration.
The supernatant, containing the pre-adsorbed antibody, is then used for immunohistochemical staining.
There is a high degree of
background staining in control sections.
The antibody shows cross-reactivity with other proteins or antigens.
Specificity of the antibody needs validation in a new tissue type or species.
Improved specificity and reduced non-specific binding.
Enhanced signal-to-noise ratio, resulting in clearer and more interpretable images.
Increased confidence in the results obtained from
immunohistochemical staining.
It requires access to the specific antigen, which may not always be available.
The process can be time-consuming and may require optimization for different antibodies.
There is a risk of losing some of the antibody’s
binding affinity during the pre adsorption process, which can affect the sensitivity of the staining.
Each of these methods has its own advantages and can be used in conjunction with pre adsorption to achieve optimal results.
Conclusion
Pre adsorption is a valuable tool in histology for enhancing the specificity and reliability of immunohistochemical staining. By understanding and implementing this technique, researchers can achieve more accurate and interpretable results in their studies. Despite some limitations, the benefits of pre adsorption make it a crucial step in many histological applications.
