What does the term 'elution' refer to in immunology?

In immunology, the term 'elution' specifically refers to the process of washing a substance that is bound to another, in order to extract or separate the bound substance. This process is commonly used in laboratory techniques to recover antibodies, antigens, or other biomolecules that have been attached to a solid phase, such as during immunoprecipitation or affinity chromatography.

During elution, a solution (often called an elution buffer) is used to disrupt the interactions between the bound substance and the solid phase, allowing the desired biomolecule to be released into the solution. This technique is essential for many immunological assays, as the ability to retrieve specific antibodies or antigens is crucial for further analysis or testing.

The other options describe different aspects of immunology but do not accurately define the concept of elution. For instance, the binding of antigens and antibodies involves the initial interaction and does not encompass the releasing aspect central to elution. Similarly, the activation of white blood cells and the formation of immune complexes are important processes within the immune response but are distinct from the concept of elution, which focuses solely on extracting substances from a bound state.