Immunadsorptionsassays

Immunoadsorption assays are a family of immunoassays that use an immunoadsorbent—a solid support bearing an immobilized antibody or antigen—to selectively bind and isolate a target molecule from a complex sample. The principle relies on the specific interaction between an antibody and its antigen. In a typical setup, the sample is incubated with the immunoadsorbent so that the target binds; after washing, the bound target is detected directly with a labeled reagent or eluted and quantified by an external assay. The reverse configuration uses immobilized antigen to capture specific antibodies, which are then detected or quantified.

Formats include solid-phase capture assays such as enzyme-linked immunosorbent assays that involve an adsorbed capture molecule, as well as flow-through immunoadsorption columns used for purification or depletion of target molecules from plasma or serum. The method can be batch-based or column-based and may employ different detection schemes such as colorimetric, fluorescent, luminescent signals, or mass spectrometric readouts.

Applications of immunoadsorption assays span clinical diagnostics, research, and therapeutics. They are used to measure or characterize antibodies (for example, anti-HLA or autoimmune antibodies) and to monitor immune responses. In therapeutic contexts, immunoadsorption can be employed to deplete pathogenic antibodies from patient plasma, or to purify antigens or antibodies for downstream analyses.

Advantages include high specificity and the ability to concentrate low-abundance targets from complex matrices, with potential for automation and reduced interference. Limitations involve the need for high-quality capture reagents and immobilization chemistry, possible nonspecific binding, and capacity constraints of the immunoadsorbent, all of which can affect assay sensitivity and reproducibility.