Secondary antibody cross reactivity occurs when an antibody raised against one specific antigen successfully binds with a different antigen.

A secondary antibody has a distinct amino acid sequence that influences its affinity for a specific antigen. Cross reactivity occurs when the secondary antibody recognizes two different antigens with similar three-dimensional structural regions or epitopes.

Cross-reactivity can produce inaccurate results and compromise the scientific reproducibility of an experiment. To avoid this, it is crucial to test the secondary antibody for cross-reactivity with closely related proteins before starting an experiment. The cross-adsorption of secondary antibodies can help to prevent cross-reactivity.