When an antibody molecule (against one antigen) can combine with (bind to) a different (second) antigen. This sometimes occurs because the second antigen’s molecular structure (shape) is very similar to that of the first antigen.
A reaction between an antibody and an antigen that is similar to the specific antigen for which the antibody was created. It enables immunoglobulins to cross-link and activate B cells.
In the context of blood testing, a reaction can take place when a disease-causing agent interacts with a specific antibody intended for a different disease-causing agent.
A response involving an antibody and an antigen that’s closely related but not exactly the same as the specific antigen. In hypersensitive skin, exposure to such an antigen can lead to symptoms like swelling, fluid accumulation, redness, or a skin rash.