Antigen - Antibody Complexes and the Weal and Erythema Skin Responses.

The smallest amount of purified antibody capable of positive weal and erythema response is of the order of 4 μg N. Antigen-antibody complexes are capable of producing specific weal and erythema reactions with antigen—antibody ratio of 1:1 or above. In these instances antibodies occupied at one or both sites are responsible for this response. Pre-formed antigen–antibody complexes are capable of mediating this response.