Attempts to establish the antigen-antibody theory of epidermal contact hypersensitivity on a sound experimental basis have not been entirely successful. Demonstration of the existence of antibodies would prove the correctness of the theory; consequently, most of the recent work has been designed to detect their presence. They may occur in the serum, or they may be firmly attached to the cell wall (sessile antibodies), or they may be carried by leukocytes. The experimental evidence for the occurrence of antibodies in each of these sites is as follows.
Attempts to Demonstrate the Existence of Antibodies
Serum Antibodies.—Direct attempts to demonstrate the presence of antibodies in serum by flocculation tests in vitro have always failed. In passive transfer experiments a few positive results have been claimed with the Prausnitz-Küstner technique, but Leider and Baer (1948) and Haxthausen (in Loewenthal's "The Eczemas," 1954) pointed out such reports