An immunocytochemical method for histamine detection.

An anti-histaminic immune serum, prepared in New Zealand male rabbits by immunization with a chemospecific antigen (diazotized para-amino-benzoyl-azohistamine) was labeled with fluorescein isothiocyanate for the purpose of histamine detection or was employed for demonstration of histamine using fluorescein-labeled protein A. The IgG fraction of the hyperimmune serum was isolated, purified, and tested for specificity by binding to 3H-histamine or to histamine-containing or histamine-treated cells. Histological preparations used for detection of histamine should be fixed preferably in Carnoy solution. The procedure can also be employed for ultra-histochemical detection of histamine, using ferritin-conjugated antibody or the peroxidase technique.