Investigations into the occurrence of plant cell surface epitopes in exudate gums

A panel of monoclonal antibodies, derived for the specific recognition of developmentally regulated epitopes of the plasma membranes and cell walls of plant cells, has been characterized in relation to binding activities with samples of exudate gums. The monoclonal antibodies are shown to recognize specifically structural features present in four exudate gums—arabic, karaya, ghatti and tragacanth. Dialysis of the gums and competitive inhibitor ELISAs indicated that the monoclonal antibodies recognize both high and low molecular weight components of each gum. The spatial relationships, and possible overlap, of the arabinogalactan epitopes on the most antigenic gum, gum arabic, have been explored in more detail by means of an epitope mapping technique.