Immunologic Memory Of Phytohemagglutinin-Stimulated Lymphocytes

Using the technic of bacterial adherence, in which circumferential adhesion of microorganism to the lymphocyte surface indicates antibody production by this cell, phytohemagglutinin (PHA)-stimulated lymphocytes reacted differently towards E.coli, a natural, lifelong immunogen, and towards Salmonella, one which is acquired and overtly given when the need arises. Bacterial adherence after cell culture was markedly augmented in terms of numbers of participating organisms and cells when PHA-provoked lymphoblasts, rather than small, unchanged lymphocytes, were incubated with E.coli. In contrast, this type of response either did not occur at all or only in a limited, transient fashion when Salmonella was substituted as the laboratory antigen despite the fact that the PHA-exposed lymphocytes were obtained from donors immunized with Salmonella and had reacted actively with E.coli. This differential antigenic recognition by PHA-induced lymphoblasts in bacterial adherence supports the theory that PHA, under the experimental conditions outlined, acts on cellular organelles which govern the permanency of immunity and reflects differences between the natural and acquired immune state.