Immunologic memory of phytohemagglutinin-stimulated lymphocytes.

By JEROME I. BRODY AND HENRY D. SOLTYS T HE PUBPOSE of this study was to delineate the durability and persistence of immunologic recall in the normal peripheral blood lymphocyte using methods which might reflect the importance of the manner by which imniunologic information is acquired. This was done in the present investigation with the technic of bacterial adherence,”2 in which circumferential adhesion of a microorganism to the lymphocyte surface indicates antibody production by this cell. The assays described below compared the immune reactivity of phytohemagglutinin-stimulated lymphocytes against E. coli, a natural, lifelong immunogen, ’4 and against Salmonella, one which is acquired and deliberately given when a special need arises. Although phytohemagglutinin (PHA) is considered a general biosynthetic and metabolic stimulant of lymphocytes, it is also able, under appropriate circumstances, to exercise its biologic activity on a more specific, genetic level. This occurs, for example, when it predictably alters the proportions of genetically controlled forms of lymphocyte lactate and malate dehydrogenases.5 Theoretically, on an analogous basis, it could potentially influence lymphocyte immune responses toward various antigens depending on their type, the ii eans by which cellular contact was initiated, and on the immunologic memory ultimately generated and stored within this cell.