The in vivo induction of mouse lymphocyte transformation by phytohemagglutinin

Abstract

Summary The effects of the intravenous administration of phytohemagglutinin-M (PHA-M) and phytohemagglutinin-P (PHA-P) on the mesenteric lymph node, spleen, bone marrow, thymus and peripheral blood of the mouse have been studied. Qualitative changes similar to that observed when PHA is used in vitro with lymphocytes were found. There was a marked shift in the differential of the mesenteric node and peripheral blood from small lymphocytes to medium and large lymphocytes, many of which resemble the blast-like cells seen in tissue culture. Both the shift in differential and the increase in proportion of large and medium cells in deoxyribonucleic acid synthesis in the mesenteric node were maximal at 3 days after the administration of PHA. An increase in the weight of the spleen and the proportion of cells in mitosis and in DNA synthesis was also maximum at 3 days, whereas in the bone marrow the maximum effect occurred only 1 day after PHA. No increase in weight of the thymus, shift in the differential or increase in the proportion of cells in DNA synthesis or mitosis was found with PHA-M, but PHA-P did have a slight effect on all three of these parameters. As a result of its erythro- and leukoagglutinating properties, PHA-M caused a decreased hematocrit, red blood cell count and peripheral platelet count with a compensatory increase in the absolute number of megakaryocytes of the bone marrow 3 days after its administration.