H3‐leucine incorporation in antigenically stimulated rat popliteal lymph node cells

Abstract

AbstractThe effect of antigenic stimulation with pertussis and sheep red blood cell antigens was studied in the rat popliteal lymph nodes. H3‐leucine was used to assess protein metabolism in the various cell types of the reactive lymph nodes following both primary and secondary stimulation with these antigens. Radioautographs of tissue smears were used to make quantitative and qualitative assessments of the extent of intracellular protein synthesis. In addition, changes in the cellular populations of various lymphoid cell lines were determined utilizing differential cell counts and total cells present in the reacting nodes. These data were used principally to assess the role of the lymphocytic cells in the ontogeny of the immune response.Large and medium lymphocytes responded to antigenic stimuli by increasing intracellular protein synthesis. This newly synthesized protein most likely reflected the requirements of large and medium lymphocytes for growth, division and the production of immunoglobulins. The small lymphocytes, as a group, showed only minimal changes in intracellular protein synthesis following antigenic stimulation.The responses by large and medium lymphocytes and plasma cells were qualitatively similar following primary and secondary stimuli. The differences in these responses appeared to be reflected by the number of cells involved and by the temporal sequence in which the cells appeared.