Heterogeneity of Sheep Small Lymphocyte Populations in RNA Labelling

Abstract

The labelling pattern of 3H-labelled uridine incorporation into RNA was studied by autoradiography in small lymphocytes obtained from the efferent lymph of normal sheep lymph nodes. Heavily labelled small lym-phocytes were always observed in the sheep lymphocyte population. They constituted 3.6 % of the total population. Antigen-stimulation did not alter the number of heavily labelled small lymphocytes. The majority of small lympho-cytes contained only one or two nucleoli, but 5 to 8 percent of the population possessed more than five nucleoli. The possibility was considered that the heterogeneity of small lymphocytes in RNA labelling may be associated with the development of nucleoli and that the heavily labelled small lymphocytes were engaged in particular functions being actively pursued in the efferent lymph.