Relative proportions of mitotic T and B cells in PHA-stimulated lymphocyte cultures.

Peripheral blood lymphocytes from six healthy adults were stimulated with phytohemagglutinin (PHA) and cultured for 3 days. The relative proportions of mitotic lymphocyte subsets were determined by a method that allows both cytogenetic and immunologic characterization of a mitotic cell. The results directly indicated that not only T cells but also B cells undergo mitosis in PHA-stimulated lymphocyte cultures. The frequency of the mitotic B cells varied between 6% and 20%.