The fine surface and internal structure of normal and disordered lymphocytes

A method has been developed to investigate the surface morphology oflymphoid cell suspensions using the scanning electron microscope. Normal human peripheral blood lymphocytes were found to be uniformly villous, with the number of microvilli per cell dependent on the cell surface area. A number of preparation techniques were found to affect adversely this surface morphology resulting in the loss of microvilli. Such preparative artefacts are discussed in the light of previously published work, which had suggested that T - lymphocytes are smoother than B - lymphocytes ( Polliack et al ., 1973 ). The similarity in the surface morphology of T - and B - lymphocytes was confirmed using rosetted lymphocytes, enriched cell populations and cells isolated from various lymphoid tissues.The surface morphology and ultrastructure of circulating abnormal cells from CLL, ALL, leukaemic reticuloendotheliosis, cutaneous T - cell lymphomas and paraproteinaemias, and of the lymphoma cells isolated from several histological types of lymphoma have been compared to their normal counterparts. In general, it was found that the surface morphology was related to the state of differentiation, rather than T - or B - origin. Attempts to confirm this were made by investigating the surface morphology of in vivo antigen and in vitro mitogen stimulated lymphocytes and cord blood lymphocytes. Various aspects of the structure of lymphocyte microvilli were investigated, including the ultrastructure, by several microscopic techniques and the location of certain cell surface receptors. These results are discussed relative to the possible function of microvilli in lymphocyte communication and recognition.