Surface immunoglobulin of human lymphocytes.

Using ferritin as surface marker, the localization of the surface immunoglobulin (Ig) was studied on peripheral lymphocytes from normal human individuals and patients with macroglobulinaemia Waldenström by scanning immunoelectron microscopy. Normal IgG-, IgM-lymphocytes and pathological IgM-lymphocytes were then compared with regard to their topographical differences. In all cells examined, IgG- and IgM-conjugated ferritin particles were detected all over the cell surface, but the distribution of the former on the normal IgG-lymphocytes was slightly more diffuse than that of the latter on the normal and pathological IgM-lymphocytes. Furthermore, in the pathological IgM-lymphocytes, the clustered IgM-conjugated ferritin particles were found in great number on the microvilli. Normal IgG-lymphocytes were almost always characterized by short rod-like microvilli standing densely and vertically on the cell surface. Some of normal IgM-lymphocytes had a similar appearance to those of normal IgG-lymphocytes (type A) but others (type B) had tilted rod-like microvilli or wide plate-like processes on their surface. As for IgM-lymphocytes of macroglobulinaemia, most lymphocytes had tilted rodlike mirovilli and wide plate-like processes similar to type B, whereas a minor population of the pathological lymphocytes carried long, thin rod-like microvilli standing vertically on the surface.