The ultrastructural localization of immunoglobulins in human b cells of immunoproliferative diseases.

The cellular distribution of immunoglobulins in human malignant and normal B cells was investigated by immunoelectron microscopy by direct incubation of fixed cells with electron microscopy by direct incubation of fixed cells with peroxidase-coupled antibody. These conjugates penetrated into the cell, resulting in the simultaneous detection of surface and cytoplasmic immunoglobulins. The latter were seen as specific intracisternal staining of the perinuclear space and endoplasmic reticulum and occasionally of the Golgi complex. Plasma cells were frequently characterized by a heterogeneity of reactivity of the endoplasmic reticulum. Minute amounts of cytoplasmic immunoglobulin were demonstrated in cells without developed secretory organelles, such as lymphoma cells and lymphocytes from chronic lymphocytic leukemia (CLL). The method allowed us to define several subsets of cells according to the expression of surface and cytoplasmic immunoglobulins and thus to determine the stage of maturation of cells involved in monoclonal proliferation.