The intracellular localisation of immunoglobulin in human lymphoid cells and haematopoietic cell lines by immunoperoxidase electron microscopy.

A technique is described for the ultrastructural localisation of intracellular immunoglobulin (Ig) in human lymphoid cell suspensions by the immunoperoxidase method. The technique involves restricted saponin digestion of glutaraldehyde prefixed cells to enhance conjugate penetration. With this method of staining Ig was located in the rough endoplasmic reticulum, perinuclear space and Golgi apparatus in human lymphoid cells from a variety of sources, which is consistent with previously published observations using other ultrastructural techniques. In contrast, diffuse intracytoplasmic staining was predominant in cells prefixed with glutaraldehyde but not treated with saponin. These differences in patterns are discussed in terms of membrane permeability. Although saponin treatment was necessary for consistent localisation of intracellular Ig it resulted in unavoidable loss of Ig from the surface of the cells.