A Modified Immunofluorescence Technique for Detection of Surface Ig 1

Abstract

It is conceivable that plasma cells secreting immmunoglobulins can have the same immunoglobulin on their cell surface which serves as receptor. Undoubtedly the surface receptor density is influenced by the cell cycle or stage of development (1, 2). The direct staining of receptors of plasma cells has been relatively unsuccessful. New and sensitive procedures have been developed for the detection of the surface receptors of lymphoid cells, indicating the presence of Ig receptors on the surface of such cells by immunofluorescence (3–5), and immunocyto-adherence of sensitized erythrocytes (6), or with radiolabeled antiimmunoglobulin antibodies (7). Recently, Pernis et al. (8) showed the presence of IgM receptors on the plasma cells of bone marrow of a case of Waldenstrom's macro-globulinemia. However, Paraskevas et al. (9) and Pernis et al. did not demonstrate the surface immunoglobulins in murine myeloma cells of the IgG class.

In this paper we report the experiments of staining of surface immunoglobulins of the plasma cell lines of the ascites tumors. We have utilized MOPC 104E which secretes an IgM antibody to bacterial dextran B-1355, MOPC 315 which secretes an IgA antibody to DNP, Adj Pc5 which secretes an IgG₂ and Ehrlich carcinoma. We also present the immunofluorescence evidence for the presence of IgG₂-like globulins on the surface of tumor cells of MOPC 104E.

Materials and Methods. Preparation of tumor cell suspension. Ascites tumors were collected from mice bearing MOPC 104E, MOPC 315, Adj Pc5, and Ehrlich carcinoma, centrifuged and the supernatant removed. The cells were washed four times with saline and kept at 0°.

Preparation of monospecific antisera. Preparation of mouse IgM. Purification of mouse IgM was accomplished since the IgM reacts with bacterial dextran B-1355. Sepharose 2B was washed with distilled water to remove sodium azide preservative and then with 0.1 M NaHCO₃, pH 11.0 and placed in an ice bath.