Immunoglobulins on the surface of lymphocytes. I. Distribution and quantitation

The distribution, and quantity of immunoglobulins on the surface of lymphocytes has been studied by means of immunofluorescence and a quantitative radio-immunoassay. Surface immunoglobulins were found on approximately 45% of spleen and marrow lymphocytes and 7-14% of lymphocytes from lymph nodes, peripheral blood, and peritoneal exudate. Thymic lymphocytes contained undetectable amounts of immunoglobulin. In the spleen the different immunoglobulins were present in the following order: gammaG2 > gammaG1 > M > gammaA > gammaG3. The surface immunoglobulin was largely removable by brief treatment with trypsin. Quantitative analysis indicated that 50,000-150,000 molecules of immunoglobulin were present on an individual cell. A variety of observations make it likely that this lymphocyte-associated immunoglobulin. is a product of the cell to which it is attached rather than a form of cytophilic antibody.