Characterization of the Lymphocyte Surface Receptors for Con A and PHA

Human peripheral blood lymphocytes were iodinated by the lactoperoxidase technique, and the surface receptors for the mitogens concanavalin A (Con A) and phytohemagglutinin (PHA) were analyzed by solubilizing the membrane protein and incubating with mitogen and antimitigen antibody. The resulting precipitates were washed and analyzed by gel electrophoresis. Con A was to bind to about twice as much labeled protein as PHA. Sodium dodecyl sulfate gels showed that multiple surface membrane proteins bind to these mitogens and that the pattern of peaks of Con A receptors in generally similar to the pattern of PHA receptors. Long-term lymphoid tissue culture cells lines also show multiple receptor peaks for mitogens, indicating that the heterogeneity of receptors is not caused entirely by lymphocyte heterogeneity.