Individual rabbit peripheral blood lymphocytes reactive to anti-immunoglobulin and phytohemagglutinin or Concanavalin A identified by immunoelectronmicroscopic demonstration of endocytosis.

Individual rabbit lymphocytes reactive to phytohemagglutinin or Concanavalin A, and bearing membrane-associated surface immunoglobulin have been identified by electron microscopy. Endocytosis of lectin-lectin receptor complexes, which has previously been shown to be a marker for subsequent lectin-induced blast transformation was used as a marker for lectin reactivity. Surface immunoglobulin was detected by modified mixed antiglobulin (Coombs) technique. Lectin-reactive, sIg-bearing cells are well represented among lymphocytes from peripheral blood. Few of these cells, however, are found among lymphocytes isolated from spleen or popliteal lymph node. From these results it is suggested that some rabbit lymphocytes from peripheral blood share T cell (lectin reactivity) and B cell (bearing sIg) properties, or that reactivity to Con A is not an exclusive T cell property and sIg is not an exclusive property of B cells.