Plasma membranes from pig mesenteric lymph-node lymphocytes contain a large number of polypeptide chains ranging in molecular weight from 20,000 to greater than 470,000, with a major component of 46,000. There are approx. 12-15 glycoproteins. The membranes contain immunoglobulin G, which comprises 0.6% of the total protein. Immunoglobulin M is also detected, but has not been accurately quantified for technical reasons. Possible origins of the membrane-associated immunoglobulin are briefly discussed. It is concluded that the immunoglobulin is probably associated with the plasma membrane in the intact cell.
