immunoglobulin definition
Immunoglobulin. Definition. noun, plural: immunoglobulins. (1) Any of several classes of structurally related proteins in the blood serum, produced by plasma cells as an immune response against foreign agents (antigens).(2) The fraction of the blood serum containing antibodies.Supplement.oun, plural: immunoglobulins. (1) Any of several classes of structurally related proteins in the blood serum, produced by plasma cells as an immune response against foreign agents (antigens). (2) The fraction of the blood serum containing antibodies.