Wheat-germ agglutinin initiates monocytoid cell killing of non-antibody-coated erythrocytes.

Cells bearing alien surface antigens can be specifically destroyed by antibodies directed to the antigens and certain Fc receptor-bearing lymphoid or monocytoid cells through a killing mechanism known as antibody-dependent cellular cytotoxicity (ADCC). The present study was undertaken to see if lectins could substitute for specific antibody in ADCC and initiate lysis of non-antibody-coated erythrocytes. Human peripheral blood leucocytes and mouse PU-5 monocytoid cell lines were used as effector cells. Target-cell destruction was measured by the specific release of 51Cr. Our data indicated that Wheat-germ agglutinin (WGA), but not concanavalin A or soybean agglutinin, could activate killing of non-antibody-coated erythrocytes by human peripheral blood leucocytes and PU-5 cells. The membrane structure on the effector cell that was triggered by WGA directly related to N-acetyl-glucosamine and may be adjacent to, if not part of, the Fc receptor.