Immobilization of lymphocytes at surfaces by lectins

Phytohemagglutinin (PHA) and Concanavalin A (ConA) cause normal chicken lymphocytes to adhere to glass and plastic surfaces. Pokeweed mitogen (PWM) does not cause adherence. The effect of ConA was studied in detail. The reaction begins within 15 min at 25 °C and proceeds to completion by 2 h. It is independent of pH and resembles in this respect the spontaneous adherence which can occur in protein-depleted suspensions of chicken lymphocytes. It is distinguished from spontaneous adherence by conducting the reaction in 1% or more serum protein; high concentrations exert a slight restraint, which can be overcome by increasing the concentration of ConA. The reaction is slightly greater at high cell concentrations, is inhibited by 3 mM sodium cyanide, and is effectively blocked by 3 mM iodoacetamide and the α-methyl--glycosides of glucose and mannose. The reaction is not affected by 2-deoxy--glucose or N-acetyl glucosamine. Adherent lymphocytes detach when the lectin solution is replaced with lectin-free saline; they readhere when reexposed to ConA or to alloantibody directed against lymphocyte surface antigen. At low concentrations of ConA the large lymphocytes of the bursa of Fabricius adhere more rapidly than the small lymphocytes of the blood and thymus. Mouse lymph node lymphocytes adhere in the same manner as small chicken lymphocytes.