title: Inhibition of the mobility of mouse lymphocyte surface immunoglobulins by locally bound concanavalin A.
abstract: Fluorescence photobleaching recovery was used to study directly and quantitatively the inhibition of the lateral mobility of surface immunoglobulins (sIg) on mouse lymphocytes by localized binding of concanavalin A (Con A) coupled to platelets. Up to a threshold occupancy of about 10% of the upper cell surface by Con A-platelets, the diffusion coefficient and mobile fraction of sIg remained as in untreated cells (5.3 X 10(-10) cm2/sec and 0.65, respectively). At higher surface occupancy, these values decreased to 8 X 10(-11) cm2/sec and 0.11. The magnitude of the effect was independent of the percentage occupancy above the threshold and of the distance from the bound Con A-platelets, indicating a cooperative and propagated phenomenon. Treatment with colchicine or cytochalasin B separately induced only partial reversal of the Con A-induced modulation. Treatment with both reversal of the Con A-induced modulation. Treatment with both drugs together was synergistic and fully reversed the mobility inhibition. The modulation was unaffected by NaN3 and 2-deoxyglucose, suggesting no dependence on metabolic energy. Con A-platelets did not affect the mobility of a lipid probe. Models for the Con A-induced modulation and the relationship between the effects of Con A on sIg mobility and patch formation are discussed.
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000502:physiology; D003208:Concanavalin A; D004058:Diffusion; D007136:Immunoglobulins; D008214:Lymphocytes / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D013050:Spectrometry, Fluorescence
chemical_list: D007136:Immunoglobulins; D003208:Concanavalin A