title: Lectin-induced modulation of snail hemocyte surface determinants: clearance of Con A-receptor complexes.
abstract: The fate of surface concanavalin A (Con A)-receptor complexes on hemocytes from two stocks of the snail, Biomphalaria glabrata (PR albino and 10-R2), was studied using both direct (Con A-FITC) and indirect (biotin-Con A, avidin-FITC) fluorescent staining methods. The results of experiments in which living hemocytes were exposed first to biotin-Con A, followed by fixation and subsequent treatment with avidin-FITC to localized surface-bound lectin, demonstrate that Con A complexes are rapidly cleared from hemocyte plasma membranes. Experiments employing Con A-FITC further indicate that clearance is accomplished through an internalization process whereby Con A-complexes are endocytosed and eventually accumulate as a single intracellular aggregate of fluorescent material in the cell body of each hemocyte. In addition, a redistribution of surface complexes into patches and caps is concomitant with receptor clearance, with a maximum frequency of patching (approx. 45%) and capping (approx. 30%) occurring within 5 and 10 min., respectively, of initial Con A exposure. PR albino and 10-R2 snail hemocytes appear indistinguishable with regards to their responsiveness to Con A-binding. The close similarity in the behavior of Con A complexes or circulating hemocytes from both snail stocks further support the conclusion that Con A-reactive determinants and their associated membrane components probably represent identical molecular populations on PR albino and 10-R2 B. glabrata blood cells.
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001667:Binding, Competitive; D001700:Biomphalaria / Q000276:immunology*; D001773:Blood Cells / Q000378:metabolism*; D002462:Cell Membrane / Q000276:immunology / Q000378:metabolism; D000939:Epitopes; D005455:Fluorescent Antibody Technique; D006434:Hemocytes / Q000276:immunology / Q000378:metabolism*; D011952:Receptors, Concanavalin A / Q000032:analysis*; D013696:Temperature
chemical_list: D000939:Epitopes; D011952:Receptors, Concanavalin A