title: Clustering of adhesion receptors following exposure of insect blood cells to foreign surfaces.
abstract: Cell-mediated immune responses of insects involve interactions of two main classes of blood cells (hemocytes) known as granular cells and plasmatocytes. In response to a foreign surface, these hemocytes suddenly transform from circulating, non-adherent cells to cells that interact and adhere to each other and the foreign surface. This report presents evidence that during this adhesive transformation the extracellular matrix (ECM) proteins lacunin and a ligand for peanut agglutinin (PNA) lectin are released by granular cells and bind to surfaces of both granular cells and plasmatocytes. ECM protein co-localizes on cell surfaces with the adhesive receptors integrin and neuroglian, a member of the immunoglobulin superfamily. The ECM protein(s) secreted by granular cells are hypothesized to interact with adhesion receptors such as neuroglian and integrin by cross linking and clustering them on hemocyte surfaces. This clustering of receptors is known to enhance the adhesiveness (avidity) of interacting mammalian immune cells. The formation of ring-shaped clusters of these adhesion receptors on surfaces of insect immune cells represents an evolutionary antecedent of the mammalian immunological synapse.
authors.affiliation: Department of Entomology, University of Illinois, 320 Morrill Hall, 505 S. Goodwin Avenue, Urbana, IL 61801, USA. j-nardi@uiuc.edu
authors.forename: James B
authors.initials: JB
authors.lastname: Nardi
authors.forename: Shufei
authors.initials: S
authors.lastname: Zhuang
authors.forename: Barbara
authors.initials: B
authors.lastname: Pilas
authors.forename: Charles Mark
authors.initials: CM
authors.lastname: Bee
authors.forename: Michael R
authors.initials: MR
authors.lastname: Kanost
mesh_terms: D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D016326:Extracellular Matrix Proteins / Q000502:physiology; D006434:Hemocytes / Q000502:physiology*; D007814:Larva / Q000502:physiology; D018402:Manduca / Q000502:physiology*; D008562:Membrane Glycoproteins; D021962:Membrane Microdomains / Q000502:physiology; D008565:Membrane Proteins / Q000502:physiology*; D019038:Platelet Glycoprotein GPIb-IX Complex
chemical_list: D016326:Extracellular Matrix Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D019038:Platelet Glycoprotein GPIb-IX Complex; C094990:adhesion receptor