title: Integrins and L-selectin in lymphocyte-endothelium interactions and homing into gut-associated tissue.
abstract: The selective entry of subpopulations and distinct differentiation stages of lymphocytes into different tissues is thought to be mediated by interaction of endothelial ligands with adhesion molecules on lymphocytes. L-selectin has been considered as a peripheral lymph node-specific homing receptor and alpha 4-integrins have been supposed to mediate entry into mucosa-associated lymphoid tissue. In vivo homing studies show that the specificity is not so clear-cut. The MEL-14 antibody indeed blocks almost completely lymphocyte homing into peripheral lymph nodes. However, entry into Peyer's patches and even the intestine itself is also affected. Thus, L-selectin plays a broader part as previously thought. Some antibodies against the alpha 4 and beta 1-integrin chain inhibit selectively lymphocyte homing to Peyer's patches by 50-70%. alpha 4-integrins therefore seem to be important for homing into mucosa-associated tissue, although a considerable fraction of cells does not require this molecule (or this epitope) for recognition of Peyer's patch endothelium. In vitro and in vivo data indicate that neither VCAM-1 nor fibronectin play a role for homing into Peyer's patches; most likely a further ligand recognized by distinct epitopes of alpha 4 is used for recognition of Peyer's patch HEV. A combination of the mAbs MEL-14 and PS/2.3 blocks nearly completely the localization in Peyer's patches. Beside alpha 4-integrins, the beta 2-integrin LFA-1 has been shown to be involved in lymphocyte recirculation. Also combinations of antibodies against LFA-1 and L-selectin as well as of anti LFA-1 with anti alpha 4 show synergistic effects.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Abteilung für Immunologie, Medizinische Klinik, Universitätskrankenhaus Eppendorf, Hamburg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Hamann
authors.forename: D
authors.initials: D
authors.lastname: Jablonski-Westrich
mesh_terms: D000818:Animals; D015815:Cell Adhesion Molecules / Q000502:physiology*; D004727:Endothelium / Q000502:physiology*; D004730:Endothelium, Vascular / Q000502:physiology*; D006801:Humans; D007249:Inflammation; D016023:Integrins / Q000502:physiology*; D007413:Intestinal Mucosa / Q000502:physiology*; D019041:L-Selectin; D008214:Lymphocytes / Q000502:physiology*; D010581:Peyer's Patches / Q000502:physiology*; D016201:Receptors, Lymphocyte Homing / Q000502:physiology*
chemical_list: D015815:Cell Adhesion Molecules; D016023:Integrins; D016201:Receptors, Lymphocyte Homing; D019041:L-Selectin