title: Recirculation and homing of lymphocyte subsets: dual homing specificity of beta 7-integrin(high)-lymphocytes in nonobese diabetic mice.
abstract: The beta 7-integrin subunit can pair with two alpha-chains, alpha 4 and alpha E, and is expressed mainly on lymphocytes. As an alpha 4-heterodimer it binds to the mucosal addressin MAdCAM-1, thus acting as a mucosal homing receptor. As an alpha E-heterodimer it binds to E-cadherin and is mainly found on intestinal intraepithelial lymphocytes. Consequently, beta 7 is mostly expressed on lymphocytes of the mucosal immune system. To study the compartmentalization of these cells further we compared the distribution of such lymphocytes in two strains of mice (BALB/c and NOD) and found that the distribution of beta 7-positive lymphocytes among various lymphoid tissues in these strains was very different. In NOD mice a conspicuous population of beta 7-integrin(high) lymphocytes expressing either alpha 4, alpha E, or both, was found in nonmucosal lymphoid tissues such as peripheral lymph nodes (PLNs). They mostly expressed the PLN homing receptor L-selectin, and included both naive and memory cells on the basis of their expression of CD44/pgp-1 and CD45RB, as did the few beta 7(high) lymphocytes in BALB/c PLNs. Their homing to Peyer's patches (PPs) and PLNs was equally effective and the cells homing to PPs and PLNs were equal in their level of L-selectin and alpha 4/beta 7 expression. However, functional studies indicated that their homing to PPs mostly depended on alpha 4/beta 7-integrin, whereas they mainly used L-selectin to home to PLNs. beta 7(high) lymphocytes were found also in circulating blood of unmanipulated NOD mice, and their L-selectin expression was higher than in BALB/c mice. These results show that lymphocytes of the mucosal immune system may also express the peripheral node homing receptor L-selectin during their recirculation and that in NOD mice they frequently retain a dual homing specificity, which leads to their accumulation in nonmucosal tissues.
authors.affiliation: National Public Health Institute, Turku, Finland.
authors.forename: A
authors.initials: A
authors.lastname: Hänninen
authors.forename: M
authors.initials: M
authors.lastname: Salmi
authors.forename: O
authors.initials: O
authors.lastname: Simell
authors.forename: D
authors.initials: D
authors.lastname: Andrew
authors.forename: S
authors.initials: S
authors.lastname: Jalkanen
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000502:physiology; D015815:Cell Adhesion Molecules; D002465:Cell Movement; D018960:Hyaluronan Receptors / Q000032:analysis; D007136:Immunoglobulins / Q000502:physiology; D007156:Immunologic Memory; D039001:Integrin alpha Chains; D039441:Integrin alpha4; D039641:Integrin beta Chains; D016023:Integrins / Q000502:physiology*; D019041:L-Selectin / Q000502:physiology; D017493:Leukocyte Common Antigens / Q000032:analysis; D008198:Lymph Nodes / Q000166:cytology / Q000276:immunology; D016131:Lymphocyte Subsets / Q000737:chemistry / Q000166:cytology*; D008221:Lymphoid Tissue / Q000166:cytology / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D016688:Mice, Inbred NOD / Q000276:immunology*; D009088:Mucoproteins / Q000502:physiology; D009928:Organ Specificity; D010581:Peyer's Patches / Q000166:cytology / Q000276:immunology; D055503:Protein Multimerization; D016201:Receptors, Lymphocyte Homing / Q000502:physiology*
chemical_list: D015703:Antigens, CD; D015815:Cell Adhesion Molecules; D018960:Hyaluronan Receptors; D007136:Immunoglobulins; D039001:Integrin alpha Chains; D039641:Integrin beta Chains; D016023:Integrins; C489082:Madcam1 protein, mouse; D009088:Mucoproteins; D016201:Receptors, Lymphocyte Homing; C091367:alpha E integrins; C091368:integrin beta7; D019041:L-Selectin; D039441:Integrin alpha4; D017493:Leukocyte Common Antigens