title: Epithelial cell-specific laminin 5 is required for survival of early thymocytes.
abstract: The gene LamC2 encoding the gamma2 chain of laminin 5, an epithelial cell-specific extracellular matrix protein, was identified in a PCR-based subtracted cDNA library from mouse thymic stromal cells. The mRNA existed in two alternative forms (5.1 and 2.4 kb). The full-length message was highly expressed in SCID thymus and in a nurse cell line, but not in other thymic epithelial cell lines, while the short form was more widely expressed. In situ hybridization and immunohistochemical staining revealed laminin 5 expression mostly in the subcapsular region of the adult thymus. Addition to fetal thymic organ cultures of a cell adhesion-blocking mAb to the alpha3 chain of laminin 5 interrupted T cell development. There was a 40% reduction in the total yield of thymocytes, and the most profound decrease (75-90%) was seen in the CD25+CD44+ and CD25+CD44-subsets of the CD4-CD8- double negative fraction. Most of the surviving double negative thymocytes expressed Sca-1, and there were significant increases in the number of cells with CD69 expression and in the fraction of annexin V-stained cells. None of these changes were observed with a nonblocking anti-laminin alpha3 chain mAb. These results suggest that the interaction between double negative thymoctyes and laminin 5 made by subcapsular epithelial cells is required for the survival and differentiation of mouse thymocytes.
authors.affiliation: National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA. mkim@plaza1.snu.ac.kr
authors.forename: M G
authors.initials: MG
authors.lastname: Kim
authors.forename: G
authors.initials: G
authors.lastname: Lee
authors.forename: S K
authors.initials: SK
authors.lastname: Lee
authors.forename: M
authors.initials: M
authors.lastname: Lolkema
authors.forename: J
authors.initials: J
authors.lastname: Yim
authors.forename: S H
authors.initials: SH
authors.lastname: Hong
authors.forename: R H
authors.initials: RH
authors.lastname: Schwartz
mesh_terms: D000818:Animals; D019138:Antibodies, Blocking / Q000494:pharmacology; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D016923:Cell Death / Q000276:immunology; D002454:Cell Differentiation / Q000276:immunology; D019070:Cell Lineage / Q000276:immunology; D002470:Cell Survival / Q000276:immunology; D002478:Cells, Cultured; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000302:isolation & purification; D004847:Epithelial Cells / Q000276:immunology / Q000502:physiology*; D015723:Gene Library; D006131:Growth Inhibitors / Q000502:physiology; D016130:Immunophenotyping; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D016513:Mice, SCID; D009924:Organ Culture Techniques; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000037:antagonists & inhibitors / Q000502:physiology; D017154:Stromal Cells / Q000276:immunology / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology* / Q000276:immunology*; D013950:Thymus Gland / Q000033:anatomy & histology / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D000097794:Kalinin
chemical_list: D019138:Antibodies, Blocking; D000911:Antibodies, Monoclonal; D015815:Cell Adhesion Molecules; D018076:DNA, Complementary; D006131:Growth Inhibitors; D016693:Receptors, Antigen, T-Cell, alpha-beta; D000097794:Kalinin