title: Histologic analysis of T lymphocyte activation in reactive lymph nodes.
abstract: As an approach to defining the anatomic sites of T cell activation in situ, we have developed an immunocytochemical stain for IL-2, a T cell-derived cytokine synthesized shortly after Ag-induced activation. Analysis of lymph nodes from mice immunized with keyhole limpet hemocyanin emulsified in CFA demonstrates that the IL2+ cells appear in a perivascular location 4 days after antigenic challenge. After germinal centers develop, IL-2+ cells are situated in a parafollicular pattern. Serial sections stained for different types of APC, including B cells, interdigitating dendritic cells, and macrophages, demonstrate a close physical association between IL-2+ cells and macrophages. These findings may have important implications for defining how APC bearing processed Ag and Ag-specific T cells interact in the complex environment of lymphoid tissues.
authors.affiliation: Department of Pathology, Brigham and Women's Hospital, Boston, MA 02115.
authors.forename: S A
authors.initials: SA
authors.lastname: Bogen
authors.forename: D S
authors.initials: DS
authors.lastname: Weinberg
authors.forename: A K
authors.initials: AK
authors.lastname: Abbas
mesh_terms: D000818:Animals; D000938:Antigen-Presenting Cells / Q000502:physiology; D005260:Female; D007150:Immunohistochemistry; D007376:Interleukin-2 / Q000032:analysis / Q000235:genetics / Q000494:pharmacology; D008198:Lymph Nodes / Q000276:immunology*; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D012333:RNA, Messenger / Q000032:analysis; D011994:Recombinant Proteins / Q000494:pharmacology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D007376:Interleukin-2; D012333:RNA, Messenger; D011994:Recombinant Proteins