Histologic analysis of T lymphocyte activation in reactive lymph nodes
Bogen, S.A.; Weinberg, D.S.; Abbas, A.K.
Journal of Immunology 147(5): 1537-1541
1991
ISSN/ISBN: 0022-1767 PMID: 1880415 Document Number: 373968
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 IL-2+ 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.