Morphological interactions of interdigitating dendritic cells with B and T cells in human mesenteric lymph nodes.
Interdigitating dendritic cells (IDC) of the human mesenteric lymph nodes (LN) were examined by two-color immunofluorescent microscopy and flow cytometry to clarify their exact localization, immunophenotype, and relationships with T and B cells. IDC were identified as HLA-DR(bright) large dendriform cells of the T cell areas co-expressing CD40, CD54 (ICAM-1), CD80 (B7/B7-1), CD83, and CD86 (B70/B7-2). The majority of IDC directly attached to a few IgD+ naive B cells as well as to numerous CD4+ T cells. When LN cells were singly suspended and briefly incubated in vitro, IDC formed clusters with IgD+ IgM+ naive B cells, but not with IgA+ or IgG+ B cells. When suspended LN cells were cultured, clustered B cells disappeared within 7 days, and on prolonged culture, some IDC developed into extensively dendriform cells forming stable complexes with several or sometimes numerous CD4+ IL-2R+ CD40L+ activated T cells. These findings indicate that resting naive B cells actually interact with IDC directly in T cell areas of human secondary lymphoid tissues. IDC have a non-antigen (Ag)-specific, strong affinity for resting naive B cells, but this affinity is transient and IDC cannot form stable complexes with B cells, although they can form stable complexes with activated T cells. It is suggested that the stable IDC/Ag-activated T cell complexes make it possible to capture and to stimulate rare Ag-specific resting naive B cells with high efficiency.
Takahashi
K
K
Faculty of Health Science, the Department of Dermatology, and the Department of Pathology, Okayama University Medical School, Okayama, Japan. dend@cc.okayama-u.ac.jp
Kenji
A
A
Norihiro
T
T
Eisaku
K
K
Takashi
O
O
Kazuhiko
H
H
Tadashi
Y
Y
Tadaatsu
A
A
D000368:Aged; D001402:B-Lymphocytes / Q000502:physiology*; D002449:Cell Aggregation; D002450:Cell Communication; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000502:physiology*; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006801:Humans; D008198:Lymph Nodes / Q000166:cytology*; D008643:Mesentery; D008875:Middle Aged; D013601:T-Lymphocytes / Q000502:physiology*; D013997:Time Factors