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The distribution, immune complex trapping ability and morphology of
follicular dendritic cells in popliteal lymph nodes of aged rats
H. Sato1 and M. Dobashi2
1Department of Forensic Medicine, National Defense Medical
College, Tokorozawa and 2Department of Pathology, Yamagata University School
of Medicine, Yamagata, Japan
Offprint requests to: Dr. Hironobu
Sato, M.D., Department of Forensic Medicine, National Defense Medical College,
3-2, Namiki, Tokorozawa, Saitama, 359, Japan
Summary. Immune system function
declines with age, and lymph nodes involute. The aims of the study were
to describe the distribution of follicular dendritic cells (FDCs) in the
lymphoid follicles of aged rats, and to determine whether these cells have
reduced ability to trap immune complexes (ICs). Popliteal lymph nodes of
rats aged 24-28 months were immunostained for S-100 protein as a marker
of FDCs. Some rats were pretreated with peroxidase-anti-peroxidase complex
(PAP) as an IC. FDCs were densely distributed in lymphoid follicles, which
contained many primary follicles and a few secondary follicles. FDCs in
primary follicles stained weakly for S-100 protein, and showed weak trapping,
while those in secondary follicles stained strongly for both S-100 protein
and trapping. Ultrastructurally, in involuted lymphoid follicles FDCs were
atrophic. We conclude that FDCs in aged rats are densely distributed in
involuted follicles and show reduced trapping ability and atrophic morphology.
This seems to reflect the long life of FDCs and the reduced numbers of lymphoid
cells in these follicles. We suggest that FDCs in aged rats may show some
of their normal functions if fully developed germinal centers are induced,
and may not play an important role in the process of involution of the follicles.
Histol Histopathol 13, 99-108 (1998)
Key words: Follicular dendritic
cells, Aging, Nerve tissue protein S100, Antigen-antibody complex
DOI: 10.14670/HH-13.99
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