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Development of immune complex trapping: experimental study of lymphoid
follicles and germinal centers newly induced by exogenous stimulants in
mouse popliteal lymph nodes
K. Horie1, D. Chen2 and H. Hoshi1
1Department of Anatomy, Nihon University School of Medicine,
Tokyo, Japan and 2Department of Histology and Embryology, Norman Bethune
University of Medical Sciences, Changchun, China
Offprint requests to: Dr. Hajime
Hoshi, Department of Anatomy, Nihon University School of Medicine, Ohyaguchi,
Itabashi-ku, Tokyo 173, Japan
Summary. The development of
immune complex trapping in newly-induced lymphoid follicles of draining
popliteal lymph nodes was investigated in young adult mice, which had been
given bilateral injection of hemocyanin (KLH) or phytohemagglutinin (PHA),
each absorbed onto alumina. HRP-anti-HRP immune complex was injected into
the footpad 1 day before sacrifice. Using three series of semi-serial cryostat
sections prepared from each popliteal node, the number of lymphoid follicles
in each node was counted, and follicular localization of the in vivo injected
and in vitro applied immune complexes in each follicle was determined. By
day 5, a large germinal center had developed within each preexisting follicle.
A large number of 'new' secondary follicles, each containing a small PNA-positive
germinal center, appeared outside pre-existing follicles, from day 5 through
day 11 in KLH-treated nodes, and from day 7 through day 14 in PHA-treated
nodes. Shortly after their appearance, new secondary follicles showed no
in vitro or in vivo trapping, but subsequently, many of the new follicles
began to display in vitro trapping, at first weakly but later intensely.
Occurrence of in vivo trapping in new follicles took some time and was first
recognized when new follicles showed intense in vitro trapping. At day 21
or 25, many of the new follicles showed both in vitro and in vivo trapping.
It was concluded that in lymph nodes treated with a stimulant, secondary
follicles containing germinal centers can be formed de novo in the extrafollicular
zone where the follicular trapping microenvironment is absent, but subsequently
the micro-environment capable of trapping immune complexes develops at the
site of formation of new follicles. Histol. Histopathol. 14, 11-21 (1999)
Key words: Immune complex trapping,
Lymphoid follicle, Germinal center, Lymph node, Mouse
DOI: 10.14670/HH-14.11
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