Browsing by Subject "Follicular dendritic cells"

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    A change in the localization of the region trapping immune complexes in rat popliteal lymph nodes during development of germinal centers, with regard to the distribution of follicular dendritic cells
    (Murcia : F. Hernández, 1996) Sato, H.; Dobashi, Michio; Maeda, K.
    A study was conducted to clarify changes in the relationship between the region of irnrnune complex (IC) trapping by follicular dendritic cells (FDCs) and the distribution of FDC during reaction of germinal centers (GCs), and to examine the relationship between the tridiniensional shape of the IC-trapping regions and their two-dimensional shape. Five-week-old rats were given footpad injections of sheep red blood cells, and then their popliteal lymph nodes were excised between days O and 42, 24 h after injection of peroxidase-antiperoxidase complex (PAP) as an IC. The specimens were immunostained for PAP trapping on serial paraffin sections, and for S-100 protein as a marker of FDCs. It was found that during the GC reaction, PAP trapping became weak and then disappeared on the basal side of developing GCs where S-100 protein-positive FDCs were still present. Al1 of the 1933 lymph follicles examined were found to trap PAP. Whereas the tridiniensional shapes of the trapping regions showed similar pattems according to the development of lymph follicles, their two-dimensional shapes varied. We suggest that FDCs in primary follicles may differentiate into FDCs in the light zone and FDCs in the dark zone in secondary follicles. To evaluate each of the compartments of a lymph follicle more accurately, investigators should pay attention to the tridimensional shape of the compartment.
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    Ontogeny of the antigen-reactive lymph follicle-forming capacity of the popliteal lymph node in neonatal mice
    (Murcia : F. Hernández, 2005) Hiramoto, M.; Aizawa, S.; Horie, K.; Nagata, H.; Hoshi, H.
    The ontogenetic development of the reactive lymph follicle-forming capacity of the popliteal lymph node was investigated immunohistochemically in young mice which had received a single injection of hemocyanin (KLH) in a rear footpad at a predetermined age (between 1 and 21 days). The mice were sacrificed at various intervals after injection. In non-stimulated young mice, primary lymph follicles first appeared in the popliteal node at 11 days of age. When KLH was given to 7-day-old or older mice, each draining popliteal node showed a marked increase in B lymphocytes in the extrafollicular zone 3 days after injection and produced a number of ‘new’ lymph follicles outside the pre-existing follicles over the next few days. In mice injected at 2-4 days of age, these nodes showed an increase in B lymphocytes in the outer cortex and had produced several lymph follicles by 8 days of age. The number of lymph follicles produced by each node tended to increase in line with age at injection. These results indicate that neonatal popliteal nodes become able to produce lymph follicles in response to exogenous antigens some time before ontogenetically developing follicles appear. The formation of new lymph follicles observed in draining popliteal nodes after KLH injection at an early postnatal age is discussed in relation to the ontogenetic development of stromal cells (precursors of follicular dendritic cells) that are capable of interacting with B lymphocytes and the extent of B lymphocyte influx into the node induced by KLH stimulation.
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    The density and distribution of follicular dendritic cells in rat popliteal lyrnph nodes: a decrease in their density and a change in their distribution after stirnulation
    (Murcia : F. Hernández, 1995) Sato, H.; Dobashi, Michio
    To determine whether follicular dendritic cells (FDCs) increase after stimulation, and also to confirm the widely accepted finding that the density of FDCs in the light zone is higher than that in the dark zone, we examined the density of FDCs in lymph follicles of rat popliteal lymph nodes. Rats aged five weeks were stimulated by injection of sheep erythrocytes, and then examined 10 days later. Unstimulated rats were also examined. After embedding in paraffin, the removed lymph nodes were immunostained with anti-S-100 protein antibody as a marker of rat FDCs. The density of FDCs was determined by measuring the area of the lymph follicle and counting the number of S-100 protein-positive cells within it. The density of FDCs in the lymph follicles of stimulated rats was found to be significantly lower than in 5-week-old and unstimulated rats. The density of FDCs in the light zone was similar to that in the dark zone when germinal center bordering cells (GCBCs), distributed at the border between the dark zone and the adjacent corona, were counted as FDCs. We conclude that the density of FDCs in lymph follicles decreases after stimulation, and suggest that FDCs have no or only very slight proliferative activity under normal conditions. Investigators may need to consider GCBCs in order to understand how FDCs differentiate.
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    The distribution, immune complex trapping ability and morphology of follicular dendritic cells in popliteal lymph nodes of aged rats
    (Murcia : F. Hernández, 1998) Sato, H.; Dobashi, Michio
    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 1C. 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.