AN OBSERVATION OF EXPRESSION OF Ia-ANTIGEN ON CELLS IN SUSPENSION FROM UNSTIMULATED RAT SPLEENS / 解剖学报

Expression of Ia-antigen on cells in lymphoid dendritic cells (LDCs)-enrt- ched fractions isolated from unstimulated rat spleens was observed with ABC immunoperoxidase and indirect immunofluorescent staining methods. The results appeared that there were three types of cells in stained preparaions: 1. Large cells with dendritic processes on their surfaces showed dark brown in colour with ABC staining method and emitted intense light-green fluorescence with immuno- fluorescent staining technic. 2. Large rounded or ovoid cells without obviously ramifications revealed colourless or light yellow-brown in colour with ABC sta- ining method and emitted no or weak yellow-green fluorescence with immuno- fluorescent staining technic. 3. Spherical lymphocytes of varying in size were similar to type 2 cells in immunoreactivity. The results of SEM and S-100 pro- tein staining confirmed that these three types of cells were LDCs, macrophages and lymphocytes in turn. It is indicated that LDCs consistently expressed Ia- antigen in large amount on their surfaces.

COMPARATIVE OBSERVATION ON PHAGOCYTIC CAPACITIES OF DENDRITIC CELLS AND MACROPHAGES IN RAT SPLEEN / 解剖学报

Phagocytic capacities of both dendritic cells (DC) and macrophages(M?) in the DC-enriched fractions isolated from rat spleen were comparatively observed under electron microscope. Experiments were divided into two groups: in vitro and in vivo. In group 1, candida albicans(CA), cock red blood cells (CRBC) and CRBC opsonized with rat antiserum against CRBC (OCRBC) used as phagocytic markers were incubated with the DC-enriched fractions for 1h at 37℃ separately in vitro. In group 2, colloidal carbon (CC) (india ink) and heat killed Candida albicans (HKCA) were injected in vivo. The animals were sacrificed 18h later and DC-enriched fractions were isolated from the spleens. The results are as follow: generally, in the cytoplasm of DC, no phagocytic markers were identified except a few of DC ingested a small amount of CC in vivo and few CA occationally in vitro, while M? under the same conditions, ingested a lot of the substances mentioned above. It indicates that spleen M? phagocytose actively either to immunogenic or non-immunogenic, opsonized or non-opsonized particles (especially to opsonized particles), while DC in the same preparations are not.

THE ULTRASTRUCTURAL OBSERVATIONS ON THE CHANGES OF FOLLICULAR DENDRITIC CELLS IN THE SPLEEN OF THE POSTNATAL RATS AT THE AGES OF 21 TO 48 DAYS / 解剖学报

In this experiment, the PAP was used as a specific marker to label the follicular dendritic cells (FDC) and their possible precursors in the spleens of postnatal rats at 21, 27, 34, 41 and 48 days respectively, and the changes of the labeled cells were studied under TEM. In 21-day-old rats the labeled cells were of the histological feature resembling fibroblastic reticulum cells(FRC). As the rats getting elder, the shape and structure of the labeled cells changed. The shape of t he cells and nuclei changed from ellipse to irregular. The heterochromatin decreased and so did the microfilaments in the cytoplasm. The cytoplasmic processes increased in number, length and complexity. The relatively smooth cell surface became folding and invaginating. By the 48 days after birth the labeled cells possessed the features of the FDC. The result implys that the FDC might originate from FRC.