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991.
We have used a quantitative titration assay for mixed lymphocyte interactions to determine the additivity of responses of rat lymphocyte populations to simultaneous stimulation with major histocompatibility complex alloantigens from pairs of apparently unrelated rat strains. Our inability to detect strict additive stimulation led us to investigate inclusion among allo-reactive lymphocyte populations. After specific depletion of reactivity to PVG by negative selection through an AO × PVG F1 hybrid rat, AO thoracic duct lymphocytes showed an asymmetrical loss of reactivity to the unrelated strains DA and F344. We suggest that this differential loss of reactivity probably reflects alloantigen sharing among rat strains which had been previously undetected using other less sensitive techniques for the quantitation of lymphocyte reactivity after specific depletion of allo-reactive cells. 相似文献
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993.
E. B. Burova I. S. Smirnova A. N. Shatrova I. V. Gonchar N. N. Nikolskii 《Cell and Tissue Biology》2011,5(1):9-14
Interferon gamma (IFNγ) is known to inhibit the proliferation of some transformed cell lines. Recently, we demonstrated the
transactivation of the epidermal growth factor receptor (EGFR) in response to IFNγ (Burova et al., 2007) and provided direct
evidence for the dependence of IFNγ-induced EGFR transactivation on the EGFR expression level in epithelial cells (Gonchar
et al., 2008). This study examines an antiproliferative effect of IFNγ on human epithelial cell lines—A431 and HeLa that express
high levels of EGFR, as well as HEK293 that expresses low levels of EGFR. To characterize the IFNγ-induced changes in these
cells, we studied cell growth, the cell cycle, and induction of apoptosis. The response to IFNγ differed in the compared cell
lines; cell growth was inhibited in both A431 and HeLa cells, but not in HEK293 cells, as was shown by the cell count and
MTT. The cell-cycle phases analyzed by flow cytometry were disturbed in A431 and HeLa cells in response to IFNγ. On the contrary,
in HEK293 cells, the IFNγ treatment did not alter distribution by cell cycle phases. Our results indicate that IFNγ produces
an antiproliferative effect that depends on the increased expression of EGFR in A431 and HeLa cells. Furthermore, it was demonstrated
that IFNγ induced the caspase 3 activation in A431 cells, which suggests the involvement of active caspase 3 in the IFNγ-induced
apoptosis. 相似文献
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997.
P. J. Hogarth 《Journal of fish biology》1973,5(1):109-113
Advanced embryos of the viviparous poeciliid fish Xiphophorus hellerii (swordtail) were removed from the site of gestation within the ovary and re-implanted into the peritoneal cavities of unrelated immunologically competent adults of the same species. Most of those transplanted with intact fertilization membranes were normal in appearance, and many were clearly still alive. Those transplanted without a fertilization membrane were all dead, with lymphocyte infiltration and other evidence of rejection as allografts. The integrity of the membrane in late pregnancy was indicated by swelling of follicles in hypoosmotic liquid. It was concluded that the fertilization membrane is capable of protecting an antigenically foreign embryo in an immunologically hostile environment, and that it probably serves this function during normal pregnancy. 相似文献
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