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1.
Paclitaxel enhances macrophage IL-12 production in tumor-bearing hosts through nitric oxide. 总被引:9,自引:0,他引:9
D W Mullins C J Burger K D Elgert 《Journal of immunology (Baltimore, Md. : 1950)》1999,162(11):6811-6818
Tumor-induced macrophages (Mphis) mediate immunosuppression, in part, through increased production of factors that suppress T cell responsiveness and underproduction of positive regulatory cytokines. Pretreatment of tumor-bearing host (TBH) Mphis with the anticancer agent paclitaxel (Taxol) partially reverses tumor-induced Mphi suppressor activity, suggesting that paclitaxel may restore TBH Mphi production of proimmune factors. Because paclitaxel demonstrates LPS-mimetic capabilities and increased production of the LPS-induced immunostimulatory cytokine IL-12 could account for enhanced T cell responsiveness, we investigated whether paclitaxel induces Mphi IL-12 production. Tumor growth significantly down-regulated Mphi IL-12 p70 production through selective dysregulation of IL-12 p40 expression. LPS stimulation failed to overcome tumor-induced dysregulation of p40 expression. In contrast, paclitaxel significantly enhanced both normal host and TBH Mphi IL-12 p70 production in vitro, although TBH Mphi IL-12 production was lower than that of similarly treated normal host Mphis. Paclitaxel enhanced p40 expression in a dose-dependent manner. Through reconstituted Mphi IL-12 expression, paclitaxel pretreatment relieved tumor-induced Mphi suppression of T cell alloreactivity. Blocking Mphi NO suppressed paclitaxel's ability to induce IL-12 production. This suggests that paclitaxel-induced activities may involve a NO-mediated autocrine induction pathway. Collectively, these data demonstrate that paclitaxel restores IL-12 production in the TBH and ascribe a novel immunotherapeutic component to the pleiotropic activities of NO. Through its capacity to induce IL-12 production, paclitaxel may contribute to the correction of tumor-induced immune dysfunction. 相似文献
2.
3.
The diminished production of arachidonic acid oxygenation products by elicited mouse peritoneal macrophages: possible mechanisms 总被引:12,自引:0,他引:12
4.
The in vitro DNA-cleaving activity of neocarzinostatin, a protein antibiotic, is strongly but reversibly inhibited by anaerobiosis. Half-maximal activity is seen in the presence of 0.25 mM O2. The stability of neocarzinostatin, as demonstrated by its ability to cleave DNA, is significantly reduced in light. Inactivation by light is complete and irreversible. 相似文献
5.
Structural relatedness of lysis proteins from colicinogenic plasmids and icosahedral coliphages 总被引:4,自引:0,他引:4
The host-lysis-inducing functions of phi X174 protein E and MS2 protein L
were recently shown to reside on the N-terminal and C-terminal halves of
the two respective lysis proteins. In the present study it is shown that
the small lysis proteins encoded in various colicinogenic plasmids share
local sequence similarities and certain structural characteristics with the
essential peptides of their coliphage-coded counterparts. Despite their
dissimilar sizes and origins, it is suggested that the colicinogenic lysis
proteins are functionally analogous and evolutionarily related to those of
icosahedral single- stranded DNA and RNA phages.
相似文献
6.
7.
Growth curves,morphology and ultrastructure of ten Paracoccidioides brasiliensis isolates 总被引:1,自引:1,他引:0
Suely Sanae Kashino Vera Lucia Garcia Calich Lucia Mary Singer-Vermes Paulo Alexandre Abrahamsohn Eva Burger 《Mycopathologia》1987,99(2):119-128
The yeast phase of ten P. brasiliensis isolates were studied to characterize their growth pattern, morphology and ultrastructure. Growth curves were determined after counts of total and viable fungi units (FU) during 20 days. Three growth patterns were observed: slow, reaching approximately 10–30× 106 FU/tube (Pb 18, Pb 265 and PB 2); intermediate, reaching 60–150×106 FU/tube (IVIC Pb 9, IVIC Pb 267, Pb SN, Pb Vitor and Pb Campo Grande) and fast, reaching 180–370×106 FU/tube (Pb 2052 and Pb 192). The highest percentage of viable cells occurred on the 6th day of culture for Pb 192, Pb Campo Grande, Pb 2052 and IVIC Pb 9; on the 8th day for Pb Vitor, Pb SN, Pb 18 and IVIC Pb 267; on the 10th day for Pb 265 and on the 12th day of culture for Pb 2. Mean generation times varied from approximately 21.2 (Pb 2052) to 102.6 hours (Pb 265). The isolates showed similar morphology, except IVIC Pb 267 which did not present a typical yeast-phase at 35°C and the two fast-growing isolates (Pb 2052 and Pb 192) that presented smaller cell sizes and less tendency to clump. The ultrastructure of the isolates was similar: the cell walls presented a width of 0.1 to 0.2 °; the mitochondria presented few cristae and had equivalent patterns of distribution and morphology; the endoplasmic reticulum was scanty, presenting narrow cisternae; the vacuoles, empty or filled with electrondense material, were numerous and two to five nuclei with pores were constantly observed. 相似文献
8.
A 60-fold increase in ethylene content was observed in stem cuttings of chrysanthemum (Chrysanthemum × morifolium Ramat.) held in aero-hydroponics under anoxic conditions during the 8 to 12 days necessary for adventitious root formation. Ethylene, 1-aminocyclopropane-1-carboxylic acid, and 10-(malonylamino) cyclopropane-1-carboxylic acid contents were highest in the immersed portion of the cuttings, but there was substantial ethylene produced by the anoxic, misted portions of the cutting above the liquid. Application of ethylene (10 microliters per liter) to chrysanthemum cuttings stimulated root development in cuttings held in high dissolved oxygen concentrations (8.0 milligrams per liter). Since the application of ethylene did not inhibit rooting in cuttings held at low dissolved oxygen concentrations (2.0 milligrams per liter), the inhibition of rooting under low oxygen concentrations is not mediated by the observed increase in endogenous ethylene content. 相似文献
9.
Cecilia PC Soh Alastair SR Donald James Feeney Walter TJ Morgan Winifred M Watkins 《Glycoconjugate journal》1989,6(3):319-332
The tetrasaccharides GalNAcß1-4[NeuAc2-3]Galß1-4Glc and GalNAcß1-4[NeuAc2-3]Galß1-4GlcNAc were synthesised by enzymic transfer of GalNAc from UDP-GalNAc to 3-sialyllactose (NeuAc2-3Galß1-4Glc) and 3-sialyl-N-acetyllactosamine (NeuAc2-3Galß1-4GlcNAc). The structures of the products were established by methylation and1H-500 MHz NMR spectroscopy. In Sda serological tests the product formed with 3-sialyl-N-acetyllactosamine was highly active whereas that formed with 3-sialyllactose had only weak activity. 相似文献
10.
Many cell lines respond to mitogenic stimuli (serum, growth factors) with rapid phosphorylation of the ribosomal protein S6 at several serine sites. We have tried to identify the protein kinase(s) mediating this effect of growth stimuli. Examining post-DEAE chromatography fractions of S49 kin- cell extracts, we could detect a highly active effector-independent S6 kinase with specificity for serine residues. The study was extended to the presumably homologous human enzyme, using HeLa S3 cells as model system. Activity yields increased up to sevenfold when exhausted HeLa cells were supplied with fresh medium plus serum. The enzyme uses ATP, not GTP, as cosubstrate, 40-S or 80-S (reassociated from subunits) ribosomal particles being substrate. The optimal K+ concentration, measured at 3 mM Mg2+, is 35 mM. Under optimized assay conditions S6 phosphorylation proceeded faster in vitro than it appeared to do in vivo. The apparent Mr of the enzyme, as estimated by gel filtration on Sephadex G-100, is 56,000 (determination in the presence of 200 mM KCl in 25 mM phosphate buffer). Tighter binding to DEAE-Sephacel and higher specificity for S6 distinguishes this enzyme from the following S6-phosphorylating protein kinases: protein kinase C, protease-activated kinase II, histone-4 phosphotransferase and an enzyme with the properties of casein kinase I. In published summaries of observations shown here and in a follow-up study with chick embryo fibroblasts, the enzyme(s) has been referred to as mitogen-responsive S6 kinase(s) [Martini, O. H. W. and Lawen, A. (1985) in Hormones and cell regulation (Dumont, J. E., Hamprecht, B. and Nunez, J., eds) vol. 9, pp. 411-412, Elsevier Company, North-Holland, Amsterdam; Lawen, A. and Martini, O. H. W. (1985) FEBS Lett. 185, 272-276]. 相似文献