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1.
2.
Selective cytotoxicity of marine algae extracts to several human leukemic cell lines 总被引:4,自引:0,他引:4
Extracts from 8 species of marine algae which showed selective cytotoxicity in our previous screening program, were further
examined for cytotoxic spectra to five human leukemic cell lines. The extract from a red alga, Amphiroa zonata exhibited strong cytotoxicity to all human leukemic cell lines tested and murine leukemic cells L1210 at the final concentrations
from 15 to 375 μg ml−1. Then the cytotoxicity was not found in normal human fibroblast HDF and murine normal cells NIH-3T3. The active extract fraction
from this alga was soluble in higher polar organic solvents and water and heat-stable. The extract from a brown alga Dilophus
okamurae with weak selective cytotoxic activity to L1210 cells exhibited not only strong cytotoxicity to L1210, but also to
human leukemic cells, HL60 and MOLT-4 at 50 μg ml-1. While, the extract from a green alga, Cladophoropsis vaucheriaeformis with most selective cytotoxic activity, did not show
cytotoxicity to any human leukemic cell lines tested at 50 μg ml-1. However, this extract showed strong cytotoxicity to two human leukemic cell lines and NIH-3T3 at 100 μg ml−1. Thus, it was considered that a red alga, Amphiroa zonata might be suitable natural source for development of anti-cancer agents without side-effect.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
3.
Dynamics of CD4^+CD25^+ T Cells in Spleens and Mesenteric Lymph Nodes of Mice Infected with Schistosomajaponicum 总被引:2,自引:0,他引:2
Cai XP Zhang H Zhang YC Wang Y Su C Ji MJ Wu HW Zhu X Zhang ZS Wu GL 《Acta biochimica et biophysica Sinica》2006,38(5):299-304
CD4~ CD25~ T cells play a major role in modulating immune response,but few reports havebeen published about schistosomiasis.Here,we investigated the changes in CD4~ CD25~ T cell populations inspleens and mesenteric lymph nodes of mice infected with Schistosoma japonicum.The proportions ofCD4~ CD25~ T cells in total CD4~ T cells were analyzed by flow cytometry.CD25 and Foxp3 expression wasmeasured by real-time quantitative polymerase chain reaction.The suppressive activities of CD4~ CD25~ Tcells were detected by in vitro proliferation of splenocytes.Evidence showed that the percentage of CD4~ CD25~ T cells was the same as controls 3 weeks post-infection.At the acute stage of infection,the percentagedecreased significantly.However,at the chronic stage of infection,it rebounded to normal levels or evenhigher.The expression of the CD25 and Foxp3 showed gradual increase along with the infection progress.Invitro experiment also showed the strong suppressive effect of CD4~ CD25~ T cells,isolated during the chronicstage,on proliferation of the CD25~-splenocytes.This is the first time that the dynamics of CD4~ CD25~ T cellpopulations was demonstrated in mice infected with schistosomiasis.In conclusion,our data indicated thatCD4~ CD25~ cells might be involved in the immune modulation during S.japonicum infection,which en-hances current knowledge of the mechanisms of the immuno-downregulation and re-infection inschistosomiasis. 相似文献
4.
Waldenstr?m macroglobulinemia (WM) is a neoplasm of mature IgM-expressing B-lymphocytes that is characterized by the occurrence of a monoclonal IgM (mIgM) paraprotein in blood serum and the infiltration of hematopoietic bone marrow with malignant lymphoplasmacytic cells. WM remains incurable despite the development of new therapeutic options. Owing in large measure to having a low incidence, indolent clinical course and good long-term control with proper clinical management, WM has not been investigated as extensively as other B-lineage neoplasms. Major knowledge gaps in our understanding of the natural history of WM include the cell of origin. With that shortcoming in mind, here we discuss the significance of a specific gain-of-function mutation in the adapter protein, myeloid differentiation primary response 88 (MYD88), that occurs with near-complete penetrance in WM and suggests that tumor development is under strong selective pressure for elevated MYD88 signaling. This provides an intriguing link to IgM memory B-cells, which comprise two types of B-lymphocytes ( natural effector IgM+IgD+ cells and IgM-only IgM+IgD- cells ) that depend, in part, on MYD88 signaling and constitute intriguing candidates for WM’s cell of origin. We review the features and developmental history of IgM memory in greater depth and propose that WM may be derived from primitive innate-like B-cells ( marginal zone B-cells and B1 B-cells ) that feed the IgM memory compartment. We conclude with a model of MYD88-dependent tumor development in the mature B-cell lineage that considers two different ( convergent or divergent) oncogenesis pathways with respect to the cells of origin. 相似文献
5.
CHAURMW LAUASK 《Cell research》1990,1(2):181-190
An immunostimulatory factor was identified to be secreted by antigen-pulsed macrophages.This factor was able to induce the generation of antigen specific T helper lymphocytes in vitro as well as in vivo.Further in vitro experiments testing for the genetic restriction of this factor indicated that it is a geneticallyrestricted antigen specific factor (ASF).The Cunningham plaque assay was used to quantify the generation of T helper lymphocytes by measuring the number of plaque forming cells after sequential incubations of antigen-qulsed macrophages with T lymphocytes,and then spleen cells,and finally the TNP-coated sheep red blood cells. 相似文献
6.
Soil salt and nutrient concentration in the rhizosphere of desert halophytes 总被引:2,自引:0,他引:2 下载免费PDF全文
North-West China is an arid region where halophyte plants are rich. Very little is known on the rhizospheric soil of the halophytes in this arid desert region. We conducted a rhizobag experiment on the desert Solonchak soil to investigate the salt and nutrient content in the rhizospheric soil of the desert halophytes. The total salt and the concentrations of 8 major kinds of salt ions increased in the rhizosphere of both succulent halophytes and salt secreting halophytes, but this increase was insignificant for salt-resisting halophytes. Accumulation of Cl– and Na+ is the most significant among the 8 major kinds of salt ions. Accumulation of Cl– was more significant than that of SO42– in succulent halophytes and salt secreting halophytes. The Na+/K+, Na+/Ca2+ and Na+/Mg2+ ratios in the rhizosphere of all 7 kinds of halophytes were higher than those in the bulk soil. Total N increased significantly in the rhizosphere, but total P and total K decreased. However, the available N, P and K in the rhizosphere of the 7 kinds of halophytes except Phragmites communis Trin. behaved in such an opposite way that available N decreased but available P and available K increased. The ionic contents in the aboveground parts were higher than those in the underground parts of the 7 kinds of halophytes, in particular of both the succulent halophytes and the salt secreting halophytes. Accumulation of Cl– and Na+ in the aboveground parts of the plants was the most significant among that of the 8 major kinds of salt ions. 相似文献
7.
HUANG Ke LIU PengFei LI Xiang CHEN ShuBin WANG LiHui QIN Li SU ZhengHui HUANG WenHao LIU JuLi JIA Bei LIU Jie CAI JingLei PEI DuanQing PAN GuangJin 《中国科学:生命科学英文版》2014,57(2):162-170
The breakthrough development of induced pluripotent stem cells(iPSCs)raises the prospect of patient-specific treatment for many diseases through the replacement of affected cells.However,whether iPSC-derived functional cell lineages generate a deleterious immune response upon auto-transplantation remains unclear.In this study,we differentiated five human iPSC lines from skin fibroblasts and urine cells into neural progenitor cells(NPCs)and analyzed their immunogenicity.Through co-culture with autogenous peripheral blood mononuclear cells(PBMCs),we showed that both somatic cells and iPSC-derived NPCs do not stimulate significant autogenous PBMC proliferation.However,a significant immune reaction was detected when these cells were co-cultured with allogenous PBMCs.Furthermore,no significant expression of perforin or granzyme B was detected following stimulation of autogenous immune effector cells(CD3+CD8 T cells,CD3+CD8+T cells or CD3 CD56+NK cells)by NPCs in both PBMC and T cell co-culture systems.These results suggest that human iPSC-derived NPCs may not initiate an immune response in autogenous transplants,and thus set a base for further preclinical evaluation of human iPSCs. 相似文献
8.
Multipotent mesenchymal stromal cells (MSC) can be isolated and efficiently expanded from almost every single body tissue and have the ability of self-renewal and differentiation into various mesodermal cell lineages. Moreover, these cells are considered immunologically privileged, related to a lack of surface expression of costimulatory molecules required for complete T cell activation. Recently, it has been observed that MSC are capable of suppressing the immune response by inhibiting the maturation of dendritic cells and suppressing the function of T lymphocytes, B lymphocytes and natural killer cells in autoimmune and inflammatory diseases as a new strategy for immunosuppression. The understanding of immune regulation mechanisms by MSC is necessary for their use as immunotherapy in clinical applications for several diseases. 相似文献
9.
John H. Todd Mary Ann Sens Debra J. Hazen-Martin John E. Bylander Brendan J. Smyth Donald A. Sens 《In vitro cellular & developmental biology. Animal》1993,29(5):371-378
Summary Monolayers of human proximal tubule (HPT) cells, when grown on permeable supports and mounted in Ussing chambers, spontaneously
display a transepithelial potential difference (PD), short-circuit current (Isc), and transepithelial specific resistance
(RT). These electrical parameters were used to determine the degree of heterogeneity among independent isolates of human proximal
tubule cell cultures. Seventeen independent isolates of cells were assessed, totaling 260 individual determinations of spontaneous
electrical properties. On average, these cell monolayers displayed an apicalnegative PD of 1.5 ± 0.1 mV, an Isc of 2.7 ± 0.2
μA/cm2, and an RT of 480 ± 19 ohms × cm2. Each independent cell isolate, however, displayed electrical values within a narrow range, in some cases allowing isolates
to be distinguished from one another. The individual isolates were also assessed for Na-coupled glucose transport, Na+,K+-ATPase activity, cAMP stimulation by parathyroid hormone (PTH), forskolin stimulation of Isc, and ouabain inhibition. With
the exception of a strong correlation between Na+,K+-ATPase activity and Isc, these parameters, in contrast to electrical properties, were found to be consistent and did not
reveal distinctions among the isolates. HPT cell cultures seem to consistently retain important features of proximal tubule
differentiation while maintaining the variability, as demonstrated by electrical properties, that might be expected of cells
isolated from a random population. 相似文献
10.
Pituitaries were collected from a common carp,yprinss carpi, belonging to vitellogenic phase and cells were disaggregated by using 0.3% collagenase and 0.05% tsypsin. Enzymatically
dispersed cells were incubatedin vitro in Ca2+-free medium to observe the effect ofCanna punctatus GnRH (cGnRH) and Ca2+ on pituitary cell cAMP accumulation. Addition of cGnRH (20 Big) to pituitary cell incubation (6 × 104 cells/well) containing 4 mM theophylline, a phosphodiesterase inhibitor, caused two-fold increase of cAMP accumulation in
comparison to control, Addition of Ca2+ (2 mM) to cGnRH further augmented cAMP accumulation, i.e., four-fold as compared to control. Increasing concentrations of
cGnRH in the presence of Ca2+ resulted in a dose-dependent increase in cAMP accumulation. To examine the specificity of Ca2+ augmentory effect on cGnRH-stimulated pituitary cell cAMP accumulation, a specific Ca2+-channel blocker, verapamil was used, At 3 μM dose verapamil completely waived Ca2+-augmentation of cGnRH stimulatory effect on cAMP. Interestingly, verapamil also significantly inhibited cGnRH stimulation
of cAMP in the Ca2+-free medium. Extent of Ca2+ plus cGnRH stimulatory effect on cAMP was further increased by the addition of 25 pmol of calmodulin, a Ca2+-carrier protein, Addition of verapamil to this system strongly inhibited Ca2+ and ealmodulin augnientory effect on cGnRH. Reduced level of cAMP in the pituitary cell due to verapamil was even lower than
that of cGnRH plus ealmodulin incubation. Data indicates a contamination of Ca2+ in an apparently Ca2+-free medium, Results suggest that in lower vertebrate, i.e., fish, GnRH stimulation of pituitary cell cAMP is dependent on
extracellulnr Ca2+ and incubation of pituitary cell in Ca2+-free medium is truly not free of Ca2+. 相似文献
11.
Ryanodine receptors (RyRs) play a key role in the generalization and spreading of calcium waves in excitable cells; however,
the question of the existence of functionally active RyRs in nonexcitable cells demonstrating the capacity for exocytosis
(e.g., salivary gland acini) remains open. We studied changes in the total amount of calcium stored in the endoplasmic reticulum
(ER) of acinar cells of the submandibular salivary gland of rats and changes in the concentration of ionized Ca2+ inside the ER ([Ca2+]ER) using, respectively, a metallochrome dye, arsenazo III, and a low-affinity fluorescent dye, mag-fura 2/AM. In permeabilized
cells, caffeine caused dose-dependent decreases in the total amount of calcium and concentration of ionized calcium. The effective
concentration of caffeine providing a 50% drop in the [Ca2+]ER (EC50) was, on average, 7.3 ± 1.1 mM. The caffeine-induced drop in the [Ca2+]ER was insensitive to heparin; in addition, it was blocked by high concentrations (100 μM) of ryanodine, potentiated by ryanodine
applied in mild concentrations (10 μM), and also demonstrated a bell-shaped dependence on the concentration of cytoplasmic
Ca2+. Such peculiarities are typical characteristics of the RyR-mediated reaction. Therefore, functional RyRs whose activation
results in a transient release of calcium from the ER are present in acinar cells of the submandibular salivary gland.
Neirofiziologiya/Neurophysiology, Vol. 39, No. 2, pp. 107–112, March–April, 2007. 相似文献
12.
Samples of surface (0–10 cm) and subsurface soils (10–20 cm) were collected using a grid sampling method in July and September in order to study the spatial and temporal distribution patterns of all forms of nitrogen and total nitrogen (TN) and the relationships between nitrogen concentrations and selected soil properties in Fulaowenpao wetland, a typical inland alkaline wetland. Results showed that there existed obvious heterogeneity at spatial and temporal scales. Generally, higher spatial variability for nitrate nitrogen (NO3-–N), ammonium nitrogen (NH4+–N) and available nitrogen (AN) were observed compared to organic nitrogen (Org-N) and TN. At the spatial scale, concentrations of NO3-–N, NH4+–N and AN in surface soils were higher than those in subsurface soils, but no significant differences were observed between both soil layers (p < 0.05). However, concentrations of Org-N and TN were significantly higher in surface soils compared to subsurface soils (p < 0.05), and both of them had similar spatial distribution patterns. At the temporal scale, with the exception of NH4+–N in both soil layers and NO3-–N in subsurface soils, concentrations of all the other forms of nitrogen and TN were generally higher in September than them in July, while there were no significant differences between both sampling periods (p < 0.05) except for AN (p < 0.01) in both soil layers. Correlation analysis showed that AN, Org-N and TN were significantly and positively correlated with soil organic matter, total phosphorous, and clay contents, while they were significantly negatively correlated with soil pH values; NO3-–N was also correlated with soil organic matter and total phosphorous, however, NH4+–N was only closely lined to water contents. 相似文献
13.
Spatial and temporal distribution patterns of nitrogen in marsh soils from an inland alkaline wetland – A case study of Fulaowenpao wetland, China 总被引:1,自引:0,他引:1 下载免费PDF全文
Samples of surface (0–10 cm) and subsurface soils (10–20 cm) were collected using a grid sampling method in July and September in order to study the spatial and temporal distribution patterns of all forms of nitrogen and total nitrogen (TN) and the relationships between nitrogen concentrations and selected soil properties in Fulaowenpao wetland, a typical inland alkaline wetland. Results showed that there existed obvious heterogeneity at spatial and temporal scales. Generally, higher spatial variability for nitrate nitrogen (NO3-–N), ammonium nitrogen (NH4+–N) and available nitrogen (AN) were observed compared to organic nitrogen (Org-N) and TN. At the spatial scale, concentrations of NO3-–N, NH4+–N and AN in surface soils were higher than those in subsurface soils, but no significant differences were observed between both soil layers (p < 0.05). However, concentrations of Org-N and TN were significantly higher in surface soils compared to subsurface soils (p < 0.05), and both of them had similar spatial distribution patterns. At the temporal scale, with the exception of NH4+–N in both soil layers and NO3-–N in subsurface soils, concentrations of all the other forms of nitrogen and TN were generally higher in September than them in July, while there were no significant differences between both sampling periods (p < 0.05) except for AN (p < 0.01) in both soil layers. Correlation analysis showed that AN, Org-N and TN were significantly and positively correlated with soil organic matter, total phosphorous, and clay contents, while they were significantly negatively correlated with soil pH values; NO3-–N was also correlated with soil organic matter and total phosphorous, however, NH4+–N was only closely lined to water contents. 相似文献
14.
The ammonium uptake by cucumber seedlings was estimated from ammonium ions depletion in an uptake solution. The uptake of
NH
4
+
was decreased by about 60 % after one hour and by about 90 % after two hours of 100 μM Cu2+ treatment. On the contrary the accumulation of ammonium in roots of Cu2+-treated seedlings at the same time was higher than in the control. Cu2+ in the concentration inhibiting NH
4
+
absorption during one hour inhibited also glutamine synthetase (GS) (EC 6.3.1.2) and NADH-glutamate dehydrogenase (NADH-GDH)
(EC 1.4.1.2) activities both localized in the roots of seedlings. After one hour and at least up to the 4th hour Cu2+ accumulated mainly in roots (95 %). It was probably the reason of the GS activity in cotyledons of seedling treated with
Cu2+ that it was at the same level as in the control. NADH-GDH activity in cotylcdons after one hour of the Cu2+ treatment was lower than in the control but the influence of Cu2+ action on the activity of this enzyme in roots was by far stronger. 100 μM Cu2+ did not affect the activities of both enzymes in in vitro experiments. Copper added into the incubation medium in 1000 μM concentration decreased GS activity, but still did not change
NADH-GDH activity. These results suggested the indirect Cu2+ action on the investigated enzymes in in vivo experiments. However, no substantial effect on enzyme activities extracted from control plants was observed after the addition
of the extract from Cu2+-treated plants into the incubation medium.
The data suggest that the influence of Cu2+ on uptake and assimilation of ammonium may be connected not only with changes of plasma membrane properties in the root cells
of Cu2+ treated seedlings but also with Cu2+ action on two major enzymes involved in NH
4
+
assimilation: glutamate synthetase and NADH-glutamate dehydrogenase. 相似文献
15.
Gerasimos S. Filippatos W. Frank Hughes Renli Qiao J. Iasha Sznajder Bruce D. Uhal 《In vitro cellular & developmental biology. Animal》1997,33(3):195-200
Summary Active transport of sodium by pulmonary alveolar epithelial cells (AEC) is believed to be an important component of edema
clearance in the normal and injured lung. Data supporting this premise have come from measurements of sodium movement across
AEC monolayers or from perfused lung model systems. However, direct measurement of fluid flux across AEC monolayers has not
been reported. In the present work, AEC were studied with an experimental system for the measurement of fluid flux (Jv) across
functionally intact cell monolayers. Primary adult rat type II alveolar epithelial cells were cultured on 0.8 μm nuleopore
filters previously coated with gelatin and fibronectin. Intact monolayers were verified by high electrical resistance (> 1000
Θ) at 4–5 d of primary culture. At the same time interval, transmission electron microscopy revealed cells with type I cell-like
morphology throughout the monolayer. These were characterized by both adherens and tight junctional attachments. Fluid flux
across the monolayers was measured volumetrically over a period of 2 h in the presence of HEPES-buffered DMEM containing 3%
fatty acid-free bovine serum albumin. Flux (Jv) was inhibited 39% by 1 × 10−4
M ouabain (P < 0.01) and 27% by 5 × 10−4
M amiloride (P < 0.05). These data support the concept that AEC Na+/K+-ATPase and Na+ transport systems are important determinants of AEC transepithelial fluid movement in vitro. 相似文献
16.
Hermenio C. Lima Francisco H. F. Costa Alexandre H. Sampaio Samya A. Neves Norma M. B. Benevides Darlio I. A. Teixeira David J. Rogers Ana Lúcia P. Freitas 《Journal of applied phycology》1998,10(2):153-162
Lectins are powerful stimulants of quiescent peripheral blood lymphocytes. They can induce blast transformation leading to
mitosis of these cells in vitro. We report here the dose-dependent proliferative curve for human peripheral blood monouclear
cells (PBMC) stimulated by the lectin amansin, from Amansia multifida. Amansin stimulated proliferation of (PBMC) at relatively
low concentrations (3.12 to 12.5 μg mL-1). We observed also a gradual reduction in mitogenic capacity with progressive increase in the lectin concentration above
12.5 μg mL-1. This decrease in the mitogenic potential did not result from a toxic effect on the cells, and was predominant at a lectin
concentration above 50 μg mL-1. This decrease in lymphocyte proliferation could be blocked by avidin and could not be overcome by IL-2 or another lectin
(Con Br) at stimulatory concentrations. Additionally, we observed that cells incubated at stimulatory concentrations of amansin
produced IFN-γ. Analysis of the culture supernatants established a direct correlation between the IFN-γ and the mitogenic
and anti-mitogenic capacity of amansin.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
17.
Bone marrow mesenchymal stem cells (BMSCs) have the ability of self-renewal and multi-directional differentiation. Recent
reports showed that BMSCs could differentiate into endocrine cells of pancreas. However, the differentiation is not efficient
enough to produce insulin-producing cells for the future therapeutic use. Pdx-1 is a crucial regulator for pancreatic development. Therefore we constructed a eukaryotic expression vector containing Pdx-1 to determine the effect of Pdx-1 expression on differentiation of BMSCs in vitro. The results showed that BMSCs could self-assemble to form functional pancreatic islet-like structures after differentiation
in vitro. The proportion of insulin-producing cells differentiated from Pdx-1+BMSCs was 28.23%±2.56%, higher than that from BMSCs transfected with vacant vector and Pdx-1 − BMSCs (7.23%±1.56% and 4.08%±2.69% respectively) by flow cytometry. Immunocytochemical examination also testified the expression
of multiple β-cells-specific genes such as insulin, glucagons, somatostatin in differentiated BMSCs. The results also revealed
that the expressions of genes mentioned above in Pdx-1+BMSCs were higher than that in Pdx-1−BMSCs, which was confirmed by Western blotting analysis and RT-PCR. Glucose-induced insulin secretion from Pdx-1+BMSCs in 5mmol/L and 25mmol/L glocuse was (56.61±4.82) μU/mL and (115.29±2.56) μU/mL respectively, which were much higher
than those from Pdx-1−BMSCs((25.53±6.49) μU/mL and (53.26±7.56) μU/mL respectively). Grafted animals were able to maintain their body weight and
survive for relatively longer periods of time than hyperglycemic sham-grafted controls, which demonstrated an overall beneficial
effect of the grafted cells on the health of the animals. These findings thus suggested that exogenous expression of Pdx-1 should provide a promising approach for efficiently producing islet-like cells from BMSCs for the future therapeutic use
in diabetic patients. 相似文献
18.
Summary Interactions between pachytene spermatocytes and Sertoli cells were investigated using the bicameral culture chamber system.
Pachytene spermatocytes were isolated from adult rats with a purity in excess of 90% by centrifugal elutriation. The pachytene
spermatocytes were cultured in a defined media and pachytene spermatocyte protein prepared from the conditioned media by dialysis
and lyophilization. This pachytene spermatocyte protein was reconstituted at various concentrations and incubated with confluent
epithelial sheets of immature Sertoli cells cultured in bicameral chambers. Pachytene spermatocyte protein stimulated secretion
of total [35S]methionine-labeled protein from Sertoli cells in a dose-dependent manner predominantly in an apical direction. This stimulatory
effect of pachytene spermatocyte protein was domain specific from the apical surface of Sertoli cells, and seemed specific
for secretion because total intracellular protein did not increase under the influence of pachytene spermatocyte protein.
Pachytene spermatocyte protein and follicle-stimulating hormone additively stimulated Sertoli cell secretion. The physicochemical
characteristics of the stimulatory pachytene spermatocyte protein are indicative of heat stability, whereas the stimulatory
pachytene spermatocyte protein exhibit acid, dithiothreitol and trypsin sensitivity, and partial urea sensitivity. Furthermore,
Sertoli cell secretion of ceruloplasmin, sulfated glycoprotein-1, sulfated glycoprotein-2, and transferrin in response to
various concentrations of pachytene spermatocyte protein were determined by immunoprecipitate of these [35S]methionine-labeled proteins with polyclonal antibodies. Maximal stimulation of ceruloplasmin and sulfated glycoprotein-1
secretion from Sertoli cells was observed at a dose of 50 μg/ml pachytene spermatocyte protein, whereas maximal stimulation
of sulfated glycoprotein-2 and transferrin secretion from Sertoli cells was observed at a dose of 100 μg/ml of pachytene spermatocyte
protein. These results suggest that pachytene spermatocytes modulate Sertoli cell secretory function of at least four proteins
in the regulation of spermatogenesis.
Supported by grant #DCB-8915930 (D. D.) from the National Science Foundation, Washington, DC. 相似文献
19.
Downregulation of CD4+CD25+ regulatory T cells may underlie enhanced Th1 immunity caused by immunization with activated autologous T cells 总被引:2,自引:0,他引:2
Cao Q Wang L Du F Sheng H Zhang Y Wu J Shen B Shen T Zhang J Li D Li N 《Cell research》2007,17(7):627-637
Regulatory T cells (Treg) play important roles in immune system homeostasis, and may also be involved in tumor immunotolerance by suppressing Th1 immune response which is involved in anti-tumor immunity. We have previously reported that immunization with attenuated activated autologous T cells leads to enhanced anti-tumor immunity and upregulated Thl responses in vivo. However, the underlying molecular mechanisms are not well understood. Here we show that Treg function was significantly downregulated in mice that received immunization of attenuated activated autologous T cells. We found that Foxp3 expression decreased in CD4+CD25+ T cells from the immunized mice. Moreover, CD4+CD25+Foxp3+ Treg obtained from immunized mice exhibited diminished immunosuppression ability compared to those from naive mice. Further analysis showed that the serum of immunized mice contains a high level ofanti-CD25 antibody (about 30 ng/ml, p〈0.01 vs controls). Consistent with a role ofanti-CD25 response in the downregulation of Treg, adoptive transfer of serum from immunized mice to naive mice led to a significant decrease in Treg population and function in recipient mice. The triggering of anti-CD25 response in immunized mice can be explained by the fact that CD25 was induced to a high level in the ConA activated autologous T cells used for immunization. Our results demonstrate for the first time that immunization with attenuated activated autologous T cells evokes anti-CD25 antibody production, which leads to impeded CD4+CD25+Foxp3+ Treg expansion and function in vivo. We suggest that dampened Treg function likely contributes to enhanced Thl response in immunized mice and is at least part of the mechanism underlying the boosted anti-tumor immunity. 相似文献
20.
Sharon P. Andreoli Coleen P. Mallett James A. McAteer Stephen A. Kempson Naomi Fineberg 《In vitro cellular & developmental biology. Animal》1998,34(10):824-830
Summary In renal tubular epithelial cells, oxidant injury results in several metabolic alterations including ATP depletion, decreased
Na+K+ ATPase activity, and altered intracellular sodium and potassium content. To investigate the recovery of LLC-PK1 cells following
oxidant injury and to determine if recovery can be accelerated, we induced oxidant stress in LLC-PK1 cells with 500 μM hydrogen peroxide for 60 min. Identical cohorts of oxidant-stressed cells were incubated in recovery medium without epidermal
growth factor (EGF) or recovery medium containing 25 ng EGF per ml. ATP levels, Na+K+ ATPase activity in whole cells, Na+K+ ATPase activity in disrupted cells, and intracellular sodium and potassium ion content were determined at 0, 5, 24, 48, and
72 h following oxidant injury in each cohort of cells. In oxidant-stressed cells recovering in medium without EGF, ATP levels,
Na+K+ ATPase activity, and intracellular ion content improved but continued to remain substantially lower than control values at
all time points following oxidant stress. In cells recovering in medium with EGF, ATP levels, Na+K+ ATPase activity, and the intracellular potassium-to-sodium ratio were significantly higher at nearly all time points than
values in cells recovering in medium alone. In cells recovering with added EGF, Na+K+ ATPase activity had improved to control levels, whereas ATP levels and intracellular ion content approached control values
by 72 h following oxidant stress. We conclude that oxidant-mediated ATP depletion, altered Na+K+ ATPase activity, and intracellular ion content remain depressed for several d following oxidant stress and that EGF accelerated
recovery of LLC-PK1 cells from oxidant injury. 相似文献