Probing rat brain oxygenation with near-infrared spectroscopy (NIRS) and magnetic resonance imaging (MRI).
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Animals↗
Biomedical subjects
Yu Chen
Publications and source records attributed to Yu Chen.
Temporospatial expression of vascular endothelial growth factor and basic fibroblast growth factor during mandibular distraction osteogenesis.
OBJECTIVE: Distraction osteogenesis is a vascular-dependent process. This study investigated expression patterns of two major angiogenic factors, vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF), in the distracted calluses following mandibular lengthening in a goat model. MATERIAL AND METHODS: Bilateral mandibular osteotomies were performed in 15 young adult goats. After a latency of 7 days, the mandibles were elongated using custom-made distractors with a rate of 1 mm/day for 10 days. Three animals each were sacrificed at the end of the delay phase, at 0, 7, 14, and 28 days after completion of distraction, respectively. The lengthened mandibles were harvested and processed for histological and immunohistochemical examinations. RESULTS: Elevated cellular expression of VEGF and bFGF, with neovascularization in the distraction gap, was observed following mandibular lengthening. VEGF staining was noted in the endothelial cells and osteoblasts. bFGF staining was seen in the fibroblast-like cells, osteoblasts and immature osteocytes. Their strongest expression was found 0-7 days after the end of distraction, and declined with maturation of the newly formed bone. CONCLUSION: A temporal and spatial expression pattern of VEGF and bFGF was found during distraction osteogenesis in goat mandibles. It suggests that distraction forces can stimulate the production of VEGF and bFGF, which contribute to neovascularization and new bone formation during gradual distraction of the mandible. Application of angiogenic factors may be considered as a potential method to enhance angiogenesis and osteogenesis in osteodistraction, especially in sites without enough vascularization.
Animals↗
Lung cancer risk in white and black Americans.
PURPOSE: To test whether differences in smoking-related lung cancer risks in blacks and whites can explain why lung cancer incidence is greater in black males than in white males but about equal in black and white females, given that a greater proportion of blacks are smokers, but smoke far fewer cigarettes per day than do whites. METHODS: A hospital-based case-control study was conducted between 1984 and 1998 that included interviews with 1,710 white male and 1,321 white female cases of histologically confirmed lung cancer, 254 black male and 163 black female cases, and 8,151 controls. Relative risks were estimated via odds ratios using logistic regression, adjusted for age, education, and body mass index. RESULTS: We confirmed prior reports that smoking prevalence is higher but overall dosage is lower among blacks. Overall ORs were similar for blacks and whites, except among the heaviest smoking males (21+ cigarettes per day or 37.5 pack-years), in whom ORs for blacks were considerably greater than for whites. Long-term benefits of cessation were similar for white and black ex-smokers. Smokers of menthol flavored cigarettes were at no greater risk for lung cancer than were smokers of unflavored brands. CONCLUSIONS: Lung cancer risks were similar for whites and blacks with similar smoking habits, except possibly for blacks who were very heavy smokers; this sub-group is unusual in the general population of African American smokers. Explanations of racial disparities in lung cancer risk may need to account for modifying factors including type of cigarette (yield, mentholation), diet, occupation, and host factors such as ability to metabolize mainstream smoke carcinogens.
Black or African American↗
Modified BINOL ligands in asymmetric catalysis.
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Journal Article↗
Long-term improvement of cardiac function in rats after infarction by transplantation of embryonic stem cells.
OBJECTIVE: This study was designed to investigate the feasibility of and potential functional improvement with embryonic stem cell transplantation in rats 32 weeks after myocardial infarction. METHODS: Before cell transplantation, cultured embryonic stem cells were transfected with the complementary DNA of green fluorescent protein to identify engrafted cells in myocardium. Myocardial infarction was induced by ligation of the left coronary artery. Either 3 x 10(5) mouse embryonic stem cells or an equivalent volume of cell-free medium was injected into injured myocardium within 20 minutes after induction of myocardial infarction. RESULTS: Embryonic stem cell transplantation significantly increased the survival rate in rats undergoing myocardial infarction during the experimental period of 32 weeks. Hemodynamic and echocardiographic data showed that embryonic stem cell transplantation significantly improved ventricular function relative to the myocardial infarction plus medium control group. Tissue positive for green fluorescent protein was found in the injured myocardium with cell transplantation. The proportion of myocardium positively immunostained by antibodies against alpha-myosin heavy chain and cardiac troponin I was greater in the infarcted area with embryonic stem cell transplantation than in the injured myocardium with medium injection. Single green fluorescent protein-positive cells with a rod shape and clear striations were observed in cardiomyocytes isolated from infarcted hearts with embryonic stem cell transplantation. In addition, the number of blood vessels in injured myocardium was greater in the cell-transplanted myocardial infarction group than in the medium-injected myocardial infarction group. CONCLUSIONS: Engrafted embryonic stem cells differentiated into cardiomyocytes in injured myocardium, caused an angiogenetic effect, and subsequently improved cardiac function during the 32-week observation period.
Animals↗
Cardiomyocytes overexpressing TNF-alpha attract migration of embryonic stem cells via activation of p38 and c-Jun amino-terminal kinase.
Tumor necrosis factor-alpha (TNF-alpha) plays an important role in the pathogenesis of myocardial infarction. Stem cells are able to regenerate infarcted myocardium. This study investigated whether TNF-alpha was able to induce migration of embryonic stem cells (ESCs) in vitro. We used a Transwell assay in which neonatal rat cardiomyocytes, with or without transfection of TNF-alpha cDNA, were plated in the lower compartments and mouse ESCs tagged with green fluorescent protein were added to the upper compartments. TNF-alpha level was significantly increased in the medium of the lower compartments seeded with TNF-alpha-transfected cardiomyocytes. Compared with the controls, overexpression of TNF-alpha significantly enhanced migration of ESCs to the lower compartments. This enhancement was attenuated by preincubation of ESCs with the antibody against the type II TNF-alpha receptor (TNF-RII), but not by the antibody against the type I TNF-alpha receptor (TNF-RI). Western blot analysis showed that the phosphorylated protein levels of p38 and c-Jun amino-terminal kinase (JNK) were significantly increased in TNF-alpha-treated ESCs. Inhibition of the activity of p38 or JNK significantly attenuated TNF-alpha-induced ESC migration. Our data demonstrate that excessive TNF-alpha stimulates TNF-RII and enhances migration of ESCs in vitro. Activation of p38 and JNK is required for TNF-alpha-enhanced ESC migration.
Animals↗
In vivo continuous-wave optical breast imaging enhanced with Indocyanine Green.
We investigate the uptake of a nontargeted contrast agent by breast tumors using a continuous wave diffuse optical tomography apparatus. The instrument operates in the near-infrared spectral window and employs 16 sources and 16 detectors to collect light in parallel on the surface of the tumor-bearing breast (coronal geometry). In our protocol an extrinsic contrast agent, Indocyanine Green (ICG), was injected by bolus. Three clinical scenarios with three different pathologies were investigated. A two-compartment model was used to analyze the pharmacokinetics of ICG and preprocess the data, and diffuse optical tomography was used for imaging. Localization and delineation of the tumor was achieved in good agreement with a priori information. Moreover, different dynamical features were observed for differing pathologies. The malignant cases exhibited slower rate constants (uptake and outflow) compared to healthy tissue. These results provide further evidence that in vivo pharmacokinetics of ICG in breast tumors may be a useful diagnostic tool for differentiation of benign and malignant pathologies.
Adenocarcinoma↗
Rat corneal allograft survival prolonged by the superantigen staphylococcal enterotoxin B.
PURPOSE: The purpose of this study was to determine the optimal conditions for prolonging corneal allograft survival by inducing anergy with the superantigen staphylococcal enterotoxin B (SEB). METHODS: A rat model of penetrating keratoplasty, whereby Fisher344 donor corneas are implanted into Lewis recipients, was used to evaluate the effects of SEB on inhibiting immune-mediated allograft rejection. To induce anergy, SEB was injected into the peribulbar space of Lewis rats. Furthermore, histopathology and immunofluorescent staining were used to examine the levels of infiltrating CD4(+) and CD8(+) T lymphocytes and NK1.1(+) lymphocytes. RESULTS: By administering SEB, at doses of 90 or 120 micro g/kg 7 days before and after keratoplasty, we suppressed the episode of corneal graft rejection for a median of 12 and 30 days, respectively. In contrast, rejection was observed when 30 or 60 micro g/kg of SEB was administered. After SEB injections, lymphocyte infiltration into the corneal grafts was reduced, and the expression of NK1.1(+) lymphocytes was enhanced, suggesting that anergy may be occurring. Also, there were no differences in the number of infiltrating CD4(+) and CD8(+) T lymphocytes cells between the control group and groups injected with 30 and 120 micro g/kg SEB on postoperative days 10 and 30. CONCLUSIONS: Inducing anergy with the superantigen SEB prolonged corneal graft survival in a rat model of penetrating keratoplasty. Therefore, these results support the possibility of prolonging corneal allograft survival in a clinical setting by preventing immune-mediated rejection through the administration of the superantigen SEB.
Animals↗
Computational analyses of high-throughput protein-protein interaction data.
Protein-protein interactions play important roles in nearly all events that take place in a cell. High-throughput experimental techniques enable the study of protein-protein interactions at the proteome scale through systematic identification of physical interactions among all proteins in an organism. High-throughput protein-protein interaction data, with ever-increasing volume, are becoming the foundation for new biological discoveries. A great challenge to bioinformatics is to manage, analyze, and model these data. In this review, we describe several databases that store, query, and visualize protein-protein interaction data. Comparison between experimental techniques shows that each high-throughput technique such as yeast two-hybrid assay or protein complex identification through mass spectrometry has its limitations in detecting certain types of interactions and they are complementary to each other. In silico methods using protein/DNA sequences, domain and structure information to predict protein-protein interaction can expand the scope of experimental data and increase the confidence of certain protein-protein interaction pairs. Protein-protein interaction data correlate with other types of data, including protein function, subcellular location, and gene expression profile. Highly connected proteins are more likely to be essential based on the analyses of the global architecture of large-scale interaction network in yeast. Use of protein-protein interaction networks, preferably in conjunction with other types of data, allows assignment of cellular functions to novel proteins and derivation of new biological pathways. As demonstrated in our study on the yeast signal transduction pathway for amino acid transport, integration of high-throughput data with traditional biology resources can transform the protein-protein interaction data from noisy information into knowledge of cellular mechanisms.
Animals↗
[Noninvasive evaluation of liver fibrosis in chronic hepatitis B patients].
OBJECTIVE: To investigate the clinical usefulness of noninvasive diagnostic methods in evaluating liver fibrosis in hepatitis B virus (HBV) patients. METHODS: 102 patients with chronic hepatitis B (CHB) were enrolled from Beijing Friendship Hospital Affiliated to Capital University of Medical Sciences. Noninvasive diagnostic methods including ultrasonography, CT, serum markers of liver function and fibrosis, and HBV DNA were performed and compared with histological fibrotic changes in order to establish a noninvasive method for detecting the degree of liver fibrosis. RESULTS: The total score of liver surface, edge, parenchyma echogenicity, intrahepatic vessels, and the size of spleen had a coefficient of 0.822 with fibrotic stage. By receiver operating curve (ROC) analysis, the sensitivity to distinguish cirrhosis from CHB was 86.1% and the specificity was 95.5% if the total ultrasonic score was more than 10. The CT imaging diagnosed liver cirrhosis with a specificity of 100% and a sensitivity of 48.5%. The change of CT values in cirrhotic patients was lower than that in controls and no cirrhotic patients (F=5.805, P<0.01), when the voltage was increased from 100 KV to 140 KV. Except normal controls and S1 group, S2 and S3 group, the level of HA and collagen IV between the other groups were statistically different. The cut-off value of HA to diagnose cirrhosis was 108 (microg/L) with a sensitivity of 72.2% and a specificity of 80.3%. The cut-off value of collagen IV to diagnose cirrhosis was 188 (microg/L) with a sensitivity of 72.2% and a specificity of 78.8%. When ultrasonography was combined with serum markers, the sensitivity was 72.2% and the specificity was 80.3%. CONCLUSION: Both ultrasonography and serum markers are useful to diagnose cirrhosis. The combination of the two examinations is more valuable than any one alone. The characteristic CT imaging has high specificity but low sensitivity in diagnosing early cirrhosis. HA and collagen IV are correlated more closely with the stage of fibrosis, and can reflect the severity of fibrosis.
Adolescent↗
An evaluation of the serological and epidemiological effects of the outer envelope vaccine to leptospira.
BACKGROUND: The Shanghai Institute of Biological Products manufactured successfully a new outer envelope vaccine for leptospira in 1978. It has been confirmed by using animal tests and a number of human body trials that this vaccine is safe and effective, However, results regarding serological and epidemiological effects of the vaccine in population has not been reported. The objective of this study was to evaluate serological and epidemiological effects of this vaccine. METHODS: From May 1998 to May 1999, an evaluation of the serological and epidemiological effects of the outer envelope vaccine for leptospira made by Shanghai Institute of Biological Products was conducted among agricultural population aged 5 to approximately 60 years in an epidemic area of leptospirosis, in Jingzhou District, Jingzhou City, Hubei Province, China by microscopic agglutination test (MAT), cohort study, matched case-control study and screening method. RESULTS: The serological surveillance results of 77 students immunized showed that the successful rates of vaccination with the outer envelope vaccine of L. icterohaemorrhagiae sero-group and L. hebdomadis sero-group leptospira were 79.22% and 77.92%, respectively, the antibody geometric mean titer (GMT) of the two groups were 1:106.71 and 1:63.31, respectively, with 6.7-fold and 4.7-fold rises comparing with the group of those of the antibody before inoculation, and the antibody protective rates of the two groups of outer membrane protein vaccine of leptospira all were 100% at one month after immunization. Higher level antibody against L. icterohaemorrhagiae sero-group leptospira was still maintained at one year after injection. The results of cohort analysis showed that the protective rate of the outer envelope vaccine of leptospira for the same serological groups of leptospira was 75.17%, and the effective index of the vaccine was 4.03. The protective rate of vaccines obtained from 1:2 matched case-control studies was 81.25%, while that estimated by screening method was 75%. CONCLUSIONS: The study results showed that the serological and epidemiological efficiencies of leptospira vaccine all were ideal. In addition, this vaccine had partly protective effect against other sero-groups of leptospira.
Adolescent↗
[Sequence analysis and expression study of BRI gene in two lung adenocarcinoma cell lines with different metastatic potential].
OBJECTIVE: To investigate the sequence of amyloid fibrils (BRI) gene and its expression in two lung adenocarcinoma cell lines AGZY83-a and Anip973 with the same tumor origin but different metastatic potential. METHODS: DNA sequencing, sequential G banding fluorescence in situ hybridization (FISH) and Northern blot were used to analyze the sequence and expression of BRI gene was in two lung adenocarcinoma cell lines with different metastatic potential. RESULTS: The expression of BRI gene was up-regulated in the highly metastatic cell line Anip973 and was down-regulated in the low metastatic cell line AGZY83-a from which the Anip973 was derived. FISH results disclosed that in the two cell lines, the same rearrangements existed in the chromosome region where BRI gene was located, but in Anip973, amplification took place in the chromosome region where BRI gene was located. DNA sequencing results showed different mutations in the 5' untranslated region of BRI gene in the two cell lines. CONCLUSION: The above results revealed that there was no relation between BRI gene differential expression and rearrangements of chromosome. The amplification of the chromosome region where BRI gene was located and the different mutations in the 5' untranslated region of BRI gene probably contributed to the differential expression.
Adaptor Proteins, Signal Transducing↗
[Clinical characteristics and mechanism of liver injury in patients with severe acute respiratory syndrome].
OBJECTIVES: To summarize the clinical features of liver injury in patients with severe acute respiratory syndrome (SARS), providing information for further mechanism and clinical study. METHODS: The clinical and some laboratory data of 154 patients suffered from SARS were collected and analyzed, who were admitted to the isolation wards of Beijing You-an Hospital from March 11 to June 3, 2003. The serum samples were taken from 46 patients to detect IL-1beta, IL-2, IL-4, IL-6, IL-8, IL-10, TNF-alpha, endotoxin and hepatitis related viral inclusions. In addition, 11 patients were detected ultrasonically, and 3 patients were described pathological features. Other two groups including 15 healthy care workers and 22 patients with chronic hepatitis in the same period were selected and analyzed as controls. RESULTS: When being admitted to hospital, serum ALT and (or) AST levels were elevated in 37.7% SARS patients. Some of them (43.1%) were mild, and most of them (56.9%) were moderate. Abnormal liver function mainly resulted from ALT elevation (70.7%), then both ALT and AST elevation (22.4%). The aminotransferases in 75.9% SARS patients normalized within two weeks, while they elevated in four patients during the hospitalization. There was a significant difference in ALT/AST elevation rates between severe and mild clinical type (chi2=19.28, P<0.05). Serum total bilirubin values elevated in 8.4% patients. Serum albumin and prealbumin levels decreased in 24.0% and 28.6% patients, respectively. Creatine kinase (CK) and (or) creatine kinase MB (CK-MB) levels elevated in 72.7% patients when they hospitalized. The six kinds of interleukins and TNF-alpha levels during the first week of hospitalization were higher than those in the fourth week and in control groups (t>or=1.67, P<0.05). The levels of some factors, such as IL-1beta, IL-6 and IL-10 in patients with elevated ALT, were higher than those in ALT normal patients (t>or=2.36, P<0.05). In the first week, only 15.2% patients had elevated serum endotoxin level. Ultrasonic examination and pathological observation showed no special features, compared with those in common acute hepatitis patients. CONCLUSIONS: All the results suggest strongly that there may be a systemic inflammatory response syndrome (SIRS) in most SARS patients in early stage, and the liver damage is only its partial signs. It may be beneficial to suppress cytokines storm in SARS patients in early stage, which will stop the progression of SIRS and release hepatic damage and improve the prognosis of SARS patients.
Adolescent↗
Carcinoembryonic antigen-producing cell-specific oncolytic adenovirus, OV798, for colorectal cancer therapy.
Human carcinoembryonic antigen (CEA) is overexpressed in most colorectal cancers and has been widely used as a clinical marker for the management of colon cancer patients. The transcriptional regulatory elements (TREs) of CEA include two enhancer elements and a promoter in the 5'-flanking region of the CEA gene. By using these elements in different combinations to control reporter gene expression and the replication of adenovirus variants in various tumor cells, we have identified an optimal CEA regulatory cassette that tightly controls gene expression and viral replication in CEA-producing colon cancer cells. One of these variants, OV798, in which this regulatory cassette controls E1A expression, was further characterized. OV798 preferentially replicates in and kills CEA-producing colorectal cancer cell lines such as LoVo and SW1463, but its replication is attenuated by 1000-fold in the CEA-negative cell lines Colo-320DM (colon cancer), PA-1 (ovarian cancer), G361 (melanoma), U118 MG (glioma), and HBL-100 (human breast epithelial cell). The antitumor activity of OV798 was further examined in BALB/c nu/nu mice carrying s.c. human colon tumor xenografts. A single intratumoral administration of OV798 resulted in growth inhibition of human LoVo colon cancer xenografts. Six weeks after treatment, relative tumor volume decreased to 90% of baseline for the OV798 treatment group, compared to an increase to 1200% of baseline at 4 weeks for the vehicle-treated group. In vitro and in vivo characterization indicate that OV798 could be used as a therapy for human colon cancer.
Adenoviridae↗
[Coronary artery bypass grafting after acute myocardial infarction].
OBJECTIVE: To analyze 88 cases of coronary artery bypass grafting (CABG) within 30 days after acute myocardial infarction(AMI). METHODS: 88 cases included 18 cases with emergent angioplasty, 26 cases with postinfarctional angina pectoris, 9 cases with cardiogenic shock and 25 cases with left main lesion. RESULTS: There were 75 cases underwent off pump coronary artery bypass(OPCAB) and 13 cases underwent beating heart CABG with cardiopulmonary bypass(BH-CPB). The mean number of bypass grafts was 3.4 +/- 0.9. Five patients with preoperative cardiogenic shock died after emergent operations. There were 4 cases with postoperative heart failure, 6 cases with PSVT and 2 cases with bradycardial and treated pacemaking. CONCLUSION: It was neccessry and feasible to perform CABG within 30 days after AMI. Both the OPCAB and BH-CPB were safe methods.
Acute Disease↗
[Inhibition of tongue cancer development in nude mice transfected with adenovirus carrying human endostatin gene].
BACKGROUND & OBJECTIVE: The squamous cell carcinoma of tongue is one of the most common malignant tumors of oral cavity. Surgical therapy is now the mainstay of combined treatment for tongue squamous cell Carcinoma with chemotherapy and radiotherapy. The overall 5-year survival rate was about 50%. The antiangiogenesis therapy has become a new approach of the treatment of tongue carcinoma. This paper was designed to study the characteristics of endostatin expression in tongue cancer cell line (Tca8113), human embryonic epithelial cell line (ECV) and the inhibition of carcinogenesis in nude mice, xenografted with Tca8113, after transfected with recombined adenovirus (Ad/hEnd) which was cloned with human endostatin gene in EI mutated region. METHODS: (1) To determine the expression and distribution of endostatin in Tca and ECV cells transfected with Ad/hEnd using immunohistochemistry. To determine the endostatin in supernatants of Tca cells transfected with Ad/hEnd using ELISA method. To examine the characteristics of endostatin gene expression in Tca8113 and ECV cells by Western blot analysis. (2) To determine the inhibition rate of proliferation and apoptosis rate of ECV cells by WST-1 test and flow cytometry (FCM), respectively.(3) To observe the inhibition of tumor growth in xenografted nude mice with Tca8113 cells by Ad/hEnd administration. RESULTS: (1) Immunohistochemistry detection indicated that the endostatin was expressed in cytoplasm of Tca8113 cells and ECV cells transfected with Ad/hEnd. Endostatin expression in the supernatant was dose-dependent with the highest to 597 ng/ml. The expression of endostatin in Tca cells was detectable from 1 day to 7 day. Ad/hEnd inhibited ECV cell growth in dose-dependent manner. (2) FCM showed that Ad/hEnd arrested ECV cells in S and G(2) phase and induced apoptosis.(3) The tumor growth curve showed that Ad/hEnd significantly repressed xenograft tumor growth with Tca cell in nude mice; the inhibition rate on Ad/hEnd administrated groups was 45.8% in the 3rd week. CONCLUSION: Ad/hEnd expressed efficiently in Tca8113 and ECV cells. Ad/hEnd can change the cell cycle distribution of ECV cells and induce apoptosis and inhibit proliferation of ECV cells. Ad/hEnd could inhibit the growth of tongue carcinoma in xenograft nude mice.
Adenoviridae↗
[A comparative study utilizing different methods for establishing an experimental periodontitis model in rats].
OBJECTIVE: To evaluate the experimental periodontitis in rats induced by ligature plus high sugar water with and without infection of periodontopathic bacteria. METHODS: Forty SD rats (5 weeks of age) were randomly divided into a control group (N) and three experimental groups (P1, P2 and P3). All experimental groups were given silk ligatures around the cervix of the second maxillary molars and were provided with drinking water containing 10% glucose. Group P2 was inoculated with P. gingivalis, three times; group P3 was inoculated with P. gingivalis and F. nucleatum, three times. At weeks 0, 2 and 4, microbiological and histological examinations were made; alveolar bone loss was stereoscopically measured as the distance from the cement-enamel junction to the alveolar crest. RESULTS: Microbiological examination indicated that the bacteria inoculated in groups P2 and P3 were successfully colonized and both of P. gingivalis and F. nucleatum were predominant among the bacterial colonies of the examined sites. At week 2, histological examination showed gingival erosion and alveolar bone loss in all experimental groups and periodontal pockets in groups P2 and P3. The most serious lesions were observed in group P3. At week 4, the periodontal destruction in all experimental groups became more severe. CONCLUSION: Ligature, high sugar water combined with mixed infection of periodontopathic bacteria can successfully induce experimental periodontitis in rats.
Animals↗
[Anergy, apoptosis and decreased MHC class I molecule expression of C57BL/6J mouse CD4+ T cells induced by SEB].
AIM: To study the mechanism of peripheral T cell tolerance induced by superantigen Staphylococus aureus enterotoxin B (SAgSEB). METHODS: Splenocytes from C57BL/6J (B6) mice were stimulated with SEB in-vitro. The proliferation of lymphocytes was determined by MTT colorimetry. The apoptosis of anergic T cells, the cells being in the S and G(0)-G(1) phase and MHC-I (H-2K(b)) expression of T cells were analyzed by flow cytometry (FCM). Apoptosis of anergic T cells was also demonstrated by DNA electrophoresis ladder. RESULTS: SEB could induce strong proliferation of CD4+ T cells and the maximal percentage of CD4+ T cells in S phase appeared on 3rd day after SEB stimulation and then decreased, but the changes of percentage of CD4+ T cells in G(0)-G(1) phase was opposite to that in S phase. CD4+ T cells became anergy on 3rd day and apoptosis of anergic CD4+ T cells appeared on 5th day. Percentage of apoptosis cells increased gradually and could not be reversed by addition of anti-CD3 Ab and ConA. Expression of MHC-I (H-2K(b)) was marginally declined accompanied by CD4+ T cell anergy after SEB exposure. CONCLUSION: SEB-induced tolerance may have relation to anergy and apoptosis of CD4+ T cells, and down-regulation of MHC-I molecules.
Animals↗