Insight into different host range of three planthoppers by transcriptomic and microbiomic analysis.

Brown planthopper (BPH), white-backed planthopper (WBPH) and small brown planthopper (SBPH), are the closely related rice pests that perform differentially on wheat plants. Using fecundity as a fitness measure, we found that SBPH well-adapted on wheat plants, followed by WBPH, while BPH had the worst performance. The transcriptomic responses of SBPH and BPH to wheat plants have been compared previously. To understand the different fitness mechanisms of three planthoppers, this study first investigated the transcriptomic responses of WBPH to rice and wheat plants. Genes involved in detoxification, transportation and proteasome were significantly enriched in WBPH in response to different diets. Moreover, comparative analysis demonstrated that most co-regulated genes in BPH and SBPH showed different expression changes; whereas most co-regulated genes in BPH and WBPH exhibited similar expression changes. Subsequently, this study also investigated the influences of host plants on the bacterial community of three planthoppers. The three planthoppers harboured distant diversity of bacterial communities. However, there was no dramatic change in bacterial diversity or relative abundance in planthoppers colonized on different hosts. This study illustrates generic and species-specific changes of three rice planthoppers in response to different plants, which deepen our understanding towards the host fitness for planthopper species.

[Establishment and primary clinical application of metabolic evaluation database of urolithiasis].

Objective: To establish the metabolic evaluation database of urolithiasis, perform metabolic evaluation, and provide instructions for treatment and prevention of urolithiasis. Methods: This metabolic evaluation database was developed by JAVA and was established by Oracle11g database and Browser/Server framework. We extracted the clinical data of all patients who had complete information, and analyzed their risk factors of stone formation, stone-related medical history, blood and urine tests results and 24-hour urine analysis. Results: A total of 360 patients diagnosed as urolithiasis were included in this research. Male to female ratio was 1.9∶1, and the urolithiasis was first diagnosed at (35.5±13.5) years old. Family history was positive in 39.7% of patients. Metabolic syndrome occurred in 35.0% of patients. Overweight or obesity occurred in 73.2% and 50.0% of male patients, respectively. Abdominal obesity in 62.3% and 56.1% of male and female patients, respectively. Among all patients, 67.5% had high urine sodium, 53.6% had hypercalciuria, 41.1% had hypocitraturia, 29.7% had hyperuricosuria, 22.5% had hypomagnesuria, 15.8% had hyperoxaluria, 11.7% had hyperphosphoraturia, and 36.4% had low urinary volume. Conclusions: The prevalence of overweight or obesity, abdominal obesity, hypertension, diabetes, and metabolic syndrome in stone patients were significantly higher than those in general population. The number of 24-hour urinary abnormalities was positively associated with body mass index. The interventions on high urinary sodium, low urinary volume, obesity and metabolic syndrome were important to the treatment of urolithiasis. This database would facilitate the metabolic evaluation, provide evidence for the treatment and prevention of urolithiasis, and lay foundation for finding important controllable risk factors of urinary stone.

Clinicoradiological features associated with epidermal growth factor receptor exon 19 and 21 mutation in lung adenocarcinoma.

AIM: To retrospectively identify clinicopathological and radiological characteristics that could be independent predictors of epidermal growth factor receptor (EGFR) exon 19 and 21 mutation in surgically resected lung adenocarcinomas in a cohort of Asian patients. MATERIALS AND METHODS: Demographics, histopathology data, and preoperative chest computed tomography (CT) images were evaluated retrospectively in 471 surgically resected lung adenocarcinomas. A total of 24 CT descriptors were assessed. Univariate analyses and multivariate logistic regression analyses were performed to identify independent predicted factors of harbouring EGFR mutations. RESULTS: EGFR mutations were existed in 252 (53.5%) of 471 patients, and associated with 11 clinicoradiological features. For the model with both clinical and radiological features, the independent predictors of harbouring EGFR mutation were small maximum diameter (≤3.9 cm), non-smokers, micropapillary pattern, pleural retraction, vascular convergence, and absence of solid pattern. The area under the receiver operating characteristic (ROC) curve (AUC) was 0.784. Multivariable logistic regression analysis indicated that non-smokers, vascular convergence, and absence of solid pattern were important independent predictors of EGFR exon 19 mutation, while non-smokers and vascular convergence were independent predictors of EGFR exon 21 mutation. The AUCs were 0.807 and 0.794, respectively. A lepidic growth pattern appeared more frequently in exon 21 mutant tumours than in exon 19 mutant group (p<0.001). CONCLUSION: CT imaging features of lung adenocarcinomas in combination with clinical variables could be used to prognosticate EGFR mutation status. The separate analysis of EGFR exon 19 or 21 mutation could further improve diagnostic performance.

[Radiomics: the process and applications in tumor research].

Radiomics enables extraction of innumerable quantitative features from medical images with high-throughput computing for diagnosis and prediction. The practice of radiomics involves image acquisition, identifying and segmenting the volumes of interest, extracting and analyzing of quantitative features, and classification or prediction model development. Compared with traditional visual interpretation of medical images, the deep mining of medical images by computer technology from radiomics makes feature uptake more efficient, relatively objective and rich in feature types. Whereas, radiomic analysis requires high image quality and consistent scan parameters. The features extracted are confined to the segmented area. Radiomics is promising in tumor screening, early diagnosis, accurate grading and staging, treatment and prognosis, molecular characteristics and so on. Combined with traditional visual interpretation of medical images, radiomics is helpful in tumor diagnosis and prediction.

[Comparison of the diagnostic efficiency in breast malignancy between cone beam breast CT and mammography in dense breast].

Objective: To compare the diagnostic efficiency of lesion in dense breast between cone beam breast computer tomography (CBBCT) and mammography. Methods: From May 2012 to August 2014, 160 patients with 165 breasts who underwent mammography and CBBCT examinations were included in this study. The diagnostic results of CBBCT and mammography were reviewed and compared with pathological results. Results: In the 165 breast, 24 were dense breasts and 141 were dense breasts. The diagnostic results were similar in 109 lesions, but different in 56 lesions. According to the analysis of the 165 breasts using receiver operation characteristics (ROC) curve, the area under the ROC curves (AUC) of CBBCT and mammography were 0.923 (95%CI: 0.878-0.967, P<0.05) and 0.959 (95%CI: 0.926-0.992, P<0.05), respectively. With Breast Imaging-Reporting and Data System (BI-RADS) 4b as the critical value, the sensitivity and specificity were 70.0% and 98.7% using mammography, and 83.3% and 97.3% using CBBCT, respectively. The AUC of CBBCT and mammography of the 141 dense breasts was 0.919(95%CI: 0.868-0.969, P<0.05) and 0.973(95%CI: 0.947-0.999, P<0.05), respectively. With BI-RADS 4b as the critical value, the sensitivity and specificity were 69.0% and 98.6% by mammography, and 83.1% and 98.6% by CBBCT, respectively. Conclusions: CBBCT showed higher sensitivity and specificity in the diagnosis of breast malignant tumors compared to mammography. It is expected to be applied to breast cancer detection in the future, especially in dense breast.

EGb761 improves histological and functional recovery in rats with acute spinal cord contusion injury.

STUDY DESIGN: This is an experimental study. OBJECTIVES: The objective of this study was to evaluate the neuroprotective effects of Ginkgo biloba extract 761 (EGb761) on histological features of injured sites and on functional performance of rats subjected to standardized spinal cord injury (SCI). SETTING: This study was conducted in Xian, Shaanxi, China. METHODS: Thirty female Sprague-Dawley rats were randomly divided into three groups: sham-operated, saline-treated control and EGb761-treated. The Basso, Beattie, Bresnahan Locomotor Rating Score (BBB score) was calculated and footprint analysis was performed to evaluate the functional performance of the rats in each group. Hematoxylin and eosin (HE) staining and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and caspase-3 staining were performed to evaluate the necrosis area and apoptotic cells at the injured site in each group. RESULTS: At 14, but not 1, 3 and 7, days post injury (DPI), rats in the EGb761-treated group exhibited significantly better BBB scores compared with the saline-treated control group (P<0.05). The EGb761-treated group also showed increased stride length, decreased stride width and reduced toe dragging at 14 DPI (P<0.05). Analysis of HE staining revealed that the EGb761-treated group had reduced necrosis at the injury site compared with the saline-treated control group (P<0.05). Analysis of TUNEL and caspase-3 staining demonstrated that cell apoptosis was increased at 1-14 DPI, peaking at 24-h post injury in the gray matter, and 7 DPI in the white matter. At 7 DPI, the quantity of apoptotic cells was significantly decreased in the EGb761-treated group. CONCLUSION: EGb761 administration during the acute phase after SCI significantly reduced secondary injury-induced tissue necrosis and cell apoptosis and improved functional performance in rats.

PI3K-AKT pathway polymerase chain reaction (PCR) array analysis of epilepsy induced by type II focal cortical dysplasia.

The aims of this study were to observe the differential expression of PI3K-AKT pathway-related genes in seizure-inducing brain lesions in type II focal cortical dysplasia, and to explore the relationship between gene expression and histological changes in dysplastic foci and their epileptogenic mechanism. Typical lesions in brain tissue from three patients with epilepsy induced by type II focal cortical dysplasia were selected for analysis, along with normal brain tissue from two control group individuals. Following quantitative expression analysis using the RT2 Profiler(TM) PI3K-AKT PCR Array, differential expression of the pathway related genes was detected in the focal brain tissue lesions, and gene function queries were performed. Compared with the control group, thirteen related genes appeared to exhibit marked differences in expression in epileptic lesions from patients with type II focal cortical dysplasia; those genes were found to be involved in regulation of cell size, morphology, adhesion, migration, and apoptosis, and in immunity, inflammation, and many other domains. The differential expression of multiple genes in the PI3K-AKT signaling pathway in type II focal cortical dysplasia may be an important molecular mechanism underlying histological changes and recurrent seizures.

Seasonal variation and source apportionment of organic tracers in PM10 in Chengdu, China.

Organic compound tracers including n-alkanes, triterpane, sterane, polycyclic aromatic hydrocarbons (PAHs) and dicarboxylic acids of airborne particulate matter (PM10) were characterized for samples collected at five sites from July 2010 to March 2011 using GC/MS. Spatial and temporal variations of these organic tracers in PM10 were studied, and their sources were then identified respectively. Average daily concentrations of PM10 varied in different seasons with the trend of PM10 in winter (0.133 mg/m(3)) > autumn (0.120 mg/m(3)) > spring (0.103 mg/m(3)) > summer (0.098 mg/m(3)). Daily concentrations of n-alkanes (C11-C36) ranged from 12.11 to 163.58 ng/m(3) with a mean of 61.99 ng/m(3). The C max and CPI index of n-alkanes indicated that vehicle emissions were the major source in winter, while the contributions of high plant wax emissions became significant in other seasons. It was discovered that the main sources of triterpenoid and steranes were gasoline and diesel engine emissions. Concentrations of ∑15PAHs in PM10 also varied (12.25-58.56 ng/m(3)) in different seasons, and chrysene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(ghi) perylene and fluoranthene were the dominant components. In the four seasons, the concentration of ∑15PAHs was relatively higher at the northern site because of traffic congestion. The main source of airborne PAHs was traffic emissions and coal combustion. Average daily concentrations of dicarboxylic acids (C4-C10) in PM10 ranged from 12.11 to 163.58 ng/m(3), of which azeleic acid was the major compound (0.49-52.04 ng/m(3), average 14.93 ng/m(3)), followed by succinic acid (0.56-19.08 ng/m(3), average 6.84 ng/m(3)). The ratio of C6/C9 showed that the major source in winter was biological, while the contributions of emissions from anthropogenic activities were much higher in summer.

SiRNA-mediated knockdown against NUF2 suppresses tumor growth and induces cell apoptosis in human glioma cells.

Glioma is one of the most commonly malignant brain tumors. Current therapies for glioma have failed to achieve satisfactory results, which necessitates the development of novel molecular therapies. In the current study, we aimed to investigate the role of NUF2 (Ndc80 kinetochore complex component) in glioma cell growth and assessed the possible mechanisms underlying NUF2-mediated glioma development. The lentivirus-based short hairpin RNA-expressing vectors were constructed and transfected into U87 and U251 cells. Real time PCR and western blot were performed for expression level determination. Annexin V-FITC/PI flow cytometric assay was conducted to determine apoptotic cell proportions. Cell viability in vitro and tumorgenic ability in vivo were assessed by MTT assay and a nude mouse xenograft, respectively. We found that NUF2 was overexpressed in glioma tissues and differentially expressed in a series of glioma cell lines. Depletion of NUF2 by short-hairpin RNA inhibited cell growth in vitro and in vivo. Furthermore, NUF2 depletion-induced growth inhibition was associated with cell cycle arrest and apoptosis. Aberrant expressions of cell cycle regulators and apoptosis-related proteins further confirmed that NUF2 depletion induced cell cycle arrest and apoptosis. In all, our results indicate that siRNA-mediated knockdown against NUF2 may be a promising therapeutic method for the treatment of glioma.

High-dose ascorbic acid administration improves functional recovery in rats with spinal cord contusion injury.

OBJECTIVES: To evaluate the effects of different doses of ascorbic acid (AA) on the functional performance of rats subjected to standardized spinal cord injury (SCI). METHODS: Thirty female Sprague-Dawley rats were divided into three groups (10 animals in each group): control group: rats were subjected to SCI injury and received intraperitoneal saline administration; normal-dose AA group: rats were subjected to SCI injury and received daily intraperitoneal administration of AA at 100 mg kg(-1) bodyweight; high-dose AA group: rats were subjected to SCI injury and received daily intraperitoneal administration of AA at 200 mg kg(-1) bodyweight. The Basso, Beattie, Bresnahan Locomotor Rating Score (BBB score) and footprint analysis were performed to evaluate the functional performance of the rats in each group, and hematoxylin and eosin staining was performed to evaluate necrosis at the injury site. RESULTS: At days 14 and 28 after SCI, rats in the high-dose AA group, but not the normal-dose AA group, exhibited significantly better BBB score compared with the control group (P<0.05). Compared with the control and normal-dose AA group, the high-dose AA group also showed increased stride length, decreased stride width and reduced toe dragging (P<0.05). Histological analysis revealed that both the normal- and high-dose AA groups had reduced necrosis in the injury site compared with the control group (P<0.05). CONCLUSION: High-dose AA administration during the acute phase post SCI significantly reduced secondary injury-induced tissue necrosis and improved functional performance in rats.

CT features and quantification of the characteristics of adrenocortical carcinomas on unenhanced and contrast-enhanced studies.

AIM: To describe the morphological and contrast-agent washout characteristics of adrenocortical carcinomas (ACCs) on computed tomography (CT). MATERIALS AND METHODS: Forty-one patients with histopathologically proven ACCs were retrospectively evaluated. The morphological characteristics of the ACCs were documented and compared with surgical and histopathological findings. The percentage of contrast agent enhancement washout (PEW) and relative PEW (RPEW) were calculated for 17 patients who had the combination of unenhanced, portal venous, and 15 min delayed phase images. RESULTS: Characteristic imaging findings of ACCs included large size (38 of 41 tumours were >6 cm), well-defined margin with a thin enhancing rim (25 patients), and central stellate area of low attenuation on contrast-enhanced CT images (21 patients). Tumour extension into the inferior vena cava (IVC) with associated thrombus was identified on CT in six (14.6%) patients. Of 17 tumours evaluated, 12 (71%) had a PEW value of ≤60%, and 14 (82%) had an RPEW value of ≤40%. CONCLUSION: Large size, a well-defined margin with a thin enhancing rim, central low attenuation, and a predilection for extension into the IVC are typical morphological characteristics of ACC on CT. The contrast-washout characteristics of ACCs, in concordance with their malignant nature, share those of non-adenomas rather than adenomas.

Transzygomatic approach for the resection of large condylar osteochondromas using computer-assisted preoperative planning.

The purpose of this study was to evaluate the outcomes of patients with large osteochondromas (OCs) treated via transzygomatic approach for exposure and local resection. All patients with large OCs treated by transzygomatic approach from 2006 through 2014 were investigated. The inclusion criteria were (1) condylar OC of exogenous type; (2) a mass that could be treated only via transzygomatic approach, as assessed using computer-assisted preoperative planning. The preliminary results evaluated included recurrence, joint form and function, occurrence of facial deformity, facial nerve function, and the condition of the zygomatic arch fixation. Other parameters assessed included tumour size and location and the length of follow-up. Ten patients with OCs were included in this study. All masses were located anteromedial to the condyle; the average maximal diameter was 33.15mm. During follow-up (average 28.5 months), the average maximum inter-incisal opening increased from 25.4mm to 32.0mm. Nine patients recovered without recurrence, a change in occlusion, secondary deformity, or nerve dysfunction. One patient had severe disc perforation and condylar resorption. The transzygomatic approach is applicable for the resection of large condylar OCs protruding anteromedially into the infratemporal space. Surgical simulations may help to identify the indications for this approach and to design the surgery.

A novel approach to neoplasms medial to the condyle: a condylectomy with anterior displacement of the condyle.

Resecting neoplasms involving the infratemporal space has a high risk of damaging critical nerves and vessels, in addition to joint form and function. The purpose of this study was to introduce a novel approach to lesions medial to the condyle, which comprises a condylectomy with anterior displacement of the condyle. The indications evaluated using digital surgical simulation, the critical surgical technique, and the preliminary clinical effects are presented here. Five cases underwent this approach between January 2006 and December 2014. The common characteristics of the five masses were (1) that they were non-malignant neoplasms involving the posterior-medial region of the condyle; (2) the upper and lower borders were between the skull base and the lingula, while the anterior border did not exceed the coronoid process. All masses were resected successfully with no damage to any critical nerves or vessels. The average follow-up period was 29.8 months (range 6-56 months). There was no recurrence, secondary deformity, or facial paralysis. The average mouth opening improved from an original 27 mm to 34 mm after surgery. The condyles were well fixed, with no resorption, as shown on computed tomography scans.

[The prevalence of temporomandibular disorder symptoms in 898 university students and its relationship with psychological distress and sleep quality].

OBJECTIVE: To investigate the prevalence of temporomandibular disorders(TMD) symptoms, psychological distress and sleep quality in a population of Chinese university students, and discuss the relationship between psychological distress, sleep quality and TMD symptoms. METHODS: A total of 898 stomatological university students from 5 Chinese universities(342 males and 556 females with a mean age of 20.5 years) were included in the study. Self-reported TMD symptoms using diagnostic criteria for temporomandibular disorders symptom questionnaire were collected. Depression, anxiety and stress scales-21(DASS-21) and Pittsburgh sleep quality index(PSQI) were used to measure psychological distress and sleep quality. RESULTS: 61.9% (556/898) of the students had TMD symptoms. The most common symptoms were pain and clicking of joint, with a prevalence of 42.3% (380/898) and 34.2% (307/898), respectively. The prevalence of depression, anxiety, stress and sleep quality among the students who had TMD symptoms was 33.5%(186/556), 63.1%(351/556), 29.5%(164/556) and 30.2%(243/556), respectively, which was significantly higher than those who had no TMD symptoms(24.3% [83/342], 48.5% [166/342], 21.6%[74/342] and 21.9%[75/342])(P<0.05). Stepwise logistic regression analysis demonstrated that anxiety (OR 1.57, 95%CI 1.14-2.15) and female(OR 1.57, 95%CI 1.19-2.08) were possible risk indicators for TMD symptoms(P<0.05). CONCLUSIONS: Chinese university students reported a high prevalence of TMD symptoms, which may have a correlation with psychological distress symptoms such as anxiety.

Mechanisms of total lymphoid irradiation-induced immunosuppression. II. Failure of con A-stimulated splenocytes from TLI-treated mice to express IL-2 and IL-2 receptor RNA.

Total lymphoid irradiation is a radiotherapy procedure used as an alternative immunosuppressive regimen in organ transplantation. Following TLI mature lymphocytes are depleted, and splenocytes do not proliferate to mitogens, produce IL-2, or express IL-2 receptors. We now show that mitogen stimulated splenocytes from TLI-treated mice do not secrete IL-2 protein by an IL-2 ELISA assay. Northern blot analysis and RNase protection assays reveal that TLI splenocytes do not make IL-2 RNA or IL-2 receptor RNA following mitogen stimulation. TLI splenocytes produce at least 1000 times less IL-2 RNA after Con A stimulation than normal splenocytes. TLI therapy resembles anti-CD4 therapy and CsA in that each results in an IL-2-"depleted" state.

[Study of cardiovascular and cerebrovascular disease in Chinese traditional medicines on Pb, Cr, Cd by AAS].

Cardiovascular and cerebrovascular disease are the common and frequently-occurring disease for the old man and are the main cause of death in the world. The Z-8000 polarized zeeman atomic absorption spectrophotometer was used for the determination of Pb, Cr, Cd in seventeen kinds of Chinese traditional medicines. And studied on Pb, Cr, Cd in Zhennao Ning, Di Ao Xinxue Kang, Linao Xin, Xueshuan Xinmai Ning et al. thirteen kinds of Chinese traditional medicines. The result shows that Chinese traditional medicines of cardiovascular and cerebrovascular drugs contain Pb, Cr, Cd and their efficacies are related to Pb, Cr, Cd.

Vascular stiffness in familial hypercholesterolaemia is associated with C-reactive protein and cholesterol burden.

BACKGROUND: Familial hypercholesterolaemia (FH) is characterized by very high serum cholesterol and premature coronary atherosclerosis. Arterial stiffness and atherosclerosis are two major underlying pathophysiologies of arterial disease that are predictive of future cardiovascular events. The aims of this study were to quantify atherosclerosis and arterial stiffness and to evaluate their relationship with high sensitive C-reactive protein (hs-CRP) and the level of exposure to high serum cholesterol in FH patients. MATERIALS AND METHODS: We measured traditional risk factors, hs-CRP, intima-media thickness (IMT) of carotid artery, and brachial-ankle pulse wave velocity (baPWV) in 35 heterozygous FH subjects and 17 healthy control subjects. Cholesterol-year score (CYS) was calculated to estimate the lifetime cholesterol burden in FH subjects. RESULTS: FH subjects had significantly elevated total cholesterol, low-density lipoprotein cholesterol, and carotid IMT compared with those without mutations. Among FH patients, the baPWV and carotid IMT were higher in cases with high cholesterol burden than those without. Similarly, the baPWV and carotid IMT were also higher in cases with elevated hs-CRP (> 1 mg L(-1)) than those without. Multiple linear regression analysis demonstrated CYS and hs-CRP were significant independent predictors of baPWV and IMT in FH patients. CONCLUSIONS: Both high cholesterol burden and vascular inflammation are not only associated with atherosclerosis, but also contribute to the development of arterial stiffness in FH patients. Early detection of hypercholesterolaemia in FH patients is warranted to prevent the untoward pathophysiologies.

Identification and characterization of novel low-density lipoprotein receptor mutations of familial hypercholesterolaemia patients in Taiwan.

BACKGROUND: Familial hypercholesterolaemia (FH) is an autosomal dominant disease associated with a very high risk of coronary vascular disease. The study objective was to identify patients with FH in Taiwan and characterize novel mutations. MATERIALS AND METHODS: Fifty-one patients with suspected FH living in Taiwan were screened for mutations in both the low-density lipoprotein (LDL) receptor and the apolipoprotein (apoB) genes using the multiplex polymerase chain reaction and exon-by-exon DNA sequencing technique. Functional consequences on LDL receptor activity were characterized in vitro for novel mutations and family pedigree was also analyzed. RESULTS: Thirteen different functional mutations in the LDL receptor gene and one mutation in the apoB gene were found in 21 patients. Among the 13 mutations in the LDL receptor gene, 10 were single-point missense mutations, one was a two-point mutation in the same allele, one was a non-sense mutation and one was a frame-shift mutation. There were three novel mutations, including two missense mutations (M510K and W512R) and one frame-shift mutation (1953 delTA mutation). The characterization of missense M510K retained 36.2% of the activity of the normal receptor. Conversely, frame-shift 1953 delTA and missense W512R led to defective proteins, with only 0-6% of normal receptor activity. CONCLUSIONS: The study identified 13 LDL receptor gene mutations and characterized three novel mutations causing FH in Taiwan. This facilitated a better understanding of FH among the Chinese population and may enable diagnosis of FH at the molecular level at a presymptomatic, early age.

Mechanisms of tolerance induction: splenocytes from total lymphoid irradiated mice inhibit the IL-2 pathway in TCR-activated CD4 cells.

Mice given total lymphoid irradiation (TLI) can be tolerized by an incompletely understood mechanism to foreign Ags given during a brief window of time immediately after completing radiation. We previously showed that splenocytes taken from mice immediately after completing TLI treatment (TLI cells) block the ability of control cells to proliferate or to produce IL-2 in response to alloantigen, suggesting that TLI cells interfere with the IL-2 pathway in responder lymphocytes. To further characterize the mechanism by which TLI cells affect IL-2, we utilized an in vitro system of T cell activation. Adding TLI cells into cultures decreased the ability of TCR-stimulated T cells to proliferate and to secrete IL-2 by 40 to 60%. Exogenous IL-2 did not restore the proliferative response. The inhibition of IL-2 secretion resulted both from a decrease in the number of IL-2-producing cells and a decrease in IL-2 mRNA transcription. TLI cells directly inhibited IL-2 secretion by TCR-stimulated CD4 cells, as determined by ELISPOT. Competitive PCR demonstrated that TLI cells decreased IL-2 transcription of TCR-stimulated CD4 cells by 75%. In situ hybridization confirmed that unfractionated spleen and sorted CD4 cells from TCR-stimulated cultures transcribed less IL-2 RNA in the presence of TLI cells. The results show that TLI cells directly inhibit IL-2 transcription and protein secretion of normal TCR-stimulated CD4 cells.