Performance of a new quantitative computed tomography index for interstitial lung disease assessment in systemic sclerosis.

Quantitative high resolution computed tomography (HRCT) may objectively assess systemic sclerosis (SSc)-interstitial lung disease (ILD) extent, using three basic densitometric measures: mean lung attenuation (MLA), skewness, and kurtosis. This prospective study aimed to develop a composite index - computerized integrated index (CII) - that accounted for MLA, skewness, and kurtosis by means of Principal Component Analysis over HRCTs of 83 consecutive SSc subjects, thus eliminating redundancies. Correlations among CII, cardiopulmonary function and immune-inflammatory biomarkers (e.g. sIL-2Rα and CCL18 serum levels) were explored. ILD was detected in 47% of patients at visual HRCT assessment. These patients had worse CII values than patients without ILD. The CII correlated with lung function at both baseline and follow-up, and with sIL-2Rα and CCL18 serum levels. The best discriminating CII value for ILD was 0.1966 (AUC = 0.77; sensitivity = 0.81 [95%CI:0.68-0.92]; specificity = 0.66 [95%CI:0.52-0.80]). Thirty-four percent of patients without visual trace of ILD had a CII lower than 0.1966, and 67% of them had a diffusing lung capacity for CO <80% of predicted. We showed that this new composite CT index for SSc-ILD assessment correlates with both lung function and immune-inflammatory parameters and could be sufficiently sensitive for capturing early lung density changes in visually ILD-free patients.

GOF/LOF knowledge inference with tensor decomposition in support of high order link discovery for gene, mutation and disease.

For discovery of new usage of drugs, the function type of their target genes plays an important role, and the hypothesis of "Antagonist-GOF" and "Agonist-LOF" has laid a solid foundation for supporting drug repurposing. In this research, an active gene annotation corpus was used as training data to predict the gain-of-function or loss-of-function or unknown character of each human gene after variation events. Unlike the design of(entity, predicate, entity) triples in a traditional three way tensor, a four way and a five way tensor, GMFD-/GMAFD-tensor, were designed to represent higher order links among or among part of these entities: genes(G), mutations(M), functions(F), diseases( D) and annotation labels(A). A tensor decomposition algorithm, CP decomposition, was applied to the higher order tensor and to unveil the correlation among entities. Meanwhile, a state-of-the-art baseline tensor decomposition algorithm, RESCAL, was carried on the three way tensor as a comparing method. The result showed that CP decomposition on higher order tensor performed better than RESCAL on traditional three way tensor in recovering masked data and making predictions. In addition, The four way tensor was proved to be the best format for our issue. At the end, a case study reproducing two disease-gene-drug links(Myelodysplatic Syndromes-IL2RA-Aldesleukin, Lymphoma- IL2RA-Aldesleukin) presented the feasibility of our prediction model for drug repurposing.

[Clinical significance of detection of soluble interleukin 2 receptor alpha chain in the assessment of rheumatoid arthritis disease activity].

OBJECTIVE: To evaluate soluble interleukin-2 receptor alpha chain (sIL-2Rα, sCD25) in serum for the determination of rheumatoid arthritis (RA) activity. METHODS: Peripheral blood was collected from 108 patients with RA, 39 patients with osteoarthritis (OA) and 50 healthy control subjects, and synovial fluids were from 40 patients with RA. The sera from the patients with RA, the disease control group (osteoarthritis), the healthy control group, and the synovial fluids of the RA patients were detected by enzyme-linked immunosorbent assay (ELISA).The clinical manifestations and laboratory parameters of the patients with RA were recorded and the correlation with the serum sCD25 level was analyzed. RESULTS: The serum sCD25 concentration in RA group was (2 886±1 333) ng/L, the serum sCD25 concentration in OA group was (2 090±718) ng/L, and the serum sCD25 concentration in healthy group was (1 768±753) ng/L. The serum sCD25 level in the patients with RA was significantly higher than that in the disease controls and healthy controls (P<0.001). Sensitivity of serum sCD25 in the diagnosis of RA was 66.1% and specificity was 83.0%;serum sCD25 levels and erythrocyte sedimentation rate (r=0.321, P=0.001), C-reactive protein (r=0.446, P<0.001), DAS28 score (r=0.324, P<0.001), joint tenderness count (r=0.203, P=0.024), D-dimer levels (r=0.383, P<0.001), age (r=0.24, P=0.007), IgG (r=0.207, P=0.028), HRF-IgG (r=0.345, P=0.034) showed a significant positive correlation, and disease duration (r=-0.206, P=0.021) showed a negative correlation with sCD25;In patients with rheumatoid arthritis, the positive rates of serum ESR, CRP, and sCD25 were 14.3% (2 cases), 14.3% (2 cases), and 71.4% (10 cases) in the low disease activity group. The positive rates of serum ESR, CRP and sCD25 in the moderate disease activity group were 94.2% (49 cases), 82.7% (43 cases), and 86.5% (45 cases). The positive rates of serum ESR, CRP, and sCD25 in the high disease activity group were 100% (42 cases), 95.2% (40 cases), and 90.5% (38 cases);36 cases of ESR and/or CRP were negative (about 33.3%) in 108 patients, serum sCD5 levels of 17 cases in these 36 cases (about 47.2%)increased, of which 14 cases (about 82.4%) had a DAS28 score higher than 3.2. CONCLUSION: The serum sCD25 has a high specificity for diagnosis of RA and a poor sensitivity. The serum level is closely related to the activity of RA, indicating that sCD25 may be involved in the inflammatory process of RA and may become a new inflammatory marker of RA. It is more meaningful for detection of serum sCD25 when RA is active, but ESR and/or CRP is negative.

In vitro assessment of cord blood-derived proinsulin-specific regulatory T cells for cellular therapy in type 1 diabetes.

BACKGROUND: Antigen-specific regulatory T cells (Tregs) have proven to be effective in reversing established autoimmunity in type 1 diabetes (T1D). Cord blood (CB) can serve as an efficient and safe source for Tregs for antigen-specific immunomodulation in T1D, a strategy that is yet to be explored. Therefore, we assessed the potential of CB in generation of proinsulin (PI)-specific Tregs by using HLA class II tetramers. METHODS: We analyzed the frequency of PI-specific natural Tregs (nTregs) and induced Tregs (iTregs) derived from the CB as well as peripheral blood (PB) of patients with T1D and healthy control subjects. For this, CD4+CD25+CD127low and CD4+CD25-T cells were cultured in the presence of PI-derived peptides, transforming growth factor (TGF)-ß and rapamycin. PI-specific Tregs were then selected using allele-specific HLA II tetramers loaded with PI-derived peptides, followed by suppression assays. RESULTS: Following stimulation, we observed that CB harbors a significantly higher frequency of PI-specific Tregs than PB of subjects with T1D (P = 0.0003). Further, the proportion of PI-specific Tregs was significantly higher in both the nTreg (P = 0.01) and iTreg (P = 0.0003) compartments of CB as compared with PB of subjects with T1D. In co-culture experiments, the PI-specific Tregs suppressed the proliferation of effector T cells significantly (P = 0.0006). The expanded nTregs were able to retain hypomethylation status at their Tregs-specific demethylated region (TSDR), whereas iTregs were unable to acquire the characteristic demethylation pattern. CONCLUSION: Our study demonstrates that CB can serve as an excellent source for generation of functional antigen-specific Tregs for immunotherapeutic approaches in subjects with T1D.

HLA Class Ia and Ib Polyreactive Anti-HLA-E IgG2a Monoclonal Antibodies (TFL-006 and TFL-007) Suppress Anti-HLA IgG Production by CD19+ B Cells and Proliferation of CD4+ T Cells While Upregulating Tregs.

The anti-HLA-E IgG2a mAbs, TFL-006 and TFL-007, reacted with all HLA-I antigens, similar to the therapeutic preparations of IVIg. Indeed, IVIg lost its HLA reactivity, when its HLA-E reactivity was adsorbed out. US-FDA approved IVIg to reduce antibodies in autoimmune diseases. But the mechanism underlying IVIg-mediated antibody reduction could not be ascertained due to the presence of other polyclonal antibodies. In spite of it, the cost prohibitive high or low IVIg is administered to patients waiting for donor organ and for allograft recipients for lowering antiallograft antibodies. A mAb that could mimic IVIg in lowering Abs, with defined mechanism of action, would be highly beneficial for patients. Demonstrably, the anti-HLA-E mAbs mimicked several functions of IVIg relevant to suppressing the antiallograft Abs. The mAbs suppressed activated T cells and anti-HLA antibody production by activated B cells, which were dose-wise superior to IVIg. The anti-HLA-E mAb expanded CD4+, CD25+, and Foxp3+ Tregs, which are known to suppress T and B cells involved in antibody production. These defined functions of the anti-HLA-E IgG2a mAbs at a level superior to IVIg encourage developing their humanized version to lower antibodies in allograft recipients, to promote graft survival, and to control autoimmune diseases.

Cost-Effectiveness of Antibody-Based Induction Therapy in Deceased Donor Kidney Transplantation in the United States.

BACKGROUND: Induction therapy in deceased donor kidney transplantation is costly, with wide discrepancy in utilization and a limited evidence base, particularly regarding cost-effectiveness. METHODS: We linked the United States Renal Data System data set to Medicare claims to estimate cumulative costs, graft survival, and incremental cost-effectiveness ratio (ICER - cost per additional year of graft survival) within 3 years of transplantation in 19 450 deceased donor kidney transplantation recipients with Medicare as primary payer from 2000 to 2008. We divided the study cohort into high-risk (age > 60 years, panel-reactive antibody > 20%, African American race, Kidney Donor Profile Index > 50%, cold ischemia time > 24 hours) and low-risk (not having any risk factors, comprising approximately 15% of the cohort). After the elimination of dominated options, we estimated expected ICER among induction categories: no-induction, alemtuzumab, rabbit antithymocyte globulin (r-ATG), and interleukin-2 receptor-antagonist. RESULTS: No-induction was the least effective and most costly option in both risk groups. Depletional antibodies (r-ATG and alemtuzumab) were more cost-effective across all willingness-to-pay thresholds in the low-risk group. For the high-risk group and its subcategories, the ICER was very sensitive to the graft survival; overall both depletional antibodies were more cost-effective, mainly for higher willingness to pay threshold (US $100 000 and US $150 000). Rabbit ATG appears to achieve excellent cost-effectiveness acceptability curves (80% of the recipients) in both risk groups at US $50 000 threshold (except age > 60 years). In addition, only r-ATG was associated with graft survival benefit over no-induction category (hazard ratio, 0.91; 95% confidence interval, 0.84-0.99) in a multivariable Cox regression analysis. CONCLUSIONS: Antibody-based induction appears to offer substantial advantages in both cost and outcome compared with no-induction. Overall, depletional induction (preferably r-ATG) appears to offer the greatest benefits.

Assessment of the Effects of Rituximab Monotherapy on Different Subsets of Circulating T-Regulatory Cells and Clinical Disease Severity in Severe Pemphigus Vulgaris.

BACKGROUND: Robust evidence for the efficacy of rituximab monotherapy in pemphigus is lacking. The effects of rituximab on T-regulatory cells (Tregs) in pemphigus have not been studied. OBJECTIVE: The primary objective was to assess the efficacy of rituximab monotherapy in severe pemphigus vulgaris. The secondary objectives were to assess whether counts of different subsets of Tregs in the peripheral blood correlate with baseline clinical severity and whether clinical response in severe pemphigus is associated with an alteration in the Treg count. METHODS: Eighteen eligible subjects with severe pemphigus vulgaris were recruited and were treated with 1 g of intravenous rituximab on days 0 and 15. Efficacy was assessed in terms of disease control, time to disease control, complete remission off therapy, and relapse. Flow cytometric analysis of CD4+CD25+FoxP3, IL-10-secreting Tr1, and TGF-ß secreting Th3 regulatory cells was performed. Clinical evaluation and flow cytometric analysis of Tregs was performed periodically until follow-up at 26 weeks. RESULTS: Rituximab monotherapy was able to induce complete remission in all but 5 (68.75%) patients and was well tolerated. No direct relationship between clinical severity and CD4+CD25+FoxP3 cell counts was found. There were inverse correlations between serially measured values of the cutaneous and mucosal Autoimmune Bullous Skin Disorder Intensity Score (ABSIS) and Th3 cell count. CONCLUSION: Rituximab is a safe and effective monotherapy option for severe pemphigus. As the immunological findings were somewhat different from those observed in other autoimmune conditions treated with rituximab, further studies are required to substantiate the findings of our study in pemphigus patients.

Assessment of Immunological Biomarkers in the First Year after Heart Transplantation.

BACKGROUND: Pharmacodynamic biomarkers that detect changes of immunological functions have been recognized as a helpful tool to increase the efficacy of immunosuppressive drug therapies. However, physiological changes of immunological biomarkers following transplantation are not investigated. Therefore, we assessed frequently used immunological biomarkers of the circulating blood in the first year following heart transplantation (HTx). METHODS: Activation markers CD25 and CD95, intracellular cytokines IL-2 and IFNγ, chemokines IP10 and MIG, and subsets of dendritic cells as well as antibodies against human leukocyte antigens (HLA) and major histocompatibility complex class I-related chain A (MICA) antigens were analyzed at different time points using flow cytometry and Luminex xMAP technology. RESULTS: Expression of IL-2, IFNγ, and plasmacytoid dendritic cells (pDCs) significantly increased (p < 0.01) during the first year. Anti-HLA antibodies decreased continuously, while anti-MICA antibodies showed minor increase within the first year. An association between percentage of pDCs and anti-MICA antibody positivity was proven. pDCs, IFNγ-producing T cells, and IP10 concentration were associated in a stronger way with age and gender of HTx recipients than with antibodies against HLA or MICA. CONCLUSIONS: We conclude that certain immunological biomarkers of the circulating blood change during the first year after HTx. These changes should be considered for interpretation of biomarkers after transplantation.

Insight into normal thymic activity by assessment of peripheral blood samples.

The thymus is a highly specialized organ for T cell receptor (TCR) rearrangement and selection mechanisms that ensure the formation of functional and self-tolerant cells. Little is known about how peripheral blood assessment of thymic function reflects thymus activity during infancy. We compared thymic function-related markers in the thymus with those in peripheral blood in order to check their correlations. We concomitantly blood samples from immunocompetent infants who underwent cardiac surgery that involved thymectomy. The studied thymic markers included TCR excision circles (TRECs), four different TCRD (TCR delta chain) gene rearrangements, the TCR repertoire, regulatory T cells (Tregs, defined as the CD4+CD25+FOXP3+ cell population) and real-time quantitative polymerase chain reaction (RQ-PCR) mRNA expression of forkhead box P3 (FOXP3). Twenty patients were enrolled in this study. Their mean age at the time of the surgery was 3 months/5 days ± 3 months/18 days. There was a significant correlation between thymic and peripheral blood levels of TREC, all four TCRD gene rearrangements and the amount of Tregs. The levels of these parameters were significantly higher in the thymus than those detected in the peripheral blood. The TCR repertoire distribution in both samples was similar. FOXP3 mRNA levels in the thymus and peripheral blood correlated well. Our findings demonstrated a strong and significant correlation between peripheral blood and intra-thymic activity parameters during infancy. Assessment of these parameters in peripheral blood can be used to accurately estimate different intra-thymic capacities for assessing T cell function in health and disease.

A clinicopathologic study of 24 cases of systemic mastocytosis involving the gastrointestinal tract and assessment of mucosal mast cell density in irritable bowel syndrome and asymptomatic patients.

Counting mast cells in gastrointestinal (GI) mucosal biopsies is becoming an increasingly common practice. The primary reason for this exercise is to evaluate for possible involvement by systemic mastocytosis (SM). However, the features of mastocytosis in GI biopsies are not well described. In addition, recent studies have suggested that increased mast cells may be involved in the pathogenesis of some cases of diarrhea-predominant irritable bowel syndrome (IBS); the term "mastocytic enterocolitis" has been proposed for such cases. As the baseline mast cell density in colonic biopsies from normal patients has not been established in large cohorts, there is no widely accepted threshold for what constitutes increased mucosal mast cells. The aims of this study were (1) to determine the utility of GI biopsies for the diagnosis of SM, (2) to characterize the clinical, histologic, and immunohistochemical features of mastocytosis in the GI tract, (3) to determine mast cell density in normal colonic mucosa from a large cohort of asymptomatic patients, and (4) to compare these findings with those from patients with diarrhea-predominant IBS. Twenty-four patients with SM involving the GI tract, 100 asymptomatic patients, and 100 patients with IBS (the latter 2 groups with histologically normal colonic biopsies) were included. For the mastocytosis group, 107 biopsies (70 involved by mastocytosis; 67 mucosal, 3 liver) from 20 women and 4 men were evaluated (median age 59 y). The most commonly involved site was the colon (19 patients, 95%), followed by ileum (86%), duodenum (80%), and stomach (54%). In 16 cases (67%), the first diagnosis of SM was made on the basis of GI biopsies. Seventeen patients had documented cutaneous mastocytosis. Fifteen of 17 patients who underwent bone marrow biopsy had marrow involvement by SM. Eighteen patients had indolent disease, and 6 had aggressive disease (including all 3 with liver involvement). The most common GI symptom was diarrhea, followed by abdominal pain, nausea, weight loss, bloating, vomiting, or reflux. Liver disease presented with hepatomegaly and ascites. Endoscopic abnormalities (observed in 62%) included erythema, granularity, and nodules. Histologically, involved biopsies were characterized by infiltrates of ovoid to spindle-shaped mast cells in aggregates or sheets in the lamina propria, sometimes forming a confluent band underneath the surface epithelium; 25% of biopsies had only focal involvement (single aggregate). Prominent eosinophils were seen in 44% of involved colonic/ileal biopsies and 16% of duodenal biopsies. Mast cells were highlighted by diffuse membranous staining for KIT and CD25. In the nonmastocytosis groups, all biopsies contained singly dispersed mast cells with no aggregates. The mean highest mast cell counts (in a single high-power field) for asymptomatic patients and IBS patients were 26 (range, 11 to 55) and 30 (range, 13 to 59), respectively. In summary, GI (especially colonic) biopsies can establish a diagnosis of SM in patients with GI symptoms. GI involvement is usually subtle and is often associated with prominent eosinophils, which may obscure the mast cell infiltrate. KIT and CD25 are invaluable markers for the diagnosis. Mast cell density in colonic mucosa from asymptomatic patients is highly variable. Although patients with diarrhea-predominant IBS on average have mildly increased mast cells, the overlap in range with that of control patients is too great for this difference to be clinically useful. These findings argue against the utility of counting GI mucosal mast cell in patients with chronic diarrhea.

CD4+CD25+CD127- assessment as a surrogate phenotype for FOXP3+ regulatory T cells in HIV-1 infected viremic and aviremic subjects.

BACKGROUND: Although likely pivotal, the role of regulatory T cells (Tregs) in HIV pathogenesis remains elusive. This can be partly explained by analytical issues regarding their phenotypic identification in clinical studies. Instead of intracellular FOXP3 staining, CD4+CD25+CD127- phenotype has been proposed as an alternative to identify Tregs in clinical samples. However, its use remains controversial in viremic patients. Therefore, the objective of the present study was to assess the correlation between frequencies of CD4+CD25+CD127- and CD4+CD25+FOXP3+ lymphocytes in viremic and matched aviremic HIV-infected patients. METHODS: Peripheral blood was collected from HIV-1 infected patients. Eleven viremic patients (Viral Load > 40 copies/mL) were matched (age, sex, CD4+ cell number) with 8 aviremic patients under highly active antiretroviral therapy (HAART). Fresh whole blood was immediately stained to analyze by flow cytometry the correlation between CD4+CD25+CD127- and the reference phenotype CD4+CD25+FOXP3+ lymphocytes in the same tube (four color staining CD4/CD25/CD127/FOXP3 for concomitant analysis of cell surface and intracellular markers). RESULTS: In both groups, no significant differences were observed when comparing CD4+CD25+CD127- and CD4+CD25+FOXP3+ cell frequencies. In line, a strong correlation between CD4+CD25+CD127- and CD4+CD25+FOXP3+ lymphocyte percentages was observed in the whole patient population (r: 0.948, P < 0.001) or each group separately: aviremic (r: 0.968, P < 0.001), viremic (r: 0.9, P < 0.001). Finally, we found that most CD4+FOXP3+ cells were indeed CD25+CD127-, both in viremic and aviremic groups (88.5% and 90.9%, respectively). CONCLUSIONS: We observed that CD4+CD25+CD127- phenotype is a good and easy-to-perform surrogate identification strategy for FOXP3+ regulatory T cells in both viremic and aviremic HIV-1-infected subjects. Thus, it represents a useful tool for monitoring Tregs in clinical research studies based on large cohorts of patients prospectively monitored, including HIV-infected subjects.

Flow cytometric immunophenotyping of regulatory T cells in chronic lymphocytic leukemia: comparative assessment of various markers and use of novel antibody panel with CD127 as alternative to transcription factor FoxP3.

This study analyzed the frequency of regulatory T cells (Tregs) in chronic lymphocytic leukemia (CLL) by multiparameter flow cytometric immunophenotyping. Patients showed significantly increased frequencies of Tregs as compared to controls, a significantly higher percentage than that identified by previous studies, possibly indicating a different prognosis of CLL in different parts of the world and, more precisely, a worse prognosis of CLL in the Indian population. A higher frequency of Tregs was also seen in advanced stage of disease with significantly reduced frequencies of Tregs in patients with CLL after chemotherapy. A significant proportion of CD127low/-FoxP3+ Tregs expressed only low levels of CD25. Thus, CD127 appears to be a better marker than CD25 for the identification of CD4+FoxP3+ T cells as potential Tregs. Our results suggest that the specificity and sensitivity of CD4+CD127low/- cells are comparable to those of CD4+FoxP3+, which is the gold standard, and can be used as an alternative. This novel flow cytometric antibody panel with fewer number of antibodies is cost-effective and can be used to enumerate Tregs in resource-limited settings.

Immune dysregulation in chronic stress: a quantitative and functional assessment of regulatory T cells.

OBJECTIVE: Chronic stress is closely related to immune dysfunction. Immune parameters have been analyzed in many ways in humans and animals under chronic stress. Recently, it has been proved that FoxP3+ regulatory T cells (Tregs) play a key role in immune regulation in vivo. However, it has not yet been elucidated how Tregs respond to chronic stress in vivo. Therefore, in the present study, we investigated the frequency of and functional changes in Tregs from mice under chronic stress. METHODS: Spleen cells were separated from C57/BL6 mice that had been exposed to immobilization stress for 3 weeks. The frequencies of FoxP3+ and CD4+ CD25+ cells were analyzed by flow cytometry. CD4+CD25- cells (effector T cells, Teffs), CD4+CD25+ cells (Tregs) and CD4- cells (antigen-presenting cells, APCs) were separated for the functional assessment of the proliferative activity of Teffs, the suppressive activity of Tregs and the feeder activity of APCs. RESULTS: The results showed that chronic immobilization stress significantly increased the frequencies of CD4+CD25+ and CD4+FoxP3+ cells. Chronic immobilization stress also enhanced the suppressive function of CD4+ CD25+ Tregs. On the other hand, the proliferative activity of Teffs and the feeder activity of APCs were decreased in the mice under chronic immobilization stress. CONCLUSION: Taken together, it is suggested that increased number and function of Tregs may actively contribute to the immune dysfunction in chronic immobilization stress, synergizing with the decreased function of Teffs and APCs.

Comparative approach to define increased regulatory T cells in different cancer subtypes by combined assessment of CD127 and FOXP3.

In recent years an increase of functional CD4(+)CD25(+) regulatory T cells (T(reg) cells) has been established for patients with solid tumors, acute leukemias, and lymphomas. We have reported an expanded pool of CD4(+)CD25(high) T(reg) cells in patients with chronic lymphatic leukemia (CLL), multiple myeloma (MM) as well as its premalignant precursor monoclonal gammopathy of undetermined significance (MGUS). In healthy individuals, low-level expression of CD127 on T cells in addition to the expression of FOXP3 has been associated with T(reg) cells. Here, we demonstrate that the expanded FOXP3(+) T-cell population in patients with colorectal cancer, CLL, MGUS, MM, follicular lymphoma, and Hodgkin's disease are exclusively CD127(low) T(reg) cells and were strongly suppressive. A significant portion of CD127(low)FOXP3(+) T(reg) cells expressed only low levels of CD25 suggesting that the previously reported expansion of CD25(+) T(reg) cells underestimates the true expansion. The assessment of CCR7 and CD45RA expression on the expanded CD4(+)CD127(low)FOXP3(+) T(reg) cells revealed an increase of both naïve as well as central and effector memory T(reg) cells in peripheral blood. Our data strongly support superiority of combined CD127 and FOXP3 analysis in comparison to CD25 and FOXP3 assessment for further quantification of T(reg) cells in malignant diseases.

Non-random distribution of interleukin receptors on the cell surface.

Spatial organization of cell surface proteins plays a key role in the process of transmembrane signalling. Receptor clustering and changes in their cell surface distribution are often determining factors in the final outcome of ligand-receptor interactions. There are several techniques for assessing the distribution of protein molecules. Fluorescence resonance energy transfer (FRET) is an excellent tool for determining distance relationships of cell surface molecules. However, it does not provide information on the distribution of molecular clusters. Different kinds of microscopies fill this gap. The evaluation of the images provided by the listed techniques is often questionable. Herein we show the applicability of Ripley's K(t) function as a tool for analyzing the cell surface receptor patterns (Y. Nakamura, et al., Nature 1994, 369, 330-333). We have implemented an effective image processing algorithm for fast localization of gold labels on biological samples. We investigated spatial organization of Interleukin-2R alpha and -15R alpha (IL-2R alpha and IL-15R alpha) on a human CD4+leukaemia T-cell line, Kit225 FT7.10 by using transmission electron microscopy (TEM). TEM analysis showed co-clustering of the two types of alpha-chains even on the few-hundred-nanometer scale. The analysis of our data may contribute to our understanding the action of the IL-2/IL-15 receptor system in T-cell function.

[Assessment of in vitro immune response in a young population exposed to atmospheric contamination of Guadalajara]. / Evaluación de la respuesta inmunológica in vitro en una población joven expuesta a la contaminación atmosférica de Guadalajara.

BACKGROUND: Atmospheric pollutants may cause alterations on health of persons exposed to urban environment. OBJECTIVE: To evaluate in vitro immunological response in young population exposed to different levels of atmospheric pollution. PARTICIPANTS AND METHODS: The study was performed in two groups of young men, one from Guadalajara, and the other from Tlajomulco. The volunteers had to be healthy and without precedents of atopia. The immunological responses studied on PBMC were: stimulation index by timidin incorporation, CD25 expression by flow citometry, and production of citokines IL-2 and IL-4 by ELISAtest. Atmospheric parameters monitored were: NO2, O3, SO2, CO and PM10. RESULTS: In Guadalajara the concentrations of NO2 and PM10 exceeded in 30% and 40%, respectively, the index established by WHO. Stimulation index of PBMC of the young men to Guadalajara was 18 +/- 4, whereas that of the volunteers from Tlajomulco was 23 +/- 3. Expression of CD25 did not show a significant difference between studied groups. IL-2 and IL-4 levels were similar between the young men of the city and those from the rural area. CONCLUSION: The environmental pollution in Guadalajara did not modify in a significant way proliferation, CD25 expression, nor secretion of IL-2 and IL-4 on PBMC. This demonstrates that healthy young men are less susceptible than other groups to the alterations caused by exposure to moderate levels of atmospheric pollutants.

Suitable transmembrane domain significantly increase the surface-expression level of Fc(epsilon)RIalpha in 293T cells.

Evidence showed that the extracellular part of Fc(epsilon)RIalpha (FCR) with its own transmembrane domain (TMF) cannot be expressed as a transmembrane form in CHO cell line. However, FCR could be displayed on cell surface with the transmembrane domain (TM) of human IL2Ralpha (TMI). Theoretical analysis of TMF and TMI using TM prediction methods showed that TMI possessed strong orientation tendency to form "outside to inside" transmembrane mode from N-terminal to C-terminal, while TMF was prone to form "inside to outside" mode. Based on the analyzing results, the TM of Her2 (TMH) was studied and showed similar transmembrane mode as that of TMI, which implied that TMH might be a novel TM to obtain the surface display of FCR. Then, DNA sequences encoding TMH and TMF were fused to 3'-end of FCR gene, respectively. Fluorescent microscope observation indicated that FCR_TMH seemed to be located mainly on cell surface, while FCR_TMF appeared in endochylema. Flow cytometry analysis and Western blot also showed that the surface expression of FCR was enhanced significantly by TMH, while FCR_TMF could not be surface displayed in 293T cell. The experimental results were consistent with the theoretical predictions and demonstrated that the orientation tendency of TM may be very important in subcellular location of proteins.