Conversely, an increase in Bim could have interesting consequence

Conversely, an increase in Bim could have interesting consequences. Activation of Bim-mediated lymphocyte killing upon pro-apoptotic BH3-mimetics could adjust the balance between activated and regulatory lymphocyte populations and ameliorate colitis. Inducing apoptosis of autoreactive lymphocytes could be a new promising therapeutic

strategy for CD patients. This work was supported by the Swiss National Foundation (M.H., 31003A_127247) and the Broad Medical Research Program (M.H., IBD-0324R). We thank the microscopy centre at the University of Zurich (ZMB) for technical assistance. K.L., M.K., M.F. and M.H. have no conflicts buy LBH589 of interest to disclose. G.R. discloses grant support from Abbot, Ardeypharm, Essex, FALK, Flamentera, Novartis, Roche, Tillots, UCB and Zeller.

“The adenosine A2A receptor (A2AR) is the major cellular adenosine receptor commonly associated with immunosuppression. Here, we investigated whether A2AR activation holds the potential for impacting the severity of experimental autoimmune myasthenia gravis (EAMG) induced following immunization of Lewis rats with the acetylcholine receptor (AChR) R97–116 peptide. This INCB024360 cost report demonstrates reduced A2AR expression by both T cells and B cells residing in spleen and lymph nodes following EAMG induction. A2AR stimulation inhibited anti-AChR antibody production and proliferation of AChR-specific lymphocytes in vitro. Inhibition was blocked with the A2AR antagonists or protein kinase A inhibitor. We also determined that the development of EAMG was accompanied by a T-helper cell imbalance that could be restored following A2AR stimulation that resulted in increased Treg cell levels and a reduction in Th1-, Th2-, and Th17-cell subtypes. An EAMG-preventive treatment regimen was established that consisted of (2-(p-(2-carbonylethyl)phenylethylamino)-5-N-ethylcarboxamidoadenosine) (CGS21680; A2AR agonist) administration 1 day prior to EAMG induction. Administration

of CGS21680 next 29 days post EAMG induction (therapeutic treatment) also ameliorated disease severity. We conclude that A2AR agonists may represent a new class of compounds that can be developed for use in the treatment of myasthenia gravis or other T-cell- and B-cell-mediated autoimmune diseases. Myasthenia gravis (MG) is a B-cell-mediated, T-cell-dependent autoimmune disease characterized by excessive muscle weakness and fatigue [[1]]. The development of an autoimmune response to the neural acetylcholine receptor (nAChR) present at neuromuscular junctions leads to the production of function-blocking anti-nAChR antibodies and this results in symptoms characteristic to MG [[2, 3]].

The soluble anti-CD3 antibodies had no effect on T-cell prolifera

The soluble anti-CD3 antibodies had no effect on T-cell proliferation (data not shown). In addition, neither the scFv anti-CD33 by itself nor any of the fusion proteins carrying the costimulatory molecules was able to induce proliferation (Fig. 1). Suboptimal T-cell proliferation was observed at concentrations smaller than 5 μg/ml dscFv anti-CD33/anti-CD3. The combination of 10 μg/ml sc CD80/anti-CD33 fusion protein with

the suboptimal concentration of 2 μg/ml AZD1208 supplier dscFv anti-CD33/anti-CD3 did not significantly enhance T-cell proliferation above that seen with dscFv anti-CD33/anti-CD3 alone (Fig. 2a). In contrast, T-cell proliferation was significantly increased by the combination of 2 μg/ml dscFv anti-CD33/anti-CD3 and 10 μg/ml sc CD86/anti-CD33 (P < 0·05) and reached levels that were comparable with the higher doses of dscFv anti-CD33/anti-CD3 (10 μg/ml). Another functionally important T-cell activation parameter is their ability to kill target cells. In agreement with the proliferation data, concentrations of dscFv anti-CD33/anti-CD3 smaller than 5 μg/ml induced a suboptimal level of T-cell cytotoxicity when compared with 10 μg/ml dscFv Daporinad mouse anti-CD33/anti-CD3.

However, the level of cytotoxicity could be significantly enhanced by adding 10 μg/ml sc CD86/anti-CD33 to 2 μg/ml dscFv anti-CD33/anti-CD3 (Fig. 2b). Under these conditions cytotoxicity levels were almost identical to the levels achieved with 10 μg/ml dscFv anti-CD33/anti-CD3. Only a small and insignificant increase in T-cell cytotoxic activity could be observed when 10 μg/ml sc CD80/anti-CD33 fusion protein was added to 2 μg/ml dscFv anti-CD33/anti-CD3. This difference between CD86 and CD80 costimulation was not only restricted to the single dose of 10 μg/ml but was also seen over an entire dose range (0·01–10 μg/ml; data not shown). The magnitude of Ca2+ influx has been shown to correlate

with T-cell proliferation23,28 so we tested the hypothesis that differences in Ca2+ signalling are responsible for differences in T-cell activation observed during costimulation. To analyse Ca2+ signals in single cells following costimulation, we established conditions that allowed Loperamide us to measure Ca2+ signals in primary T cells following stimulation by bi-specific antibody-loaded CHO cells (Fig. 3a). Contact between T cells and CHO cells that were preloaded with dscFv anti-CD33/anti-CD3 (used at 2 μg/ml from now on) induced Ca2+ signals in almost all cells, whereas cells with no contact showed no Ca2+ signals. The ratio 340/380, which is proportional to [Ca2+]i, is shown over time for one T cell that makes a CHO-cell contact and one T cell that makes no CHO-cell contact (Fig. 3b). We observed [Ca2+]i rises only in cells with contact, but not in cells with no contact or in cases when only costimulatory antibodies were used (Fig. S3).

Our results showed that microvascular flaps afford successful com

Our results showed that microvascular flaps afford successful combined tissue reconstruction of the foot. © 2011 Wiley-Liss, Inc. Microsurgery, 2011. “
“Reconstruction of bony defects in the surgical management of vertebral osteomyelitis is a challenging endeavor. Our objective is to report the use of intra-abdominal vessels as the recipient vessels for microanastomosis of vascularized bone graft and the use of a spinal cage for fixation. Three patients failed conservative treatment for vertebral osteomyelitis and suffered pathologic fracture. Their treatment consisted of staged posterior irrigation and debridement with segmental fixation, followed by a thoracoabdominal approach multiple-level Selleck MLN0128 corpectomy. Reconstruction

was performed with a free vascularized fibular graft placed within a custom, expandable cage. The vascularized fibular graft was anastomosed to an intra-abdominal recipient vessel. All patients improved clinically with no neurologic deficits noted. All showed evidence of successful fusion. Free vascularized bone grafts ALK inhibitor continue to be an excellent option for multi-level spinal defects related to osteomyelitis. Intra-abdominal recipient vessels are appropriate recipient vessels, as their diameter, length, and accessibility allow vascularized bone graft reconstruction of vertebral column defects of the thoracolumbar region. These

vessels are also easily accessible and the anastomoses can be performed in the superficial operating incision. Fenbendazole © 2013 Wiley Periodicals, Inc. Microsurgery 33:560–566, 2013. “
“Background: Animal models and clinical cases of facial allotransplantation have been performed as a single stage procedure. A staged surgery might offer some advantages in selected cases. In this study, a two-stage face transplantation approach was performed on rat and the feasibility and safety were evaluated. Methods: Brown Norway rats were used as donors and Lewis rats as recipients in the allotransplantation

groups. A total of 33 hemiface-scalp transplantations were performed. Syngeneic orthotopic transplantations were performed either in one-stage (one single stage surgery; N = 3), local two-stage [heterothopic transplantation to the neck during the first stage and graft rotation as a pedicled flap to cover the facial defect on postoperative day (POD) 2; N = 3], or distant two-stage approaches (heterothopic transplantation to the groin during the first stage and free graft transfer to the face on postoperative day 2; N = 3). In the allotransplantation groups using the same approaches, 12 received no treatment (N = 4 each subgroup) and 12 received the same tapering dose of cyclosporine (10 to 2 mg/Kg/day; N = 4 each subgroup). Graft survival and the rejection grades were assessed clinically and pathologically. Results: All syngeneic transplants survived for the follow-up period of 180 days. The mean rejection-free survival and total survival of the allograft in the no treatment group was 6 ± 0.3 and 14.3 ± 4.

We are most grateful to the patients and controls who generously

We are most grateful to the patients and controls who generously donated blood samples and to Dr Misbah, Dr Lorton and Dr Patel, who care for these patients. We are also grateful to the staff at the Department of Clinical Laboratory Immunology at the Churchill Hospital, Oxford for their support and performing the lymphocyte subset analyses. Authors’ conflicts of interest: None declared. “
“Natural killer (NK) cell adoptive

transfer is a promising approach for cancer immunotherapy; however, its PF-562271 development has been hindered by the lack of efficient methods to produce large numbers of functional NK cells. In this study, we engineered the leukaemia cell line K562 to express FG-4592 concentration CD137 ligand (CD137L) and membrane-bound interleukin (mbIL)-21 on the cell surface, and used these cells to expand NK cells from the peripheral blood mononuclear cells. We found that purity of the NK cells (CD3−CD56+/CD16+) increased from less than 30% to above 95% after a 3-week expansion and proliferation of the cells was sustained for more than 8 weeks. The surface expression

of NK cell activating and inhibitory receptors, except for NKp80, was clearly increased with the expansion, and NK cell-mediated killing activity was also enhanced significantly. However, these changes in both phenotype and function were clearly reversed by JSI-124, a specific signal Forskolin transducer and activator of transcription-3 (STAT-3) inhibitor. Taken together, data showed that the combination of mbIL-21 and CD137L could efficiently induce the formation of functional human NK cells from peripheral blood mononuclear cells, and STAT-3 inhibition could impair this induction. Therefore, STAT-3 activation may benefit human NK cell proliferation and cytotoxicity, and provide valuable clinical applications in NK cell immunotherapy against viral infectious diseases and cancers.

Human natural killer (NK) cells are a subset of peripheral blood lymphocytes that are defined by their expression of CD56 and/or CD16 and the absence of T cell receptor CD3 [1]. NK cells can recognize and subsequently kill virus-infected and transformed cells in the absence of prior stimulation, and play a critical role in the immune surveillance of virus infectious diseases and cancers. NK cell killing is regulated through balanced signals from the activating and inhibitory receptors on NK cell surface [2]. A large number of studies have demonstrated that NK cells could elicit strong anti-tumour efficacy, and are promising effectors for adoptive immunotherapy against cancers [3]. NK cell alloreactivity could control leukaemia relapse without causing graft-versus-host disease (GVHD) [4]. Adoptive transfer of NK cells has been tested in early-phase clinical trials and has emerged as a safe and potentially efficacious immunotherapy for cancers [5].

pylori infection (Sayi et al , 2009) Conversely, IFN-γ can lower

pylori infection (Sayi et al., 2009). Conversely, IFN-γ can lower the colonization of H. pylori and is critical for H. pylori clearance (Yamamoto et al., 2004; Sayi et al., 2009). Most evidence indicates that IFN-γ plays a protective role in H. pylori infection (Sawai et al., 1999; Hasegawa et al., 2004; Yamamoto et al., 2004; Cinque et al., 2006; Sayi et al., 2009); furthermore, this occurs principally between IFN-γ and the bacteria. Our results provide further evidence that IFN-γ may help control H. pylori infection indirectly by controlling its virulence factor, CagA. Previous studies suggested that IFN-γ is a key

antimicrobial factor, against, in particular, intracellular pathogens such as viruses and Mycobacterium tuberculosis (Young et al., 2007). We too showed that Ceritinib in vivo IFN-γ can downregulate the expression of the major virulent factor CagA in the extracellular bacterium H. pylori for an indirect effect on such pathogens. IFN-γ

is a well-known immune active factor (Wu et al., 2005), and its production is accompanied by host immunity change in response to H. pylori (Shimizu et al., 2004; Pellicanòet al., 2007). In turn, IFN-γ can downregulate CagA expression. We found that H. pylori SS1 had the same effect as H. pylori 26695 (data not shown), but this needs to be confirmed by animal models. Hence, immune responses to H. pylori play an important role in the defense see more against bacterial infection. In conclusion, we found that INF-γ can bind to the surface of H. pylori, which results in the downregulated expression of CagA, the major virulent factor in H. pylori. These findings provide insights into understanding the effect of a high level of IFN-γ on gastric mucosa infected with H. pylori and how IFN-γ can CYTH4 contribute to control H. pylori infection. The mechanism by which IFN-γ causes downregulation of CagA needs further investigation. This work was supported by the National Natural Science

Foundation of China (Nos 30770118, 30972775, 30800406, 30800037, 30971151 and 30800614), the National Basic Research Program of China (973 Program 2007CB512001) and the Science Foundation of Shandong Province, China (Nos ZR2009CZ001 and ZR2009CM002). Yinghui Zhao and Yabin Zhou contributed equally to this work. Fig. S1. Effect of IFN-γ on the growth of Helicobacter pylori. Fig. S2. Binding of IFN-γ to Helicobacter pylori. Please note: Wiley-Blackwell is not responsible for the content or functionality of any supporting materials supplied by the authors. Any queries (other than missing material) should be directed to the corresponding author for the article. “
“The adenosine monophosphate-activated protein kinase (AMPK) is activated by antigen receptor signals and energy stress in T cells. In many cell types, AMPK can maintain energy homeostasis and can enforce quiescence to limit energy demands.

Furthermore, a laboratory-adapted clone of Caulobacter crescentus

Furthermore, a laboratory-adapted clone of Caulobacter crescentus

exhibited a ~ 20% greater growth rate than its progenitor strain and this entire phenotype was explained Adriamycin purchase by a single SNP altering the expression of glucose-6-phosphate dehydrogenase (zwf) (Marks et al., 2010). This enzyme controls the primary flux between energy generating glycolysis and the precursor generating pentose-phosphate pathway (PPP). It was shown that lower flux through PPP with concomitant increased glycolytic activity lead to higher growth rates in laboratory-adapted C. crescentus (Marks et al., 2010). Interestingly, one of the very genes exhibiting signs of positive selection in USA300 was zwf along with two glycolytic genes (pgm and pfkA) potentially linked to the USA300 growth advantage on numerous carbon sources (Holt et al., 2011). Whether or not SNPs within these metabolic genes account for enhanced USA300 growth rates and whether that contributes to the success of this clone remain to be proven; however, the unusual SNP distribution among metabolic genes in USA300 combined with its enhanced growth

rate suggest there may be more to USA300 virulence than newly acquired or overexpression of virulence genes. The overwhelming success of USA300 in North America as the dominant source of CA-MRSA infections represents a fascinating example of a pathogenic variant emerging as a new threat to human health. The adaptations acquired by USA300 clones in the form of novel genetic components, altered gene regulation, and sequence polymorphisms likely act in concert to provide these strains with a selective buy MK-2206 advantage. It appears as though USA300 hypervirulence, as assayed in animal models of infection, correlates with increases in virulence gene expression and is apparent in HA-MRSA progenitors as well as other

unrelated CA-MRSA lineages. Rucaparib molecular weight Whether this is because of hyperactive Agr resulting in elevated PSM production and Sae expression (which in turn could lead to excess Hla and other exoprotein excretion) remains to be proven. In contrast to overt virulence, traits that affect transmission and colonization efficiency are inherently difficult to model in the laboratory. It may prove, however, that this aspect of USA300 biology is as critical to its success as is high virulence potential. It remains to be determined whether newly acquired genetic components (e.g. ACME) and/or sequence polymorphisms contribute to the rapid transmission and success of USA300 in the community. In the end, we may appreciate that none of the three evolutionary events (gene acquisitions, altered gene regulation, protein sequence divergence) outlined here can alone explain the success of USA 300. Rather, the amalgamation of all these events created the highly successful pathogen that we must contend with today. This work was supported by funding from the NIH (AI088158 to A.R.R.

BGI coverage was at an average read depth of 30 and AUSCam covera

BGI coverage was at an average read depth of 30 and AUSCam coverage was at an average read depth of 200. Mutations were detected in LMX1B, KCNJ5, NPHP1, NPHP3, ATP6VA04, CFH and CFHR5 resulting in confirmed genetic diagnosis in 3 of 5 patients with bioinformatics completed to date. Conclusions: The promise of massively parallel sequencing click here to secure genetic diagnosis can be realised for patients with genetic renal diseases in Australian clinical practice.

Continued evolution and refinement of the local disease-targeted approach (AUSCam) continues and may result in a valuable tool for genetic diagnosis with implications for future treatment and management options. 193 CLINICAL CHARACTERISTICS AND SUPPORTIVE CARE REQUIREMENTS OF PATIENTS WITH ATYPICAL HAEMOLYTIC URAEMIC SYNDROME:

A RETROSPECTIVE, SINGLE CENTRE REVIEW N ISBEL1,2, D LEARY1, S PAYNE3 1Department of Nephrology, Princess Alexandra Hospital, Brisbane, Qld; 2The University of Queensland at the Princess Alexandra Hospital, Brisbane, Qld; 3Alexion Pharmaceuticals, Australia Aim: To improve understanding supportive care requirements in aHUS patients. Background: aHUS is an ultra-rare, genetic, life threatening and complement-mediated condition associated with premature mortality and high rates of end organ damage. Patients check details were managed with plasma exchange/infusion (PE/PI), transfusions and dialysis. Despite this, 33–40% of patients die or reach end-stage kidney disease (ESKD) after their first manifestation of disease. Methods: Retrospective, de-identified data was collected for all aHUS patients consented to the global aHUS Registry and treated at Princess Alexandra Hospital (PAH) Brisbane, Australia with their first presentation of TMA between

2008 and 2012. Results: All (5) patients were female and Caucasian with a median selleck screening library age of 37 years. All patients had a clinical diagnosis of aHUS and received PE/PI for management of TMA. A mean of 234 (range 45–570) units of fresh frozen plasma (FFP) were given, 1 patient receiving 938 units of cryodepleted plasma. The median cost of FFP alone was $73,337 (range $14,103–$178,643). 60% (3/5) of patients experienced adverse events related to PE/PI. Patients were also managed with red blood cell, platelet and intravenous immunoglobulin transfusions. Eculizumab was not administered to any patient during this period. Patients were hospitalised for a median of 52 (range 4–284) days and attended a median of 64 (range 31–350) clinic appointments. All patients developed renal impairment following their first presentation, 60% of patients reached ESKD/dialysis. 80% (4/5) of patients experienced extra-renal complications of aHUS, 3 of whom experienced >1 extra-renal complication. Conclusions: Management of aHUS patients with currently available supportive care necessitates extensive utilisation of healthcare resources.

Again in a population with gastrointestinal leakages but addition

Again in a population with gastrointestinal leakages but additionally including patients with acute necrotising pancreatitis, the same group recently showed in a pilot non-comparative trial that caspofungin was successful in the prevention of intra-abdominal check details IC in 18/19 patients (95%, one breakthrough IC 5 days after inclusion).80 This finding will have to await confirmation in a randomised trial. Moreover, it may not be the most prudent choice to use echinocandins for prophylaxis as these agents have evolved as an important option for therapy of established Candida infections. In a double-blind

placebo-controlled trial, Garbino et al. [81] investigated low-dose fluconazole (100 mg Temozolomide day−1) in mechanically ventilated ICU patients and found a significant reduction of the rate of candidaemia episodes but with no mortality benefit. Pelz et al. [82] used a predicted ICU stay of >3 days on admission as an inclusion criterion in their placebo-controlled trial using 400 mg day−1 fluconazole for prophylaxis. In a time-to-event analysis, the risk of IC in the fluconazole arm was significantly reduced vs. placebo. However, the proven infection rate in

the placebo arm was 61% after 21 days, which is a quite unusual finding precluding general conclusions from the results. Even at this unacceptably high background fungal infection rate, no survival benefit was observed in the prophylaxis arm. Nonetheless, in their current guidelines the IDSA recommends the prophylactic

use of fluconazole in for high-risk patients in adult ICUs with a high incidence of IC (>10%). mafosfamide However, apart from the patients with intra-abdominal leakage, it remains largely unclear as to which specific risk factor profiles are associated with a benefit from antifungal prophylaxis. Objections to the prophylactic use of antifungal drugs in ICU patients include the potential to select for species or strains with reduced azole susceptibility. However, in none of the prophylaxis trials in the ICU setting this kind of pathogen shift was observed.42 While invasive Candida species clearly are the leading cause of invasive fungal infections in the ICU, invasive aspergillosis (IA) has been described in ICU patients at varying incidence rates. In a retrospective autopsy-controlled study, as many as 6.9% of patients had histopathological or microbiological evidence of IA, 70% of these patients did not suffer from underlying haematological malignancies, one of the classical risk factors for IA.83 The mortality was 80%, much higher than predicted from Simplified Acute Physiology Score values. Other studies suggest that IA is among the frequently undiagnosed conditions in ICU patients.84 While in most ICU the incidence rate may be much lower than that described above, awareness of Aspergillus spp.

β-Lactamase-mediated ampicillin resistance rates for the 125 isol

β-Lactamase-mediated ampicillin resistance rates for the 125 isolates were 16.4% for the respiratory isolates and 20% for the invasive isolates. These rates agree with previous reports of a decline in the prevalence of β-lactamase-producing NT Hi in recent years in both Canada and the United States (Zhanel et al., 2003; Heilmann et al., 2005). There was no statistical significance between the invasive and respiratory groups of NT Hi see more in the prevalence

of β-lactamase-mediated ampicillin resistance (P≥0.05 by χ2). However, significantly more invasive isolates (15% or 26.8%) than respiratory isolates (5% or 10.9%) were found to show decreased susceptibility towards ampicillin (P≤0.05 by χ2), possibly indicating a chromosomal-mediated ampicillin resistance mechanism that AZD3965 involves amino acid substitutions in the penicillin-binding protein 3 (PBP3) (Ubukata et al., 2001). Indeed, we have recently reported that Canadian β-lactamase-negative Hi showing decreased susceptibility towards ampicillin have significant mutations in their PBP3 (Shuel & Tsang, 2009). Further analysis in the future should monitor for this stepwise increase in their resistance to ampicillin. Of the 70 invasive Hi disease cases due to NT strains, 20 (or 28.6%) were in those 61–80 years of age and another 10 (14.3%) were in those 41–60 years of age. COPD is a common

morbidity, especially in the elderly (Murray & Lopez, 1997), and in the United States, 500 000 hospitalizations annually have been related to infections or acute exacerbations in patients with COPD (Snow et al., 2001). Because Hi, particularly the

NT strains, are common causes of acute exacerbations of chronic bronchitis in COPD patients (Sethi & Murphy, 2001), whether the high prevalence of NT Hi causing invasive diseases in those aged 41–80 in this study may be related to infections in COPD patients is worth examining in more detail. However, our present retrospective study did not allow us to look into this further without first obtaining ethics approval for reviewing patients’ medical history and coordination with Florfenicol individual hospital’s medical staff. Besides COPD, elderly patients (in the 61–80-year-old age group) are more likely to have other medical conditions such as diabetes, decreased immune functions, etc., which may predispose them to invasive infections by common respiratory bacteria such as NT Hi. One limitation of our study is the retrospective nature, which resulted in the lack of clinical correlations with the types of strains identified among the invasive and the respiratory isolates. Because of this lack of clinical data, it is not possible to identify whether any of the genotypes among the invasive isolates are genuinely virulent in causing disease in immunocompetent individuals.

7B) In addition, the proliferation of LPL knock-down T cells was

7B). In addition, the proliferation of LPL knock-down T cells was attenuated (Fig. 7C). Since the shorter calcium signal of knock-down DAPT nmr T cells is the consequence of a reduced contact time with APC (Fig. 7A and B), it was tempting to speculate that antibody stimulation of T cells neutralizes this effect as this kind of stimulation is independent on T-cell/APC contact time. This was indeed the case (Supporting Information Fig. 8). In marked contrast to stimulation via APC, stimulation via antibodies induced an equal calcium influx in both control and LPL knock-down T cells. Furthermore, there was no inhibition

of proliferation if LPL knock-down T cells were stimulated via crosslinked antibodies (Supporting Information Fig. 8). Thus, the attenuated proliferation of LPL knock-down T cells upon stimulation with APC may at least rely in part on the reduced contact time and the short calcium signals. The activation of antigen-specific T cells is initiated by interaction of T cells with APC bearing the cognate antigen. Thereby, an ordered contact zone, called IS,

is established. The actin cytoskeleton is indispensable for spatial arrangements of a multitude of receptors and proteins that finally define a mature IS at the T-cell/APC contact zone 9, 30. Intracellular proteins regulating the selective spatio-temporal receptor accumulation to the IS were, however, so far not known. Employing RNAi-guided experiments here, we demonstrate that the actin-bundling EGFR inhibitor protein LPL is crucial for the stabilization of LFA-1 in the IS, the duration of T-cell/APC contact formation and sustained calcium signaling. Thus, LPL is an important regulator for the temporal organization of IS formation and T-cell

activation. There are a couple of evidences that the initial relocalization of LPL in the IS is dependent on actin polymerization. Thus, LPL completely colocalized with F-actin in the IS and deletion of the actin-binding domains of LPL interfered with its relocalization. Moreover, it was described that T-plastin binds only to newly formed actin enough filaments, a process which can be considered as actin–plastin copolymerization 14, 15. Therefore, it is likely that the actin/LPL copolymerization in the IS is the major force that brings LPL in the IS. Vice versa, LPL seemed to stabilize F-actin since LPL knock-down T cells had a reduced amount of total F-actin. Given that LPL might protect F-actin from being depolymerized by cofilin 16, F-actin depolymerization may be enhanced in LPL knock-down cells, whereas actin polymerization may be comparable with control cells. In this scenario, F-actin fibers were smaller, which could contribute to the reduced synapse size. Our data show that actin polymerization and accumulation in the T-cell/APC contact zone are required but not sufficient to establish a mature IS.