Four of the nine mutations (9%) that were detected in embB306 indicating resistance to ethambutol were not detected by the DST method, giving the lowest rate of concordance (44.4%) of the PCR with the DST method. One of the greatest concerns of national tuberculosis control programs in several countries

is the emergence and spread of drug resistant and MDR-TB. The actual extent and type of drug-resistant tuberculosis in Jordan is unknown. To determine this, the present study characterized 100 M. tuberculosis strains by PCR that were identified as drug resistant in the reference laboratory for mycobacteria. This is the first investigation involving the molecular characterization of drug resistance of M.

tuberculosis clinical isolates from Jordan. It was initiated as a result of the growing demand for rapid molecular characterization selleck screening library of Mycobacterium Copanlisib strains isolated from patients whose clinical details and history suggested the presence of drug-resistant M. tuberculosis, i.e. previous tuberculosis, recent immigration from or travel to an area with a high prevalence of MDR-TB, failure to respond to therapy, or contact with a known MDR-TB patient (Watterson et al., 1998). In this study, 34 isolates resistant to one or more of the tested drugs were identified. This is comparable to what has been reported in the neighboring countries, with resistance to isoniazid and rifampicin being more common than resistance to ethambutol. The World Health Organization has estimated the prevalence of MDR-TB in several Mediterranean and neighboring only countries as follows: Bahrain 3.5%, Egypt 5%, Iran 7.1%, Iraq 5.6%, Israel 5.6%, Kuwait 2.4%, Lebanon 2.4%, Oman 1.8%, Qatar 1.1%, Saudi Arabia 3.4%, United Arab Emirates 3.8%, and Yemen 3.2% (WHO, 1997, 2000a, b, 2003). In Jordan, there is very limited documentation of MDR-TB cases. Previous studies reported that over 90% of the M. tuberculosis rifampicin-resistant

clinical isolates harbored mutations in the 81-bp core region of the rpoB516, rpoB526, and rpoB531, the most frequent (70–95%) worldwide (Bártfai et al., 2001; Mokrousov et al., 2003). The discrepancies between the molecular and phenotypic drug resistance reported in this study have been reported by others previously (Baldeviano-Vidalon et al., 2005; Chan et al., 2007; Plinke et al., 2009). These discrepancies are most likely caused by problems with conventional susceptibility testing (Plinke et al., 2009) or by a single base substitution of a silent point mutation. Another possibility is the presence of heterogeneous isolates or mixed populations of resistant and susceptible M. tuberculosis bacilli in the initial sputum specimens with mutant genotypes being recognized by the molecular assay and therefore masking or dominating the susceptible genotypes.

The ability to determine the affinities and off-rates of peptides binding to MHC class I molecules will help to elucidate the time frame for which an individual epitope is available CP868596 for T-cell priming. Previous studies have shown a correlation between high-affinity peptides and immunogenicity,31 while other studies failed to identify such a link.32 HLA-A alleles showed a wide range of both peptide affinity and off-rate; generally the peptide affinity was lower and the off-rate faster for the HLA-B alleles reported here. This is consistent with a previous study, in which the affinity of peptide epitopes generally tended to be lower for HLA-B alleles than for HLA-A alleles.33 We also observed that the

‘promiscuous peptides’ bound with different affinities and off-rates to MHC class I molecules; this behaviour may determine which MHC class I–peptide complexes are ‘immunodominant’ or ‘subdominant’ in CD8+

T-cell responses. Using tetramer technology, we confirmed the presence of TB10.4 epitope-specific Alectinib clinical trial CD8+ T cells for most of the candidate peptides in patients with TB. The fact that some of the identified epitopes do not seem to be recognized by any CD8+ T cells may have several explanations. One explanation could be that certain peptides may not be generated in vivo because of proteasomal processing, or because of differential affinity for the transporter protein (TAP) and trimming by aminopeptidases.34 Other reasons may be that no TCRs are able to bind to the MHC class I–peptide complex, or antigen-specific T cells may not have been expanded by APC contact.35 In addition, we analysed PBMCs from patients with active pulmonary TB. It could very well be that local pulmonary immune Cobimetinib cell line responses36 show a different profile or that the focus of the CD8+ T-cell response changes over time after reduction of bacterial load as a result of anti-TB treatment.37 The fact that most TB10.4 antigen-specific T cells were identified using HLA-B tetramers supports the notion that the CD8+ T-cell response to Mtb antigens appears to be mainly HLA-B restricted. This is consistent with previous studies on TB,19,38

but also with those on viral diseases, i.e. infcetions with HIV,39 Epstein–Barr virus (EBV32) and cytomegalovirus (CMV40). The cause of this ‘immunodominance’ is not that HLA-B alleles have a broader peptide-binding repertoire than HLA-A alleles;33 in fact, our current study confirms that HLA-A alleles exhibit a more diverse peptide-binding repertoire. HLA-B immunodominance may be linked to either differences at the MHC expression level on APCs and/or differences in the TCR repertoire that is available to recognize the respective MHC class I–peptide complex. One may speculate that the lower affinity and shorter off-rate between the candidate peptides and HLA-B alleles may prevent the ‘immune exhaustion’ that may occur in MHC class I high-affinity binding epitopes in chronic infections, including TB.

For cytofluorimetric analysis (FACSCalibur, Becton Dickinson

& Co, Mountain View, CA, USA), cells were stained with the appropriate unlabeled mAbs followed Erastin by PE-conjugated isotype-specific goat anti-mouse secondary Ab (Invitrogen-Life Technologies, Carlsbad, CA, USA; Southern Biotechnology Associated, Birmingham, AL). For the evaluation of apoptotic/dead cells, the AV/PI staining kit (Bender Systems, Wien, Austria) was used following the manufacturer instructions. The gating strategies to assess AV/PI staining or to evaluate NK-receptor expression are shown in Supporting Information Fig. 3. For CD107 mobilization, 2 × 105 NK cells cultured in IL-2 either under hypoxic or normoxic conditions were cocultured with 2 × 105 target cells (FO-1 or P815 cells) in 96 V-bottom well

plates. PE-conjugated Panobinostat in vivo anti-CD107a mAb was added in each well at the onset of the coculture. NK cells and target cells were coincubated for 4 h at 37°C in 5% CO2; after the first hour of coincubation, Golgi Stop (Becton Dickinson) was added. Cells were then washed in PBS with 2 mM EDTA and stained with the appropriate fluorochrome-conjugated mAbs. Analysis of CD107a surface expression in NK cells mixed with FO-1 cell line was done on cells double-stained with FITC-conjugated anti-CD45 and allophycocyanin-conjugated anti-CD56 mAbs. To detect spontaneous degranulation, a control sample without target cells was included. NK-cell incubation with the FcγR+ P815 murine cell line was done either in the absence or in the presence of IgG1 mAbs BCKDHA specific for the receptors indicated in the text. Analysis of CD107a surface expression in NK cells mixed with P815 cell line was

done on cells stained with APC-conjugated anti-CD56 mAb. NK-cell populations were tested for cytolytic activity in a 4-h 51Cr-release assay against either two human melanoma cell lines (i.e. FO-1 and MeCoP), the B-EBV cell line 721.221 (i.e. 221), or the FcγR+ P815 murine cell line. The concentration of the various mAbs added in the redirected killing and in the ADCC experiments was 1 μg/mL. The E:T ratios are indicated in the figures. Statistical analyses were performed using the Prism software package (release 5.00; GraphPad Software). Statistical significance was evaluated by two-tailed paired Student’s t-test. A p value of less than 0.05 (*), less than 0.01 (**), or less than 0.001 (***) was considered statistically significant. This work was supported by grants awarded by Associazione Italiana per la Ricerca sul Cancro (A.I.R.C.): IG project numbers 5282 (M.V.), 10565 (L.V.), 10225 (L.M.), MFAG project number 6384 (G.P.), and “Special Program Molecular Clinical Oncology 5×1000” project number 9962 (L.M.); Ministero dell’Istruzione, Università e Ricerca (MIUR): MIUR-FIRB 2003 project RBLA039LSF-001 (L.M.

Progression of bacterial growth to the bloodstream was monitored by blood samples obtained by cardiac puncture with a heparinized syringe. Samples were plated on blood agar and bacteraemia RG-7388 mw was reported as negative or positive haemocultures after incubation for 18 h at 37°C. Experiments were performed in triplicate and results were expressed as mean ± standard deviation (s.d.). Significant differences between means were determined by analysis of variance

(anova) with Fisher’s least significant difference (LSD) post hoc test using the StatGraphics software (Manugistics, Rockville, MD, USA). Differences were considered significant at P < 0·05. We evaluated administration of the probiotic strain L. casei by oral (O) and nasal (N) routes associated with nasal immunization with live (LL) and inactivated

(D-LL) recombinant strains. Results are shown in Fig. 1a and b and significant differences between groups on day 42 are shown in Table 1. The D-LL + Lc (N) (IgA: P < 0·001, IgG: P < 0·01), D-LL + Lc (O) (IgA: P < 0·01, IgG, P < 0·001) and LL + Lc (O) (IgA: P < 0·05, IgG: P < 0·001) groups showed the highest levels of IgA and IgG anti-PppA in bronchoalveolar lavages GSK1120212 price in comparison with the live vaccine. D-LL + Lc (N) induced the highest IgA levels in BAL, but without significant differences with the D-LL + Lc (O) and LL + Lc (O) groups. Although D-LL induced significantly high values of specific IgA (P < 0·05) and IgG (P < 0·05) antibodies compared to live vaccine (LL), IgA values

were lower than those obtained in the groups receiving the probiotic. The levels of specific anti-PppA IgM were increased slightly compared Carnitine palmitoyltransferase II to those of LL in the groups that received Lc as an oral or nasal adjuvant associated with the inactivated vaccine, especially on day 28, although the differences were not significant (data not shown). Results showed that administration of the probiotic strain by both the oral and nasal routes exerted an important adjuvant effect on the humoral immune response in the lung compartment. This would provide an encouraging alternative for the use of vaccines involving the probiotic–inactivated recombinant bacterium association, with their associated advantages: adjuvant properties of the probiotic strain and safe application of an inactivated bacterium to human health. As expected, the groups that received only PBS, Lc (O) or Lc (N) showed no levels of specific anti-PppA antibodies. Nasal immunization with LL induced a good response of specific IgA, IgG and IgM antibodies in serum (Fig. 2a–c). The associated administration of the probiotic by the oral route did not induce a significant increase in the levels of these specific immunoglobulins in any of the assessed groups (Fig. 2).

This finding indicates the need check details for periodical autoantibody analysis and inspection for the appearance of symptoms suggesting autoimmune disease. However, treatment of these patients remains the same. Relevant to this, it was demonstrated that treatment with danazol in HAE patients significantly increases C4, haemolytic complement 50% levels and the disappearance of circulating immune complexes [33]. Therefore, it could be speculated that the promotion of C4 synthesis by danazol could possibly result in the decrease of B cell activation and autoantibody generation. However, we did

not find any difference between treated and non-treated patients with regard to B cell activation and autoantibody generation. Nevertheless, Selleck Epacadostat further studies are needed to clarify this point. In summary, we suggest that HAE patients have enhanced production of autoantibodies compared to the general healthy population, due most probably

to activation of B cells which associate with high expression of TLR-9. B cells might be activated by immune complex and thereby have the potential, in certain genetic backgrounds, to break tolerance and trigger autoimmunity. None. “
“B7-H3 is a B7-family co-stimulatory molecule and is broadly expressed on various tissues and immune cells. Transduction of B7-H3 into some tumours enhances anti-tumour responses. We have recently found that a triggering receptor expressed on myeloid cell-like transcript 2 (TLT-2) is a receptor for B7-H3. Here, we examined the roles of tumour-associated B7-H3 and the involvement of TLT-2 in anti-tumour immunity. Ovalbumin (OVA)257–264-specific OT-I CD8+ T cells exhibited higher cytotoxicity against B7-H3-transduced OVA-expressing tumour cells (B7-H3/E.G7) in vitro and selectively eliminated B7-H3/E.G7 cells in vivo. The presence of B7-H3 on target cells efficiently augmented CD8+ T-cell-mediated cytotoxicity against alloantigen or OVA, whereas

the presence of B7-H3 in the priming phase did not affect the induced cytotoxicity. B7-H3 transduction about into five tumour cell lines efficiently reduced their tumorigenicity and regressed growth. Treatment with either anti-B7-H3 or anti-TLT-2 monoclonal antibody accelerated growth of a tumour that expressed endogenous B7-H3, suggesting a co-stimulatory role of the B7-H3–TLT-2 pathway. The TLT-2 was preferentially expressed on CD8+ T cells in regional lymph nodes, but was down-regulated in tumour-infiltrating CD8+ T cells. Transduction of TLT-2 into OT-I CD8+ T cells enhanced antigen-specific cytotoxicity against both parental and B7-H3-transduced tumour cells. Our results suggest that tumour-associated B7-H3 directly augments CD8+ T-cell effector function, possibly by ligation of TLT-2 on tumour-infiltrating CD8+ T cells at the local tumour site.

Intracranial localization is very rare and only a few cases have been reported. This report intends to present the clinical, radiological and pathological pictures of a primary central nervous system angiosarcoma along with a review of the literature. A 35-year-old woman presented at our institution with weakness and sensory disturbances of her

right hand. Neuroimaging revealed a roughly round, hemorrhagic and moderately enhancing lesion in the left frontal posterior region. The tumor was totally removed under awake anesthesia and continuous monitoring of motor and language functions. Histopathology revealed JQ1 price an epithelioid angiosarcoma. Radical removal, followed by adjuvant radiotherapy and chemotherapy, is able to completely control the disease for a relatively long period. “
“We studied one frontal lobe tumor and multiple spinal cord tumors (one in an extramedullary location) that had been resected from a 24-year-old man. The frontal lobe tumor was well demarcated and non-infiltrating, and consisted of eosinophilic, elongated fibrillary cells arranged in a fascicular pattern. A similar histology was reproduced

in the spinal cord tumors, with additional areas showing standard features of ependymoma. Immunohistochemical and ultrastructural observations revealed that all the tumors were ependymal in nature with positivity for GFAP and epithelial membrane antigen and negativity for oligodendrocyte transcription factor 2, showing intra- and intercellular microrosettes, leading us to a diagnosis of tanycytic ependymoma for the frontal lobe tumor and tanycytic ependymoma BIBW2992 purchase with ordinary ependymomatous component for the spinal cord tumors. The spinal extramedullary tumor was a schwannoma. Importantly, http://www.selleck.co.jp/products/Gefitinib.html a heterozygous truncating mutation in the NF2 gene was identified in the blood lymphocytes from the patient. It is known that multiple nervous system tumors can occur in neurofibromatosis type 2 (NF2), which is caused by mutation in the NF2 gene, and that

occurrence of ependymoma, including the tanycytic variant, can be associated with this genetic condition. The present case provides further information about the clinicopathology of tanycytic ependymoma with details of the immunohistochemical, ultrastructural and genetic features. “
“Chordoid glioma is a rare, slowly growing tumor of the CNS, which is always located in the third ventricle of adults. Chordoid glioma has classic histological features consisting of clusters and cords of epithelioid tumor cells embedded within a mucinous stroma with rich lymphoplasmacytic infiltrate. The important distinctive immunohistochemical feature of this neoplasm is strong and diffuse reactivity for GFAP. Here, we report four cases of chordoid glioma that occupied the anterior portion of the third ventricle or suprasellar region. These four cases were all adult females with almost typical clinical, radiological, histologic and immunohistochemical characteristics of chordoid glioma.

3d,e).

We also observed that the extent of the reduction of naive T cells from Stat3-deficient mice was larger than that of memory/effector T cells when compared with the control group (Fig. 3d,e). It is accepted that the homeostasis of naive T cells is maintained by the combination of self-peptide MHC complexes and IL-7 signals.[4, 5] Also, IL-2 plays crucial roles in the differentiation of naive T cells into memory T lymphocytes.[26] Moreover, both IL-2 and IL-7 activate Stat3 in T cells.[19] Hence, we suggest that Stat3 supports the maintenance and expansion of the naive T-cell pool through the IL-7 receptor signals, as well as mediating memory/effector T-cell production via IL-2-induced signal transduction. Consistently,

we showed that both the naive and memory/effector T cells in peripheral lymphoid Deforolimus mouse organs were significantly deficient in Stat3 knockout mice. Because the mice contain a Cre transgene driven by the distal promoter of Lck gene, Cre-recombinase expression is mainly observed in T cells after T-cell receptor α (Tcra) locus rearrangement and after the process of positive FK228 manufacturer selection in thymic cortex.[27] To identify whether the T-cell deficiency in Stat3 knockout mice was attributable to the dysregulation of thymic development, we would have to observe the CD4 and/or CD8 expression pattern in thymocytes from wild-type or Stat3 knockout mice (Fig. 4a). CD4 or CD8 SP cells were unvarying in both groups of mice at 4–8 weeks old (data not shown). However, we observed considerable decreases of both CD4 and CD8 SP cells in thymocytes from Stat3-deficient mice at 6 months old

(Fig. 4a,b). A possible mechanism for this finding is that the failure to compensate the Stat3 Adenosine deficiency occurred on the maintenance of the CD4 or CD8 SP population in aged mice, while it works intact at younger age. Stat5, as a candidate molecule for compensating Stat3 deficiency in thymocytes, has been reported to play a crucial role in the thymic development including maintenance of CD4 or CD8 SP thymocytes.[28] Together with the Stat3, Stat5 is a key signal transducer for the IL-2 and IL-7 receptor signalling in T cells.[29] Furthermore, the activity of Stat5 is much reduced in ageing thymus.[29, 30] We therefore speculate that the pro-survival signals delivered from IL-2 or IL-7 receptors successfully lead to the expression of downstream targets such as Bcl-2 and Bcl-xL through Stat5 activation, which is sufficient in young mice even when Stat3 is deficient. However, the expression of Bcl-2 or Bcl-xL might be unable to be maintained in Stat3-deficient mice at an old age because the activity of Stat5 is dramatically decreased in ageing thymocytes. We also demonstrated that the susceptibility to apoptosis was enhanced and the expression of Bcl-2 and Bcl-xL was significantly reduced in thymocytes from Stat3 knockout mice (Fig. 4c,d).

If true, the regulatory

mechanisms explaining these virulence trait expression phenomena are poorly defined. Staphylococcus aureus expresses a peptide-based quorum sensing system known as Agr for Accessory Gene Regulator (Bohach, 2006; Thoendel et al., 2011). Signaling is mediated through a peptide form of AgrD [processed by the combined activity of the AgrB endopeptidase and a type I signal peptidase, SpsB (Kavanaugh et al., 2007)] that stimulates the two-component system sensor kinase, AgrC. The resulting activation of the response regulator AgrA leads to induction of the agrBDCA operon as well as the divergently transcribed RNAIII. While RNAIII encodes δ-toxin, the RNA molecule itself mediates a significant proportion of Agr regulation by affecting the selleck inhibitor expression of α-toxin (Novick et al., 1993), protein A (Vandenesch et al., 1991), repressor of toxins (Rot) (Geisinger et al., 2006), and others (Vanderpool Ensartinib et al., 2011). Active AgrA is also known to directly control the expression of other virulence determinants including the PSMs (Queck et al., 2008). Thus, the reported overproduction of Hla, Hld, and PSMs in USA300 clones may be explained by a hyperactive Agr system in these clones. Indeed, the RNAIII molecule was shown to be expressed to a higher level in USA300 clones than in other S. aureus isolates explaining the overabundance of δ-hemolysin

production (Montgomery et al., 2008; Li et al., 2010). Additionally, the overactive USA300 Agr system was Amobarbital the source of excess PSM and protease production associated with these clones and was partially responsible for excessive Hla expression (Cheung et al., 2011). Consistent with these data, ∆agr mutants in USA300 are highly attenuated in murine sepsis, pneumonia, and skin abscess models (Montgomery et al., 2010; Cheung et al., 2011; Kobayashi et al., 2011). Though, given the importance of Agr in virulence gene regulation, it is not surprising that mutants exhibit such attenuation. Moreover, overproduction of PSMs was reported for USA400 CA-MRSA clones implying that the greater success of USA300 cannot be fully attributed to overactive Agr (Wang et al.,

2007; Li et al., 2010). In fact, USA500 clones, thought to be ancestral to USA300, also exhibit phenotypes with hyperactive Agr as well as being highly virulent in murine model infections (Li et al., 2009, 2010). Thus, the high virulence potential of USA300, including high Agr activity, likely evolved in the HA-MRSA clones belonging to USA500. Still, ∆agr mutants of USA300 are highly attenuated and exhibit no increased virulence relative to non-USA300 agr mutants underscoring its importance in the evolution of USA300 (Cheung et al., 2011). The S. aureus exoprotein expression (Sae) locus contains four genes, saePQRS the latter of which comprise a two-component regulatory system (Giraudo et al., 1994, 1999; Adhikari & Novick, 2008).

Upon aGVHD development in the group of mice receiving PBMC alone (positive control)

(days 12–15), target organs and sera were harvested from all groups for histological analysis, serum analysis and cell characterization. All experiments were repeated two or more times with five to seven mice per group on each occasion. Target organs (lung, liver and gut) were recovered from mice (days 12 or 15) and fixed in 10% (v/v) buffered formalin, processed for histology and embedded in paraffin wax. Five-μm tissue sections were stained by haematoxylin and eosin (H&E) and coded without reference to prior treatment, blinded and then examined by two independent observers. A semi-quantitative scoring system was used to assess abnormalities in the lung, liver and gastrointestinal tract (GI) tract [30-32]. Human bone marrow mesenchymal stem cells were generated as previously described [33] in collaboration with the Regenerative HM781-36B research buy Medicine Institute (REMEDI, NUI Galway, Ireland). Briefly, bone marrow

aspirates were taken from the iliac crest of healthy consenting adult donor patients according to an approved clinical protocol [34]. Human MSC batches used in this study conformed to the International Society for Cellular Therapy (ISCT) criteria [16] and were capable of differentiation to adipocytes, osteocytes and chondrocytes and were only used at low passage (3–8). Human MSC were cultured in complete Dulbecco’s modified Eagle’s medium (DMEM) (Invitrogen-Gibco, Dublin, Ireland) supplemented with 10 % (v/v) fetal bovine serum (FBS), 200 U/ml penicillin and 200 μg/ml streptomycin. In some instances, Cisplatin MSC were stimulated with recombinant human IFN-γ (500 U/ml) (Peprotech, London, UK) for 48 h and washed extensively with PBS prior to their use in vitro or in vivo. For in-vitro apoptosis, PBMC (0·5 × 106/ml) were co-cultured with MSC (1·5 × 105/ml) in complete RPMI (cRPMI) in the presence or absence of 500 μg/ml cisplatin (control) (Sigma-Aldrich, Arklow, Ireland). After 24 h, PBMC were recovered by gentle aspiration

from adherent MSC and apoptosis was detected by annexin V/propidium iodide (PI) staining (BD Biosciences, Oxford, much UK), measured by flow cytometry using a BD fluorescence activated cell sorter (FACS)Calibur cytometer with CellQuest software (BD Biosciences). For in-vivo apoptosis, in order to optimize, first, the detection of apoptosis FAM-FLIVO™ green dye (Immunochemistry Technologies, Bloomington, MN, USA) was used. As a control for the detection of FLIVO in vivo, BALB/c mice were irradiated lethally with 12 Gy gamma irradiation. After 24 h, 8 μg (100 μl) of FAM-FLIVO™ green dye was injected per mouse and left to circulate for 1 h. After 1 h (or other times, not shown), the liver was harvested and isolated cells were analysed by flow cytometry to verify detectability of apoptosis in vivo.

Revealing the mechanisms that underlie the specific expression of these molecules among the different Atezolizumab TEC subpopulations would be useful to understand the molecular and cellular mechanisms for the diversification of TEC subpopulations. Along these lines, recent experiments have shown that mTECs are derived from progenitors that express cTEC-associated molecules [14-16]. Baik et

al. showed that the expression of CD205 in a fraction of TECs was detectable in embryonic day 11 (E11) mouse embryos ([14]; commented on in [17]). When they isolated CD205+CD40– E15 TECs, placed them in reaggregate thymus organ cultures (RTOCs), and thereafter transplanted them under mouse kidney capsules, they found that CD205+CD40– TECs gave rise to CD80+Aire+ mTECs, revealing that embryonic TECs that express the cTEC-associated molecule CD205 contain the potential to differentiate into mTECs [14]. Using transgenic mice that expressed yellow fluorescence protein (YFP) under the control of the IL-7 promoter sequence, in which YFP+ cells represented cells that highly expressed IL-7, Ribeiro et al. in a paper published in 2013 showed that YFP+ TECs isolated selleck compound from E14.5 mice gave rise to CD80+ mTECs in RTOCs, indicating that embryonic TECs that express high levels of IL-7, and so resemble cTECs,

retain the potential to differentiate into mTECs [15]. Ohigashi et al. engineered

mice so that the coding sequence click here of the thymoproteasome β5t gene was replaced with the loxP-specific recombinase Cre, and crossed those mice with CAG-loxP-stop-loxP-EGFP-transgenic reporter mice, in which EGFP would be ubiquitously expressed under the control of the CAG promoter only when the loxP-flanked stop sequences were excised by Cre expression [16]. In those mice, EGFP expression would indicate current and/or past expression of β5t in the cells. It was found that β5t-Cre-mediated EGFP expression was detectable in almost all mTECs, including the Aire+ subpopulation, throughout the ontogeny, indicating that a majority of mTECs, in which β5t expression is not detectable, are derived from β5t-expressing progenitors [16]. Collectively, the three independent reports [14-16] revealed a new stage in the TEC developmental pathways, i.e. bipotent pTECs progress through a stage in which pTECs display molecular signatures associated with cTECs, before then diversifying into mTECs [11]. The new paper by Ribeiro et al. [18] in this issue of the European Journal of Immunology initially provides further support regarding this developmental stage of pTECs that express cTEC-associated molecules. To do so, Ribeiro et al. [18] analyze the expression of the atypical chemokine receptor CCRL1 during mouse ontogeny.