[39] In addition to IL-4 production, we found that production of IL-10 is a striking feature of adipose iNKT cell activation, not

typically observed for iNKT cells in liver or spleen.[3] Together, these studies show that iNKT cells are Th2 polarized compared with iNKT elsewhere, and may have regulatory potential based on their IL-10 production. It is now clear that inflammation plays an important role in obesity and the metabolic syndrome.[47] The resident immune system in adipose tissue is key to this process. The pathological expansion of adipose tissue in obesity is associated with major changes in the adipose immune system, resulting in inflammation, which contributes NVP-BKM120 clinical trial to local and whole body insulin resistance and type 2 diabetes. Recently, many immunometabolic studies have shed light on key players involved in the transformation from a homeostatic anti-inflammatory environment to a pathogenic pro-inflammatory one in obese adipose tissue. All resident immune cells identified so far have been shown to play some role in either the development

or protection from chronic inflammation that drives obesity-induced metabolic disorder.[3, 7, 48-57] This suggests that the adipose immune system is tightly controlled and highly interactive, with any aberrations effecting metabolism, either directly or through the interactions with other immune cells. Recently we, and others, added iNKT cells to the list of key players involved in obesity. In 2009, we reported that iNKT cells were depleted in adipose tissue of obese individuals compared Sotrastaurin in vitro with age-matched lean controls.[2] This defect has also been confirmed by other laboratories[7, 39] and suggests that iNKT cells may play a role in human obesity. There is also a defect in iNKT cells in murine adipose tissue and liver in diet-induced and genetic models of obesity.[3] Our study,[3] and others[39, 57, 58] have highlighted that adipose tissue iNKT cells protect against diet-induced obesity

and glucose intolerance through regulatory cytokine production (Fig. 1). First, it was noted that iNKT-deficient not mice on normal diets were heavier than their wild-type counterparts and displayed an increased tendency towards insulin resistance. This association of iNKT cell deficiency and insulin resistance was a trend that was not significant in mice fed a normal chow diet in our study and in a similar study from Qi and colleagues.[3, 57] However, Boes and colleagues found that this trend was significant, with both CD1d−/− and Ja18−/− mice displaying impaired glucose tolerance and insulin resistance with age on a standard low-fat diet.[7] Second, we, and many groups, noted that iNKT cell numbers in adipose tissue fell in mice fed a high-fat diet (HFD), similar to reduction in iNKT cell number in human obesity.

In those cases known to us, involving treatments which have included prednisone with azathioprine [30], intravenous (i.v.) methylprednisolone with i.v. immunoglobulin (IVIG) [31], methylprednisolone [32] or IVIG alone [4], neurological improvement was variable. selleck chemicals In reality, judging the efficacy of these interventions is difficult, considering the small numbers involved, the different stages of the disease process

at which treatments were started and the different regimens employed, as well as differences in genotype. Such limitations highlight the urgent need to define coherent treatment strategies and monitoring protocols. Below, we outline three approaches to treatment which we think are of immediate interest, although we predict that others will present themselves as our understanding of the pathophysiology of AGS advances. Considering a possible primary role of exposure to type I interferons in AGS pathogenesis, a treatment strategy in which interferon alpha activity is blocked using monoclonal antibodies is worthy of consideration. Clinical trials of such agents, targeted against interferon alpha subtypes Sunitinib in vitro and the type I interferon

receptor, are already being undertaken in the context of systemic lupus erythematosus [33], and the results are eagerly awaited in relation to AGS. What is the source of the nucleic acid inducing the immune disturbance in AGS? Intriguingly, Stetson and colleagues presented data to show that Trex1 can metabolize reverse-transcribed DNA, and that single-stranded DNA derived from endogenous retro-elements accumulates in Trex1-deficient cells [26]. Retro-elements account for close to half of the human genome, and there is evidence to indicate that such elements are more active than recognized previously [34-37]. These observations suggest that mechanisms must exist

to limit such activity, the function of which might plausibly involve TREX1, the RNASEH2 complex, SAMHD1 and ADAR1 (Fig. 3). Considering the above, it is of particular interest that both TREX1 and SAMHD1 have been implicated Niclosamide in the metabolism of nucleic acid derived from exogenous retrovirus. Thus, Lieberman and colleagues have shown that cytoplasmic TREX1 digests non-productive human immunodeficiency virus infection 1 (HIV-1) reverse transcripts in CD4 T cells and macrophages, so that early HIV-1 infection does not trigger a type I interferon response in these cells [38]. Furthermore, the groups of Benkirane [39], Skowronski [40] and Keppler [41] showed that SAMHD1 is a restriction factor for HIV-1 in cells of the myeloid lineage and in CD4+ T cells, and that silencing of SAMHD1 in non-permissive cell lines is associated with a significant accumulation of viral DNA.

Quantitative measures from this second set of simulations were found to correlate extremely well with experimental data obtained from animals treated with an agent that targets

endothelial proliferation (TNP-470). SAR245409 Conclusion:  Our direct combination and comparison of in vivo longitudinal analysis (over time in the same animal) and mathematical modeling employed in this study establishes a useful new paradigm. The virtual wound created in this study can be used to investigate a wide range of experimental hypotheses associated with wound healing, including disorders characterized by aberrant angiogenesis (e.g., diabetic models) and the effects of vascular enhancing/disrupting agents or therapeutic interventions such as hyperbaric oxygen. “
“We sought to test the hypothesis that turmeric-derived curcuminoids limit reperfusion brain injury in an experimental model of stroke via blockade of early microvascular inflammation during reperfusion. Male Sprague Dawley rats subjected to MCAO/R were treated with turmeric-derived curcuminoids (vs. vehicle) 1 hour prior to reperfusion (300 mg/kg ip). Neutrophil adhesion to the cerebral microcirculation and measures of neutrophil and endothelial Selleckchem AZD1152-HQPA activation were assayed during

early reperfusion (0–4 hours); cerebral infarct size, edema, and neurological function were assessed at 24 hours. Curcuminoid effects on TNFα-stimulated human brain microvascular endothelial cell (HBMVEC) were assessed. Early during reperfusion following MCAO, curcuminoid treatment decreased neutrophil rolling and adhesion to the cerebrovascular endothelium by 76% and 67% and prevented >50% of the fall in shear rate. The increased number and activation state (CD11b and ROS) of neutrophils were unchanged by curcuminoid treatment, while increased cerebral expression of TNFα and ICAM-1, a marker of endothelial activation, were blocked by >30%. Curcuminoids inhibited NF-κB activation and subsequent ICAM-1 gene expression in HBMVEC. Turmeric-derived curcuminoids limit reperfusion injury in stroke by preventing

neutrophil adhesion to the cerebrovascular microcirculation and improving shear rate by targeting the endothelium. Oxalosuccinic acid “
“Angiotensin II causes potent increases in systemic and local pressure through its vasoconstrictive effect. Despite the importance of angiotensin II for local blood flow regulation, whether angiotensin II regulates the pancreatic islet microcirculation remains incompletely understood. We hypothesized that angiotensin II directly regulates the pancreatic islet microcirculation and thereby regulates insulin secretion. The aims of this study were to develop a new technique to visualize pancreatic islet hemodynamic changes in vivo and to analyze changes in islet circulation induced by angiotensin II or an angiotensin type 1 receptor blocker.

Higher FGF23 concentrations have been consistently associated with increased risk of mortality at all stages of CKD, independent of traditional renal and cardiovascular risk factors.[91-94] In animal studies FGF23 excess as a result of direct intracardiac administration of a mutant FGF23 (and where klotho is absent) has been shown to lead to left ventricular hypertrophy and provides a plausible mechanism of direct cardiac injury at the high concentrations observed in advanced disease.[95] The significance that these experiments were carried out with mutant FGF23 resistant to furin KPT-330 manufacturer protease digestion is not known. However, supporting independent links between FGF23

and cardiovascular outcomes and mortality is the integrity of such associations after adjusting for phosphate, PTH and vitamin D levels.[91-94] It has yet to be established whether specifically lowering FGF23 or antagonizing its action would yield clinical benefit. Indeed, antagonizing FGF23 with a specific antibody increased vascular calcification and mortality in animals with renal impairment.[96] The downregulation of klotho expression in tissues where it is expressed has been linked to enhancement of the klotho-independent effects of FGF23 in other tissues. One explanation is that with less

binding to the klotho–FGFR IWR-1 cell line complex, more FGF23 is left in the circulation to bind ‘off-target’ to other FGFR, where specificity to the receptor is low, yet ligand present in excess so causing activation of other low specificity FGFR at non-physiological sites. A consistent finding in CKD is the overall decrease in mKl expression in the kidney, parathyroid glands and vasculature.[97] Although human studies Sirolimus clinical trial of mKl have been

limited due to difficulty in obtaining tissue to determine expression, there appears to be good evidence of reduced kidney mKl expression in animal CKD models.[31, 98] A low level of sKl in plasma and urine of mice with CKD has also been reported.[31] Human studies reporting on associations between circulating sKl and renal function have been capricious even using the same assay (Table 1). Seiler et al. reported no correlation between sKl levels and renal function[43] while other investigators report an increase in sKl with declining GFR.[49, 50, 55] More than half of the human studies in patients with CKD however have documented a reduction in sKl levels with reduced GFR.[39-41, 52-54] The aforementioned issues with assay performance may underpin the apparent discordant results, but may also relate to differences in study setting or simply reflect intricacies of klotho metabolism, which as yet we do not understand. Nonetheless, reductions seen in mKl suggest a relative deficiency of klotho in CKD.

Three type strains [M. abscessus (ATCC 19977T), M. massiliense (KCTC 19086T= CIP 108297T) and M. bolletii (KCTC 19281T= CIP 108541T)], and 101 M. abscessus-M. chelonae group clinical isolates (M. abscessus, 46; M. massiliense, 49; M. bolletii, two; and M. chelonae, four strains) were used in the present study. In addition to the 85 strains that were used in a previous report (7), 16 strains (Inje collection) were newly included. Mycobacteria were cultivated on Ogawa media or blood agar plates at 37°C under 5% CO2

for 4 days, after which they were subjected to clarithromycin susceptibility testing and sequence analysis. Total DNAs were extracted from cultured colonies using the bead beater-phenol extraction method (17) and used as templates for PCR. The following primer pairs were used: ermF (5′-GAC CGG GGC CTT CTT CGT GAT-3′) and ermR1 (5′-GAC TTC CCC GCA CCG selleck chemicals llc ATT CC-3′) for the whole erm(41) (GenBank accession No. CU458896) and primers 19 (5′-GTA GCG AAA TTC CTT GTC GG-3′) and 21 (5′-TTC CCG CTT AGA TGC TTT CAG-3′) for 23S rRNA gene (18). Template DNA (approximately 50 ng) and 20 pmol of each primer were added to a PCR mixture tube (AccuPower PCR PreMix; Bioneer, Daejeon, Korea) that contained 1 unit of Taq DNA polymerase, 250 μM deoxynucleotide triphosphate, 10 mM Tris-HCl (pH 8.3), 10 mM KCl, 1.5 mM MgCl2, and gel loading dye. The final volume was

then adjusted to 20 μl with distilled water, after which the reaction mixture DNA Damage inhibitor was amplified using a model 9700 Thermocycler (Perkin-Elmer Cetus, Norwalk, NJ, USA). The PCR products were purified using QIAEX II gel extraction Inositol monophosphatase 1 kits (Qiagen, Hilden, Germany), and were then sequenced directly using forward and reverse primers on an Applied Biosystems automated sequencer (model 377) using BigDye Terminator Cycle Sequencing kits (Applied Biosystems, Warrington, UK). Both strands were sequenced as a cross-check. The resultant 23S rRNA gene and erm(41) sequences were aligned using ClustalW in the MEGA 4.0 (19) and the sequence similarities were analyzed using MegAlign software (DNAStar, Madison, WI, USA) (20). Mycobacterium tuberculosis erm(37) and M. abscessus erm(41) were retrieved from the

GenBank and used to compare with newly determined sequences. The newly determined erm(41) sequences of M. massiliense (accession no. FJ358487 to FJ358490), M. bolletii (accession no. FJ358491), and M. abscessus (accession no. FJ358483 to FJ358486) were deposited in GenBank. M. abscessus (ATCC 19977T), M. massiliense (KCTC 19086T= CIP 108297T), and M. bolletii (KCTC 19281T= CIP 108541T), which are known for their susceptibility to clarithromycin, were used as controls. The MIC of clarithromycin were determined in microtiter plates (21) using the broth dilution method with slight modification as described previously (7). To prepare a stock solution, clarithromycin (Boryung, Seoul, Korea) was solubilized in distilled water with glacial acetic acid (2 μl/ml) (22).

Methods  CD1d-bearing choriocarcinoma cells were used in flow cytometry and immunoprecipitation experiments. CD1d-mediated cytokine induction JNK inhibitor cost was assessed using antibody cross-linking. Cytokine production during co-culture of decidual lymphocytes with CD1d-bearing cells was also examined. Results  Trophoblast surface-expressed CD1d forms a complex with PS-bound β2GP1. Anti-β2GP1 mAb cross-linking causes IL12p70 release from CD1d-bearing cells. IL12p70 release from CD1d-bearing trophoblast

cells was also induced during co-culture with human decidual lymphocytes. The addition of anti-β2GP1 mAb to co-cultures resulted in a three-fold increase in IL12p70 secretion. IFNγ secretion from decidual lymphocytes was also induced during co-culture with anti-β2GP1 mAbs. Conclusions  β2GP1-dependent IL12 release from CD1d-bearing trophoblast in the presence of aPL may link the antiphospholipid syndrome to pregnancy loss via an inflammatory mechanism. “
“Type 1 diabetes is an autoimmune disease characterized by destruction of the pancreatic islet beta cells that is mediated primarily by

T cells specific for beta cell antigens. Insulin administration prolongs the life of affected individuals, but often fails to prevent the serious complications that decrease quality of life and result in significant morbidity https://www.selleckchem.com/products/MK-1775.html and mortality. Thus, new strategies for the prevention and treatment of this disease are warranted. Given the important role of dendritic cells (DCs) in the establishment of peripheral T cell tolerance, DC-based strategies are a rational and exciting avenue of exploration. DCs employ a diverse arsenal to maintain

tolerance, including Liothyronine Sodium the induction of T cell deletion or anergy and the generation and expansion of regulatory T cell populations. Here we review DC-based immunotherapeutic approaches to type 1 diabetes, most of which have been employed in non-obese diabetic (NOD) mice or other murine models of the disease. These strategies include administration of in vitro-generated DCs, deliberate exposure of DCs to antigens before transfer and the targeting of antigens to DCs in vivo. Although remarkable results have often been obtained in these model systems, the challenge now is to translate DC-based immunotherapeutic strategies to humans, while at the same time minimizing the potential for global immunosuppression or exacerbation of autoimmune responses. In this review, we have devoted considerable attention to antigen-specific DC-based approaches, as results from murine models suggest that they have the potential to result in regulatory T cell populations capable of both preventing and reversing type 1 diabetes. Type 1 diabetes is an organ-specific autoimmune disease characterized by progressive loss of the insulin-producing beta cells that reside within the pancreatic islets [1].

Experiment 2 assessed the role of ODVs in learning word–object associations. Forty infants aged 11.5 months played with a novel object and received a label either contingently on an ODV or on a look alone. Only infants who received labels in response to an ODV learned the association. Taken together, the findings suggest that infants’ ODVs signal a state of attention Ku-0059436 purchase that facilitates learning. “
“The ability to distinguish phonetic variations in speech that are relevant to meaning is essential for infants’ language development. Previous

studies into the acquisition of prosodic categories have focused on lexical stress, lexical pitch accent, or lexical tone. However, very little is known about the developmental course of infants’ perception of linguistic intonation. In this study, we investigate infants’ perception of the correlates of the statement/yes–no question contrast in a language that marks this sentence type distinction only by prosodic means, European Portuguese (EP). Using a modified version of the visual habituation paradigm, EP-learning infants at 5–6 and 8–9 months were able to successfully discriminate selleck screening library segmentally varied, single-prosodic word intonational phrases presented with statement or yes–no question intonation, demonstrating that they are sensitive to the prosodic

cues marking this distinction as early as 5 months and maintain this sensitivity throughout the first year. These results suggest the presence of precocious discrimination abilities for intonation across segmental variation, similarly to previous reports for lexical pitch accent, but unlike previous findings for word stress. “
“Most infants with more than 6 weeks of crawling experience completely avoid the deep side of a visual cliff

(Campos, Bertenthal, & Kermoian, 1992; Gibson & Walk, 1960). However, some experienced crawlers do move onto the transparent surface suspended several feet above the ground. An important question is whether these nonavoiders ALK inhibitor lack wariness of heights or whether they have a qualitatively different way of showing their wariness than do avoiders of the deep side. The current study addressed this question by measuring heart rate (HR) acceleration upon being lowered on the deep and shallow sides of the visual cliff, latency to crawl toward the mother, and tactile exploration of the cliff surface. Nonavoiders and avoiders had indistinguishable patterns of HR acceleration, showing greater HR acceleration when lowered onto the deep than when lowered onto the shallow side of the cliff. Nonavoiders also showed more tactile exploration and longer latencies than did a comparable group of infants tested on the shallow side. This study illustrates how the same emotion, wariness of heights, can be shown by qualitatively different behaviors, all serving the same function of protecting the individual from falling over a drop-off.

However, this has not been shown in allogeneic immune systems. Here, in vitro, we analysed the effects of these five drugs on DC maturation and functions, selleck screening library including morphology, cytokine production, expressions of MHC class II, co-stimulatory molecules and Toll-like receptor (TLR)-4, and their allostimulatory capacity. We found that AZM significantly inhibited DC maturation and functions, including allogeneic responses. The present study suggests an attractive role for pharmacological therapy as a means of generating

DCs with tolerogenic/regulatory properties. AZM may have potential as a new therapeutic drug for controlling allograft immunity, such as acute graft-versus-host disease and graft rejection in organ transplantation. Female C57BL/6 (H-2 Kb) mice and BALB/c (H-2 Kd) mice aged 6–12 weeks were purchased from Japan SLC, Inc. (Shizuoka, Japan). Institutional approval was obtained for all animal experimentation. Fluorescein isothiocyanate (FITC)- or phycoerythrin (PE)-conjugated monoclonal antibodies (mAbs) used to detect cell surface expression of CD3, CD4, CD11c, CD40, CD80, CD86, MHC class II, and TLR-4-message digest 2 (MD2) by flow cytometry, as well as isotype-matched

control mAbs, were purchased from BD Pharmingen and eBioscience (San Diego, CA, USA). RPMI-1640 supplemented with 10% fetal calf serum (FCS), 5 × 10−5 m 2-mercaptoethanol (ME) and 10 mm HEPES was used as the culture medium. Bone marrow (BM)-derived DCs

were generated as described elsewhere [23,24], with minor modifications. Briefly, BM cells flushed from tibias and femurs of BALB/c mice were seeded GSI-IX purchase at 2 × 106 cells onto a six-well culture plate in culture medium supplemented with 20 ng/ml recombinant murine granulocyte–macrophage colony-stimulating factor (GM-CSF) (Kirin Brewery Co., Gunma, Japan). The culture medium was changed every 2 days. Loosely adherent clustered cells were used on day 6 as immature DCs (im-DCs). The purity of im-DCs was routinely Dapagliflozin > 85%, as confirmed by dual positivity for MHC class II and CD11c. Vit. D3 (Sigma, St Louis, MO, USA), ACE inhibitor delapril (Takeda Co. Ltd, Osaka, Japan), PPAR-γ activator troglitazone (Sankyo Co., Tokyo, Japan), clarithromycin (CAM) (Taisho Pharmaceutical Co., Tokyo, Japan) or AZM (Pfizer Inc., Groton, CT, USA) as an NF-κB inhibitor was added to culture wells to the indicated final concentrations at various times. We tested these NF-κB inhibitors at several concentrations to generate BM-derived DCs. The final concentrations of NF-κB inhibitors, except Vit. D3, chosen for the study were 10 times their physiological concentrations shown to have therapeutic effects on several human diseases [25–28]. Vit. D3 (10 nm) [14] was added to culture wells on days 0, 2, 4 and 6. Troglitazone (10 µm), delapril (40 µg/ml) and CAM (20 µg/ml) were added every day (days 0–6).

5 μg/animal 18; in this study we used RO4929097 the CAF01 adjuvant, where the optimal dose for TB10.4 was found to be 5 μg/animal (and changing the dose did not affect the epitope pattern (data not shown). We next examined whether the secretion of IFN-γ induced by some of the peptides reflected an increased number of T cells specific for this peptide, or merely an increased secretion of IFN-γ. Mice were immunized with BCG or TB10.4, or infected with virulent M.tb. At week 4 post immunization or infection, splenocytes were isolated from the three groups and stimulated in vitro with the nine overlapping TB10.4 peptides. The number of T cells specific for one peptide was analyzed

by IFN-γ ELISPOT, and the results clearly demonstrated a correlation between the number of epitope-specific IFN-γ-producing cells analyzed by ELISPOT and the concentration of epitope-specific IFN-γ in the supernatants analyzed by ELISA (Fig. 1A and B). Thus, clonal expansion of T cells specific for certain epitopes following immunization or infection resulted in the IFN-γ production seen in Fig. 1A, and the level of cytokine produced in response to peptide stimulation

corresponded with the number of specific IFN-γ-producing T cells seen in Fig. 1B. To determine whether CD4+ or CD8+ T cells were responsible for the epitope recognition, mice were immunized with TB10.4, BCG or M.tb infection as described above. PBMC from BCG-immunized or M.tb-infected mice stimulated

with each of peptides P1–P9, and selleck chemical analyzed by flow cytometry, showed that P8 and P9 were both recognized by CD4+ T cells following BCG-immunization and M.tb infection (Fig. 2), whereas P1 and P2 were only recognized following M.tb infection and primarily by Atorvastatin CD8+ T cells (Fig. 2). Regarding the CD4+ T-cell-mediated response, however, only the live vectors BCG or M.tb induced CD4+ T cells recognizing epitopes within P8 and P9, whereas CD4+ T cells specific for P3 were only seen after TB10.4/CAF01 (Fig. 2). Thus, we conclude that with regard to TB10.4, live vectors such as BCG (and M.tb) induce expansion of CD4+ T cells specific for one epitope pattern, whereas recombinant protein in CAF01 induce a different CD4+ T-cell-specific pattern against the same protein. TB10.4 expressed in mycobacteria may be subjected to post-translational modification. This could in turn affect the processing of the protein. To study this, we first examined whether native TB10.4 expressed and purified from mycobacteria would induce a similar epitope pattern as recombinant TB10.4 expressed and purified from Escherichia coli. Mice were immunized with either recombinant (E.coli) or native TB10.4 (Mycobacterium smegmatis), both in CAF01. Four weeks after the third immunization, PBMC were stimulated in vitro with peptides P1–P9, and IFN-γ was secretion measured by ELISA.

In conclusion, the difference in therapeutic effect between LGG wild-type and dltD mutant in vivo suggests a role for the cell surface of the wild-type LGG strain in determining its therapeutic efficacy. Interestingly, these results with the

LGG dltD mutant show the potential of modifying the cell surface of probiotic strains for better treatment of IBD with probiotics. Combining these modified probiotic strains with the concept of ‘designer probiotics’[62] seems to be appealing for the future. One example of such a ‘designed’ strain is the IL-10-secreting Lactococcus lactis strain that shows potential in treatment of IBD [63,64]. Further in vitro studies are required to reveal the molecular mechanisms underlying the beneficial effects of this altered cell surface.

I.C. holds a PhD grant of the Neratinib manufacturer Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT–Vlaanderen). D.B. holds a senior researcher grant of FWO–Vlaanderen. Additionally, this work was supported partially by the FWO–Vlaanderen through project G.0236·07. We thank K. Geboes for helpful selleck chemicals discussions regarding the set-up of the animal experiments. The authors also gratefully acknowledge L. Ophalvens for excellent technical assistance. We thank the anonymous reviewers for their helpful comments and suggestions. The authors declare no conflicts of interest. “
“The Melan-A/MART-126-35 antigenic peptide is one of the best studied human tumor-associated antigens. It is expressed in healthy melanocytes and malignant melanoma and is recognized by CD8+ T cells in the context of the MHC class I molecule HLA-A*0201. While an unusually large repertoire of CD8+ T cells specific for this antigen has been documented, the reasons for its generation have remained

elusive. In this issue of the European Journal of Immunology, Pinto et al. [Eur. J. Immunol. 2014. 44: 2811–2821] uncover one important mechanism Dapagliflozin by comparing the thymic expression of the Melan-A gene to that in the melanocyte lineage. This study shows that medullary thymic epithelial cells (mTECs) dominantly express a truncated Melan-A transcript, the product of misinitiation of transcription. Consequently, the protein product in mTECs lacks the immunodominant epitope spanning residues 26–35, thus precluding central tolerance to this antigen. In contrast, melanocytes and melanoma tumor cells express almost exclusively the full-length Melan-A transcript, thus providing the target antigen for efficient recognition by HLA-A2-restricted CD8+ T cells. The frequency of these alternative gene transcription modes may be more common than previously appreciated and may represent an important factor modulating the efficiency of central tolerance induction in the thymus.