01). Conclusion: Our studies confirmed the role of Gd-IgA1-IgG IC in the pathogenesis of IgAN and induction of proteinuria and hematuria.

Furthermore, the Gd-IgA1-IgG IC may bind to glomerular endothelial cells and induce release of pathogenic cytokines and chemokines. SUZUKI HITOSHI1, SUZUKI YUSUKE1, MAKITA YUKO1, YANAGAWA HIROYUKI1, JULIAN BRUCE A2,3, NOVAK JAN3, TOMINO YASUHIKO1 1Division of Nephrology, Department of Internal Medicine, Juntendo University Faculty of Medicine; 2Departments of Medicine, https://www.selleckchem.com/products/ly2157299.html University of Alabama at Birmingham; 3Departments of Microbiology, University of Alabama at Birmingham Introduction: IgA1 in circulating immune complexes and mesangial deposits of patients with IgA nephropathy (IgAN) is aberrantly glycosylated, galactose-deficient in O-glycans (Gd-IgA1), and is bound to anti-glycan IgG/IgA autoantibodies. However, the origin of cells producing Gd-IgA1 and the autoantibodies is not certain. Upper respiratory tract infections and tonsillitis are frequently associated with clinical presentation and exacerbation of IgAN, suggesting a link with disease pathogenesis. In some patients, tonsillectomy and glucocorticoids (TSP) may slow disease progression LY2606368 cost in early clinical stages. Therefore, we assessed whether

tonsillar cells produce Gd-IgA1 or anti-glycan autoantibodies. Methods: Tonsillar

cells obtained from 29 patients with IgAN were cultured 72 hours. Gd-IgA1 and anti-glycan IgG secreted by these cells were measured by ELISA. Proteinuria and hematuria, and serum levels of Gd-IgA1, Gd-IgA1-specific IgG and IgA, and IgG-IgA immune complexes (IC) were measured before and Chlormezanone after TSP. Results: Proteinuria and hematuria improved after TSP (P < 0.05). Eighteen of 29 patients had proteinuria less 0.3 g/g and 5 red blood cells/HPF after TSP (Remission group). Eleven patients did not clinically improve (non-Remission group). Serum levels of Gd-IgA1, Gd-IgA1-specific autoantibodies, and IgG-IgA IC decreased during glucocorticoid therapy after tonsillectomy (P < 0.01). The rates of decrease in the levels of Gd-IgA1, Gd-IgA1-specific antibodies and IgG-IgA IC were greater in the Remission group (P < 0.01). Tonsillar cells from Remission group produced more Gd-IgA1 and anti-glycan IgG than those from non-Remission group (P < 0.01). Conclusion: Tonsillar cells may contribute to the circulating Gd-IgA1 and anti-glycan IgG in patients with IgAN. These biomarkers may be useful for guiding therapy of IgAN. YAMADA KOSHI1,2, HUANG ZHI-QIANG1, RASKA MILAN1,3, REILY COLIN R.1, SUZUKI HITOSHI1,2, MOLDOVEANU ZINA1, KIRYLUK KRZYSZTOF4, SUZUKI YUSUKE2, TOMINO YASUHIKO2, GHARAVI ALI G.4, WILLEY CHRISTOPHER D.1, JULIAN BRUCE A.

Furthermore, experimental data generated using HVC-infected chimpanzees demonstrate that the miR-122 antisense locked

nucleic acid (LNA) SPC3649 is able to clear both the HCV 1a and the 1b genotypes AZD2281 solubility dmso 40. These data hold much promise for novel anti-HCV therapies. In the case of HCV-induced inflammation, if the target site for miR-155 in the TNF 3′ UTR was to be blocked, this could provide a new strategy to limit TNF expression and TNF-associated activities. Another approach could be to specifically boost the effect that miR-21 has on PDCD4 and thus also generate an anti-inflammatory effect. These types of studies are worth pursuing, since targeting both miR-155 and miR-122 would effectively boost the resolution of inflammation. A second example where the targeting of miRNAs regulated by TLRs might hold promise is in myelodysplastic syndrome (MDS). MDS results from selleck the ineffective production of myeloid cells from stem cells in the BM and arises at the stage of primitive CD34+ hematopoietic stem/progenitor cells due to ineffective hematopoiesis. One of the most common forms is the 5q-syndrome, which results in the deletion of a segment on chromosome 5, long-arm position 32 (5q32) 41–43. The commonly deleted region at 5q32 contains 40

genes and a number of miRNAs, including miR-145 and miR-146a. Starczynowski et al. 41 found that 5q-MDS individuals had low levels of miR-145 and miR-146a, thereby confirming their deletion 41. A key target for miR-145 is known to be the adapter Mal, which is required for signaling by TLR2 and, especially, TLR4 Cell press 42. As mentioned in the miR-146 section, miR-146 targets IRAK1 and TRAF6. The knockdown of miR-145 and miR-146a or, in particular, the enforced expression of TRAF6 in hematopoietic stem/progenitor cells transplanted into mice results in

thrombocytosis, neutropenia, and megakaryocytic dysplacia 41. These changes lead to the induction/overexpression of pro-inflammatory cytokines, such as IL-6, leading to chronic inflammation, which again appears to promote tumorogenesis in this disease. Other studies, e.g. 43, have failed to find a correlation between 5q-MDS and downregulation of miR-145–miR-146a, however; hence further analysis is needed. Nonetheless, blockade of the Mal/TRAF6 pathway could prove to be therapeutically useful in MDS. Clearly, the targeting of miRNAs for therapeutic purposes is at an early stage; however, given the roles of miR-146a, miR-155, and miR-21 in the control of inflammation, and, in particular, in macrophage function, they remain of interest for future drug development. An important consideration is in vivo validation, and Table 1 summarizes this aspect for these miRNAs. As summarized in Table 1, deletion of miR-155, miR-146, and miR-21 has serious consequences in mice, e.g. autoimmune disease.

Tumour-associated B7-H3 was unlikely to be involved in an initial antigen-priming phase of CD8+ T-cell responses. A similar observation has been reported using B7-H3-transfected P815 cells and adoptive transfer in a P1A-specific CTL model system.25 B7-H3 expression on P815 tumour Vincristine cells enhanced CD8-mediated tumour immunity by amplifying local expansion of tumour-specific CTL in the absence of professional antigen-presenting cells. Unfortunately, the P815 cells used in our study lacked a P1A tumour antigen so we used OVA-specific TCR-transgenic CD8+ (OT-I CD8+) T cells and an OVA-expressing

tumour (E.G7) cell system to assess antigen-specific CTL responses. Another report also demonstrated enhanced tumour immunity by B7-H3 introduction into Colon 26 colon carcinoma cells.26 IFN-γ production from splenic CD8+ T cells of tumour-bearing mice was enhanced by co-culture with B7-H3+ tumour cells. In both reports, B7-H3-introduced tumours were not completely rejected in all individuals and some mice developed large tumours and died. Our results also showed a failure of complete tumour rejection. Although we have not observed this in parallel studies, it seems that

the effects of introducing B7-H3 is not as strong as those of CD80, CD86, 4-1BBL or GITRL both in vitro and in vivo.35,36,40,43–45 We also examined tumour vaccine effects of B7-H3-transduced tumours following Selleckchem Saracatinib several injections of B7-H3/SCCVII after pre-inoculation of live parental tumours; however, there was no effect on tumour growth Chloroambucil (data not shown). These observations are consistent with a previous report on B7-H3/P815 tumour vaccine effects.25 It is likely that the reason for the limited effect of B7-H3-transduced tumour cells was the few or no enhancing effects of

B7-H3 during the priming phase. The de novo induction of regulatory co-stimulatory ligands like B7-H1 and B7-H4 in tumour cells and others may override the effects of B7-H3-mediated anti-tumour immunity.22 The major reason for dominant involvement of CD8+ T cells in B7-H3-enhanced immunity could be the result of counter-receptor expression. In the steady state, TLT-2 is clearly expressed on splenic CD8+ T cells, whereas TLT-2 on CD4+ T cells is either weak or null (Fig. S2 and ref. 28). Nevertheless, we observed preferentially higher anti-CD3 mAb-induced re-directed cytotoxicity of CD4+ T cells against both parental P815 and B7-H3/P815 cells (Fig. 1). We have previously shown that the anti-CD3 mAb-induced re-directed cytotoxicity was greatly dependent on the Fas–Fas ligand pathway.33 In fact, the re-directed cytotoxicity of CD4+ T cells against P815 and B7-H3/P815 cells was efficiently inhibited by blocking anti-Fas ligand mAb (data not shown). CD4+ T cells rapidly increased TLT-2 expression by anti-CD3 mAb stimulation alone (Fig.

To assess the role of bacterial and viral stimuli in Th2 differentiation, CD4+ T cells from cord blood were assayed in an MLR together with different strains of bacteria and virus. To compare the effect of the different microbes on cytokine secretion, we assessed the relative change in cytokine production for each microbe. The relative change was calculated using the amount of cytokine produced in MLR cultures containing a specific microbe, divided by the cytokine amount secreted in an MLR lacking microbe. All enveloped viruses tested (coronavirus, CMV, HSV-1, influenza virus and morbillivirus)

downregulated the IL-13 responses in cord blood cocultures (Fig. 3E,F). The non-enveloped AP24534 in vitro viruses, adenovirus and poliovirus had no effect on the IL-13 production in cord MLR cultures using either pDC (Fig. 3F) or mDC (Fig. 3E) from cord blood as antigen presenting cells. Neither did any of the bacteria reduce the IL-13 responses. Instead, S. aureus stimulated pDC increased the IL-13 production in responding CD4+ cord T cells (Fig. 4F). We were not able to document any significant inhibitory effects on the IL-5 production by the virus, most likely due to the very low initial production selleck screening library of this

cytokine (not shown). The effect of viral and bacterial stimuli on Th1 cytokine secretion was assessed using cord CD4+ T cells cocultured with allogenic pDC or mDC from cord blood. Both bacteria and virus could affect IL-2 and IFN-γ secretion by cord CD4+ T cells (Figs 3 and 4). Influenza virus was the most Terminal deoxynucleotidyl transferase efficient inducer of IL-2 and significantly enhanced the responses in cord CD4+ T cells exposed to cord pDC (Fig. 3B) and to cord mDC (Fig. 3A). Influenza virus also enhanced the IFN-γ responses, but only in cord T cell/mDC cultures (Fig. 3C). None of the other viruses tested affected the IL-2 or IFN-γ production in these cocultures except CMV that reduced the IL-2 production from cord CD4+ T cells and pDC cocultures (Fig. 3B), that is from the

cells with the highest initial IL-2 production (Fig. 2A). Staphlococcus aureus was the only bacteria that enhanced IL-2 responses by cord CD4+ T cells exposed to both mDC (Fig. 4A) and pDC (Fig. 4B). Staphlococcus aureus was also a potent inducer of IFN-γ responses in both pDC and mDC stimulated cord CD4+ T cells (Fig. 4C,D). To assess innate cytokine secretion in cord DC, pDC and mDC from cord blood were stimulated with different strains of bacteria and virus together with allogenic cord CD4+ T cells. We found that all Gram-positive bacteria, but not E. coli or any of the viruses, promoted an IL-12 p40 response in MLR cultures with mDC (Fig. 5A,C) but not with pDC (not shown). The increase in IL-12 production in C. difficile stimulated cell cultures was, however, not statistically significant, even though there was a strong trend (Fig. 5A). We also analysed the ability of virus and bacteria in evoking an IFN-α response in pDC.

3). Of the two immune-mediator genes that were quantified (IL18R1, IL33), only IL18R1 expression was reduced significantly in the AA group when compared to the SS group at the 28-day post-surgery time-point (Fig. 4). Utilizing the first murine appendicitis model (developed by us), we have shown previously that

although appendicitis alone or appendectomy alone or no intervention alone were not protective, appendicitis followed by appendectomy (AA) provided significant protection against subsequent experimental colitis [16]. We chose the distal-most colonic samples carefully, avoiding the caecum see more and the rest of the colon, not only for the obvious reason of pathological relevance, but also to minimize bacterial contamination and severely acute inflammatory changes in the acutely inflamed caecum. We have also avoided delving into minutiae regarding specific immunological systems, such as the markedly suppressed T helper type 2 (Th17) system in AA which will be expounded in another manuscript, for the sake of space, brevity and focus. We used gene-set enrichment analysis (GSEA) to elucidate the pathways involved in this protective effect. Distal colonic expression of 266 gene-sets was significantly up-regulated in AA group samples and the study was Selleckchem LY2109761 validated by quantitative RT–PCR of 14 selected genes. However, time–course experiments involving these genes displayed down-regulation of these genes over a period of 28 days in both SS and

AA groups. Many key immunological, apoptosis-related and cellular function-associated gene-sets involved in the protective effect of AA in experimental colitis were identified. The up-regulated gene-sets not known to be involved directly in immunity include those participating in cellular cytoskeleton, apoptosis, cell cycle, selleck growth and growth factors, non-immune development and differentiation, enzyme activity and regulation, protein metabolism, injury, healing and angiogenesis, reactive species stress-related, malignancy and intervention-related and transcription factors. Up-regulated gene-sets known to play well-established roles in immunity include those participating in antigen processing,

cellular adhesion, extracellular matrix and receptor interactions, nuclear factor-kappaB (NF-κB)-related pathways, cellular signalling, immune system development and differentiation, injury, healing and angiogenesis, responses to pathogens, chemokine and cytokine-related pathways, interferon and other immune-factor-related or -induced pathways. The IBD-associated genes tnfsf10, SLC22A5, C3, ccr5, irgm, and ptger4 were up-regulated and ccl20 gene (also IBD-associated) was decreased in AA mice 3 days after surgery. Of immunologically relevant IBD genes that were modulated, tnfsf10[36] encodes a cytokine belonging to the tumour necrosis factor (TNF) ligand family, which binds to several members of the TNF receptor superfamily and triggers activation of MAPK8/JNK and caspases.

Several clinicopathological studies have provided evidence that the prognosis of patients with MB depends on the histological tumor type. For example, the survival period for patients with anaplastic/large cell MB is shorter than that for patients with CMB.[2-7] Patients with MBEN are expected to have a better outcome

than patients with other types.[8, 9] On the other hand, it is still RG7420 solubility dmso unclear whether DNMB-type histology predicts a favorable outcome. Several investigations have indicated that patients with DNMB survive longer than those with CMB;[10-16] however, others have provided evidence to the contrary.[16, 17] A recent breakthrough in understanding the pathomechanisms of MB has been the discovery of the Sonic Hedgehog (Shh) signaling pathway. Shh is considered to regulate growth and patterning during development

of the cerebellum,[18] and plays an essential role in the tumorigenesis of a subset of MB.[19, 20] Moreover, Shh plays an integral role in a wide variety of developmental processes in vertebrates, and in the development of carcinomas in various organs (Fig. 1A,B). The Shh ligand binds to patched (PTCH) receptors, and inhibits BI-2536 activity against Smoothened on the cytoplasmic membrane. In the on-state, Gli1 and Gli2, the Gli activators in mammals, are produced in the cytoplasm and transported into the nucleus, where various target oncogenes against Shh, including Cyclin D, Cyclin E, Myc, Gli1 and PTCH, are transcribed (Fig. 1B). In the off-state, by contrast, a Gli repressor, Gli3, is produced in the cytoplasm and transported into the nucleus,[21] where it inhibits transcription

of the target oncogenes and promotes normal differentiation (Fig. 1A). It is still unclear whether the expression of the Shh signaling pathway influences the differentiation of MB cells, and consequently affects the outcome of patients with MB. The present study attempted to determine whether expression of Gli3 contributes to neuronal differentiation of the Megestrol Acetate tumor cells and to a favorable outcome for patients with MB. We reviewed the medical records of 32 consecutive patients (19 males, 13 females: age at onset, mean ± SD = 9.7 ± 5.8 years) with pathologically confirmed MB who were referred to the Brain Research Institute, University of Niigata, Japan, between 1982 and 2010. All the patients had undergone maximum possible tumor resection, followed by 30.6 to 36.0 Gy of craniospinal irradiation with a 18.0–23.4 Gy posterior fossa boost. Patients (n = 6: five male, one female: age 8.2 ± 7.2 years) who were admitted to our hospital between 1982 and 1991 had received radiotherapy only. On the other hand, a large proportion of the patients included in the present study (n = 23: 12 males, 11 females: age 9.8 ± 4.

These differences should favour the binding of the IL-2 to cellular receptors. Consistent Wnt mutation with this idea, we found that the CTLL-2 cell line, an IL-2-dependent T-cell line which expresses high levels of the alpha chain characteristic of the high-affinity receptor (αβγ)

on activated T cells, can compete for the IL-2 released after cleavage of the fusion protein as seen in Figs 2–5. Given the attenuated bioactivity of the intact fusion protein in vitro, an important issue is whether the fusion proteins would have any biological activity in vivo. We examined the activity of a fusion protein on tumour growth on the omentum,32,38 a common site of intraperitoneal tumour growth and metastases. This model system has a number of features that make Ibrutinib ic50 it attractive for the initial testing

of the protease-activated cytokine strategy. The peritoneal cavity, particularly in the context of growing tumours, contains a number of immunosuppressive cells and factors often found at other tumour sites. However, there are also a variety of leucocytes in the peritoneal fluid as well as a number of immune aggregates or milky spots on the omentum, which function in many respects like lymph nodes. The milky spots are particularly intriguing because they contain organized collagen structures that appear to aid in tumour cell attachment and they are also highly vascular and pro-angiogenic, which promotes tumour cell growth.32,38 However, they also contain many immune effectors including macrophages, B cells, T cells and NK cells that in principle could be activated in an anti-tumour response (48 reviewed in ref. 32). Despite these immune cells, tumours

typically grow rapidly on the milky spots.38,49,50 Tumours growing on the omentum express high levels of MMPs as a result of their intrinsic production as well as contributions by host cells including macrophages. Hence, this experimental model of tumour metastases has a number of technical and conceptual features that make it amenable for testing the protease-activated cytokine strategy. We showed that the fusion protein significantly Dolutegravir reduced tumour growth on the omentum (Fig. 6) illustrating that it can have biological activity in vivo. Future studies are needed to determine the immune cells involved in the anti-tumour response as well as a variety of pharmacokinetic parameters including the maximum tolerated dose, optimal dosing regimen and potential immunogenicity. However, because the fusion protein is composed of IL-2, it is likely that it will function in many, although perhaps not all, respects like free IL-2, and activate NK and T cells. It remains to be determined how the fusion protein compares with free IL-2 in terms of efficacy.

IL-21 has been implicated in the pathogenesis of type 1 diabetes on the basis of the knowledge of the immune pathophysiology of a non-obese diabetic (NOD) mouse

strain [13, 14]. IL-21 stimulates the proliferation of both T and B cells and terminal differentiation of natural killer (NK) cells, enhances the cytotoxic activity of CD8+ T cells [15-17], counteracts the suppressive effects of regulatory T cells [18] and stimulates non-immune cells to generate inflammatory mediators [19]. Recently, the importance of IL-21 [20] and its related T helper type 17 (Th17) cells [21, 22] has emerged in the pathogenesis of type 1 diabetes as well in other autoimmune diseases [23, 24] in humans. The Th-cell-subset-specific GDC-0199 ic50 expression of the IL-21 proximal promoter is controlled via the action of several transcription factors, including

nuclear factor-activated T cells, cytoplasmic 2 (NFATc2), T-bet and leucine-zipper transcription factor Maf (c-MAF) [25, 26]. Due to the pleiotropic effects of IL-21 on immune regulation, it is important to elucidate the genetically driven changes in its function and regulation that Ganetespib might affect the autoimmune process and cause beta cell destruction. The presence of autoantibodies against islet-cell antigens is the first indication of diabetes development and is a well-established fact. Currently, four autoantibodies are used to predict the development of T1AD: antibodies against glutamic acid decarboxylase (GAD65), tyrosine phosphatase-like protein (ICA512, also termed IA-2), insulin and the recently discovered zinc T8 transporter (ZnT8) [1, 2, 27]. T1AD is also associated frequently with other immune-mediated disorders [27, 28] such as autoimmune thyroiditis [29, 30], Addison’s disease [31], pernicious anaemia [32, 33] and coeliac disease [30, 34]. During the past few years, extensive research has been conducted to predict the occurrences of autoimmune diseases through the detection of organ-specific antibodies in T1D patients [27, 35]. Early detection of antibodies and latent organ-specific

dysfunction is important to alert physicians to take appropriate Niclosamide measures to prevent the progression to full-blown disease. Several autoimmune diseases are related to T1AD and elevated IL-21 expression in both human and animal models, as well as to a high frequency of the PTPN22 C1858T polymorphism. The Brazilian population is one of the most heterogeneous in the world, composed mainly of European (Caucasian descent, 0·771), African (0·143) and Amerindian (Native South American, 0·085) ancestry [36]. We hypothesized that the variants of these genes that regulate immune function would influence not only diabetes risk, but also the expression of other tissue-specific autoantibodies among patients with T1D in a Brazilian population.

3A and B). Various polarization conditions also influenced the chromatin conformation at the TNF TSS. Mouse CD4+ cells polarized under Th1 and Th17 conditions demonstrated a significant chromatin opening at the TNF TSS, while Th2 polarization resulted in a more closed chromatin configuration (Fig. 3C). Th0 cells cultured Selleckchem LY2157299 with immobilized anti-CD3 antibodies (Th0i) had somewhat more open conformation at TNF TSS than Th0 cells cultured with soluble anti-CD3 antibodies (Th0s) (Fig. 3C). Polarized Th1 and Th17 cell subsets also demonstrated elevated levels of activating histone H3 lysine 4 3-methylation (H3K4me3) (Fig. 3D and Supporting Information Fig. 4A). In contrast to polarized T cells, we did not

find any difference in the level of H3K4me3 modification between quiescent and activated T cells (Supporting Information

Fig. 4B). To find out if any of buy PD-0332991 the major TCR-activated transcription factors were involved in chromatin remodeling at TNF TSS, pull-down assay from the total lysate of EL4 T cells stimulated for 3 h with PMA and ionomycin was applied utilizing DNA probes spanning several regulatory elements of the TNF gene, including proximal promoter/TSS, enhancer in TNF intron 3, and enhancer downstream of TNF gene (3′TNF enhancer). Biotinylated amplicon from LT-α exon 4 was used as negative control. We evaluated binding of c-Jun, JunB, c-Fos, and ATF-2 members of AP-1 family; NFATc2 (NFAT1) and NFATc1 (NFAT2) members of NFAT family; and RelA/p65 and c-Rel members of NF-κB family of transcription factors (Fig. 4A). As a result, selective binding of NFATc2 and c-Jun to the amplicon covering the proximal promoter/TSS of the mouse TNF gene was observed in accordance with previous reports [24-29, 49-51]. Such interactions at TNF proximal promoter/TSS appeared to be evolutionary conserved and were observed also in human T cells [28, 52]. Some c-Rel binding to the proximal promoter/TSS of TNF

was also detected (Fig. 4A). Surprisingly, in contrast to previous reports, we observed relatively weak binding of ATF-2 to the mouse TNF proximal promoter (Fig. 4A) [28, 29, 50, 51]. To confirm interaction of NFATc2 and c-Jun with proximal promoter/TSS of TNF, we performed chromatin immunoprecipitation assay (Fig. 4B and C). Increased binding GABA Receptor of these transcription factors (including pS73 form of c-Jun) at TNF proximal promoter (−174 −55) and TSS (−50 +73) was observed after stimulation of naive T cells with anti-CD3/anti-CD28 (Fig. 4B). We also observed stronger binding of c-Jun to the proximal promoter/TSS of TNF in quiescent Th1 and Th17 in comparison to Th0 and Th2 cells (Fig. 4C). Unpolarized cells, cultured with immobilized anti-CD3 antibodies (Th0i), showed intermediate level of binding of c-Jun with TNF proximal promoter/TSS (Fig. 4C), correlating with more open (in comparison with Th0s cells) TNF TSS conformation (Fig. 3C).

Furthermore, BbGL-IIc induced iNKT cell activation occurs independently of MyD88 and TRIF signaling (49). These results show that BbGL-IIc is a bacterial antigen for the mouse iNKT cell TCR. BbGL-II compounds also stimulate human iNKT cells to release cytokines. Interestingly, BbGL-IIf, which contains linoleic acid (C18:2) in the sn-1 position and oleic acid in the sn-2 position, has been found to PD 332991 be the most potent

antigen for human iNKT cells (49). Data from another study suggest that the different iNKT cell responses to Borrelia glycolipids are due to a difference between human and mouse CD1d molecules (51). These studies show that iNKT cell TCR detects DAGs, another category of glycolipid, in addition to glycosphingolipids.

Moreover, DAG antigen induced iNKT cell activation is dependent on acyl chain length and saturation (49). The TCR of iNKT cells recognizes Sphingomonas GSL and B. burgdorferi DAG as well as αGalCer. Although the structures of these bacterial antigens are similar to that of αGalCer (Fig. check details 5), there are several small structural differences. DAG belongs to a different category of glycolipid than do αGalCer and Sphingomonas GSL. Also, the bacterial antigens are less potent than αGalCer. What determines the antigenic potency of these glycolipids? To address this point, crystal structures of mouse CD1d in complex with Sphingomonas GalAGSL or B. burgdorferi DAG were determined (51, 52). GalAGSL binds to mouse CD1d similarly to αGalCer. Between the α1 and α2 helices, the CD1d molecule has two pockets (A′ and F′) which accommodate Phospholipase D1 the lipid tails of antigens (Fig. 6a, b) (6, 7). The fatty acid and sphinganine tails of GalAGSL extend into the A′ and F′ pockets, respectively (52). However, because of an alternative hydrogen-bonding interaction, the sphinganine tail of GalAGSL, which lacks 4-OH, is more deeply inserted into the F′ pocket (52). The sugar head group of GalAGSL is present in the center of the binding groove at

the CD1d surface where an incoming TCR recognizes antigens (Fig. 6b, c), but it shows a slight lateral shift compared to αGalCer (52). These differences are thought to cause the difference in antigenic potency between Sphingomonas GalAGSL and αGalCer. The binding of B. burgdorferi galactosyl DAG is more flexible than that of Sphingomonas GalAGSL or αGalCer. The sn-1 linked oleic acid and the sn-2 linked palmitic acid of BbGL-IIc are inserted into the A′ and F′ pockets, respectively (51). The glycerol moiety of BbGL-IIc is tilted toward the α1 helix of the CD1d molecule, and the galactose of BbGL-IIc is pointed upward and away from the α2 helix of CD1d. These differences result in the loss of important hydrogen bonding interactions with the amino acids in the α2 helix that are present in the case of αGalCer (51).