Cytotoxic T lymphocytes (CTL) recognize short antigenic peptides in association with class I MHC molecules at the cell surface. Newly synthesized viral polypeptides are processed in the cytoplasm and ...the fragments of antigen are transported into the endoplasmic reticulum (ER) via a peptide transporter where they complex with nascent class I molecules. The peptide-MHC complex is transported to the cell surface and presented to CTL. Sequence analysis of endogenously expressed, MHC-associated self or viral antigens indicates that the naturally processed peptides bound to class I MHC molecules are in general 9 +/- 1 residues long. Peptides bound to specific class I MHC molecules have in common allele-specific motifs of conserved residues. The motif for the class I Kd molecules has been shown to be nine or 10 residues with the sequence X-Tyr-(X)6-I/L or X-Tyr-(X)7-I/L. The Tyr residue at the second position and the I/L residue at the ninth position are allele-specific anchor residues which appear to be required for binding of the peptide to Kd. To examine the stringency of the requirement for Tyr at the second position, we have performed saturation mutagenesis of a minigene encoding the class I Kd-restricted influenza HA210-219 site at the Tyr residue 211. A series of 10 mutants was tested for effects on target-cell sensitization. Most amino acid substitutions for the Tyr residue resulted in a loss of endogenous peptide recognition by HA210-219 reactive CTL, consistent with the critical role of the Tyr at the second position for interaction with Kd molecules. One mutant gene-product encoding a His substitution for the Tyr residue was recognized by CTL. However, the corresponding synthetic peptide containing a His substitution at the dominant anchor position bound only weakly to Kd, and target cells treated with the peptide were poorly recognized by CTL. The endogenous His-containing peptide was also less stably associated with class I MHC Kd molecules at the cell surface than the wild-type Tyr peptide. These data indicate that endogenous antigenic peptides may bind newly-synthesized class I MHC molecules in the ER more efficiently than fully formed class I molecules at the cell surface and that endogenous peptides may dissociate from class I MHC molecules at different rates. The implication of these findings for CTL recognition and epitope mapping are discussed.
The parasite Entamoeba histolytica is named for its ability to lyse host tissues. To determine the factors responsible, we have initiated an examination of the contribution of parasite virulence ...factors and host caspases to cellular destruction by the parasite. Amoebic colitis in C3H/HeJ mice was associated with extensive host apoptosis at sites of E. histolytica invasion. In vitro studies of E. histolytica–Jurkat T‐cell interactions demonstrated that apoptosis required contact via the amoebic Gal/GalNAc lectin, but was unaffected by 75% inhibition of the amoebic cysteine proteinases. Parasite‐induced DNA fragmentation was unaffected in caspase 8‐deficient Jurkat cells treated with the caspase 9 inhibitor Ac‐LEHD‐fmk. In contrast, caspase 3‐like activity was observed within minutes of E. histolytica contact and the caspase 3 inhibitor Ac‐DEVD‐CHO blocked Jurkat T cell death, as measured by both DNA fragmentation and 51Cr release. These data demonstrate rapid parasite‐induced activation of caspase 3‐like caspases, independent of the upstream caspases 8 and 9, which is required for host cell death.
Full text
Available for:
BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
The nuclear run-on assay is the most commonly used technique to determine transcription rates of specific genes such as tyrosine hydroxylase. Its application to studies in the nervous system is ...problematic, however, as a result of limitations in sensitivity and the loss of anatomical integrity. We observed that the relative levels of tyrosine hydroxylase intron 2-containing RNA using a ribonuclease protection assay in the adrenal medulla changed in response to pharmacological treatments consistently with changes shown by the nuclear run-on assay. Our results indicate that measures of tyrosine hydroxylase primary transcript levels offer an alternative to the nuclear run-on assay and validate the application of intron-specific in situ hybridization as a means of assessing the relative transcriptional activity of the tyrosine hydroxylase gene. Similar quantitative results were obtained using intron-specific in situ hybridization with oligonucleotide probes specific for rat tyrosine hydroxylase intron 2. Furthermore, we observed that intron-specific in situ hybridization could be used to measure tyrosine hydroxylase transcription rates in the locus coeruleus, providing resolution at the level of single neurons. Thus, measuring the levels of tyrosine hydroxylase intron 2 provides a sensitive measure of tyrosine hydroxylase transcription rate that can be applied to the study of brain catecholaminergic neurons.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Abstract only
TPS493
Background: Immune checkpoint inhibitors, including nivo (anti–PD-1), have demonstrated favorable tolerability and efficacy profiles, ushering in a new treatment (tx) paradigm ...for advanced bladder cancer (advBC). However, an unmet need exists for new effective tx options in earlier stages of disease, specifically for patients (pts) with BCG-unresponsive, high-risk NMIBC. Increased IDO and PD-L1 expression in NMIBC tumors (Inman, et al. Cancer 2007; Hudolin, et al. Anticancer Res 2017), support the combination of anti–PD-1 and IDO1 inhibition in NMIBC. BMS-986205, a selective, potent, once-daily IDO1 inhibitor that works early in the IDO1 pathway, has demonstrated clinical activity in combination with nivo in pts with immunotherapy-naive advBC who received ≥ 1 prior line of therapy (objective response rate, 37%; Tabernero, et al. J Clin Oncol 2018;36(suppl) abstr 4512). These findings provide a rationale for investigation of nivo + BMS-986205 ± intravesical BCG therapy in BCG-unresponsive high-risk NMIBC. Here we describe a phase 2, randomized, open-label study assessing the safety and efficacy of nivo ± BMS-986205 ± intravesical BCG in pts with BCG-unresponsive, high-risk NMIBC. Methods: Pts aged ≥ 18 years with BCG-unresponsive (per February 2018 FDA guidance), high-risk NMIBC, defined as carcinoma-in-situ (CIS) with or without papillary component, any T1, or Ta high-grade lesions, will be enrolled. Pts must have urothelial carcinoma as the predominant histological component (>50%). Key exclusion criteria include locally advanced or metastatic BC, upper urinary tract disease within 2 years, prostatic urethral disease within 1 year, and prior immunotherapy. Using a novel adaptive-type design, pts will be randomized to 1 of 4 tx arms with nivo ± BMS-986205 ± BCG. Primary endpoints include proportion of pts with CIS with complete response (CR), duration of CR in pts with CIS, and event-free survival for all pts without CIS. Secondary endpoints are progression-free survival and safety. This global study in 13 countries is underway, with a target enrollment of 436 pts. ( Clinical trial information: NCT03519256.
We present a search for high-mass neutral resonances using dimuon data corresponding to an integrated luminosity of 2.3 fb(-1) collected in ppover collisions at sqrts=1.96 TeV by the CDF II detector ...at the Fermilab Tevatron. No significant excess above the standard model expectation is observed in the dimuon invariant-mass spectrum. We set 95% confidence level upper limits on sigmaBR(pp-->X-->micromicro), where X is a boson with spin-0, 1, or 2. Using these cross section limits, we determine lower mass limits on sneutrinos in R-parity-violating supersymmetric models, Z' bosons, and Kaluza-Klein gravitons in the Randall-Sundrum model.
Full text
Available for:
CMK, CTK, FMFMET, IJS, NUK, PNG, UM
Synchrotron X-ray bioimaging was successfully carried out to observe bone regeneration by a novel artificial bone substitute of bioactive MegaGen Synthetic Bone (MGSB) and hyaluronate (HA) hydrogels. ...A biphasic calcium phosphate of MGSB was prepared by chemical precipitation method, with a porous spherical morphology. On the basis of the fact that HA plays important roles in bone regeneration and promotes the differentiation, vascularization, and migration of stem cells, HA-cystamine (CYS) hydrogels with cleavable disulfide linkages were prepared to supply HA continuously for effective bone regeneration by their controlled degradation in vivo. Among seven different samples using Bio-OSS®, MGSB, and/or several kinds of HA hydrogels, MGSB/HA-CYS hydrogels resulted in the most significant bone regeneration in the calvarial critical bone defect of New Zealand white rabbits. Histological and histomorphometric analyses revealed that the bone regeneration by MGSB/HA-CYS hydrogels was as high as 43%, occupying 71% of the bone defect area with MGSB in the form of a calvarial bone plate in 4 weeks. After that, MGSB was bioabsorbed and replaced gradually with regenerated bones as observed in 8 weeks. Synchrotron X-ray imaging clearly confirmed the effective bone regeneration by MGSB/HA-CYS hydrogels, showing three-dimensional micron-scale morphologies of regenerated bones interconnected with MGSB. In addition, sequential nondestructive synchrotron X-ray tomographic analysis results from anterior to posterior of the samples were well matched with the histomorphometric analysis results. The clinically feasible artificial bone substitutes of MGSB/HA-CYS hydrogels will be investigated further for various bone tissue engineering applications using the synchrotron X-ray bioimaging systems.
We present the first observation of exclusive e(+)e(-) production in hadron-hadron collisions, using ppover collision data at (square root) s = 1.96 TeV taken by the run II Collider Detector at ...Fermilab, and corresponding to an integrated luminosity of 532 pb(-1). We require the absence of any particle signatures in the detector except for an electron and a positron candidate, each with transverse energy E(T) > 5 GeV and pseudorapidity |eta| < 2. With these criteria, 16 events are observed compared to a background expectation of 1.9+/-0.3 events. These events are consistent in cross section and properties with the QED process ppover --> p + e(+)e(-) + pover through two-photon exchange. The measured cross section is 1.6(-0.3)(+0.5)(stat) +/- 0.3(syst) pb. This agrees with the theoretical prediction of 1.71+/-0.01 pb.
Full text
Available for:
CMK, CTK, FMFMET, IJS, NUK, PNG, UM
PDF
