Defining HLA-II Ligand Processing and Binding Rules with Mass Spectrometry Enhances Cancer Epitope Prediction.

Increasing evidence indicates CD4+ T cells can recognize cancer-specific antigens and control tumor growth. However, it remains difficult to predict the antigens that will be presented by human leukocyte antigen class II molecules (HLA-II), hindering efforts to optimally target them therapeutically. Obstacles include inaccurate peptide-binding prediction and unsolved complexities of the HLA-II pathway. To address these challenges, we developed an improved technology for discovering HLA-II binding motifs and conducted a comprehensive analysis of tumor ligandomes to learn processing rules relevant in the tumor microenvironment. We profiled >40 HLA-II alleles and showed that binding motifs were highly sensitive to HLA-DM, a peptide-loading chaperone. We also revealed that intratumoral HLA-II presentation was dominated by professional antigen-presenting cells (APCs) rather than cancer cells. Integrating these observations, we developed algorithms that accurately predicted APC ligandomes, including peptides from phagocytosed cancer cells. These tools and biological insights will enable improved HLA-II-directed cancer therapies.

Species-specific CD4+ T cells enable prediction of mucosal immune phenotypes from microbiota composition.

How bacterial strains within a complex human microbiota collectively shape intestinal T cell homeostasis is not well understood. Methods that quickly identify effector strains or species that drive specific mucosal T cell phenotypes are needed to define general principles for how the microbiota modulates host immunity. We colonize germ-free mice with defined communities of cultured strains and profile antigen-specific responses directed toward individual strains ex vivo. We find that lamina propria T cells are specific to bacterial strains at the species level and can discriminate between strains of the same species. Ex vivo restimulations consistently identify the strains within complex communities that induce Th17 responses in vivo, providing the potential to shape baseline immune tone via community composition. Using an adoptive transfer model of colitis, we find that lamina propria T cells respond to different bacterial strains in conditions of inflammation versus homeostasis. Collectively, our approach represents a unique method for efficiently predicting the relative impact of individual bacterial strains within a complex community and for parsing microbiota-dependent phenotypes into component fractions.

Survivin: a unique target for tumor therapy.

Survivin is the smallest member of the Inhibitor of apoptosis (IAP) family of proteins, involved in inhibition of apoptosis and regulation of cell cycle. These functional attributes make Survivin a unique protein exhibiting divergent functions i.e. regulating cell proliferation and cell death. Expression pattern of Survivin is also distinctive; it is prominently expressed during embryonal development, absent in most normal, terminally differentiated tissues but upregulated in a variety of human cancers. Expression of Survivin in tumours correlates with not only inhibition of apoptosis and a decreased rate of cell death, but also resistance to chemotherapy and aggressiveness of tumours. Therefore, Survivin is an important target for cancer vaccines and therapeutics. Survivin has also been found to be prominently expressed on both human and embryonic stem cells and many somatic stem cell types indicating its yet unexplored role in stem cell generation and maintenance. Overall, Survivin emerges as a molecule with much wider role in cellular homeostasis. This review will discuss various aspects of Survivin biology and its role in regulation of apoptosis, cell division, chemo-resistance and tumour progression. Various molecular and immunotherapeutic approaches targeting Survivin will also be discussed.

Evaluation of marginal bone loss around dental implants in cigarette smokers and nonsmokers. A comparative study.

BACKGROUND: The overall success of osteointegrated dental implants depends on various factors. The deleterious effects of smoking on wound healing after the tooth extraction and its association with poor quality of bone are well documented. Similar effects of tobacco use on the success of dental implants are expected. Cigarette smoke mainly contains nicotine that delays the bone healing and increases the rate of infections at the implant insertion site. AIM: The purpose of the present study was to evaluate and compare the marginal bone loss around dental implants in smokers and nonsmokers. MATERIALS AND METHODS: The study was conducted on 500 individuals who received dental implants in maxillary or mandibular edentulous regions from 2010 to 2017. The sample was divided into two groups: Group I (smokers, n = 280) and Group II (nonsmokers, n = 220). Marginal bone loss was measured on mesial, distal, buccal, and lingual side of each implant using periapical radiographs 3 months after loading, 6 months after loading, and 12 months after loading. RESULTS: The crestal bone loss around dental implants was significantly greater in smokers (Group I) as compared to nonsmokers (Group II) irrespective of the duration of loading (P < 0.001). Marginal bone loss did vary significantly by location in either groups. CONCLUSION: Smoking overall lowers the success rate of dental implants. Increased duration and frequency of smoking leads to a greater degree of marginal bone loss around dental implants.

Comparative evaluation of role of hs C -reactive protein as a diagnostic marker in chronic periodontitis patients.

BACKGROUND AND AIM: C-reactive protein (CRP) is a type I acute phase protein, which can increase up to 1000 fold after the onset of a stimulus. It is a phylogenetically highly conserved plasma protein with homolog in vertebrates and many invertebrates that participate in systemic response to inflammation. Serum C-reactive protein levels are raised in patients with myocardial infarction and periodontitis, providing a potential mechanism to link destructive periodontal disease with an increased risk for other atherosclerotic complications. The purpose of the present study was to estimate and compare the levels of hs- C Reactive protein in chronic periodontitis patients before and after non-surgical periodontal therapy. METHODS: The study sample consisted of 45 individuals of age group 30-60 years that was divided into two groups Group I (control) and Group II (patients with chronic generalized periodontitis). The clinical parameters such as plaque index, calculus index, gingival index, probing pocket depth, clinical attachment level, and serum hs-CRP levels were recorded for these individuals. RESULTS: The patients with healthy gingiva possessed a mean hs-CRP level of 0.252 ± 0.0393 which was lower as compared to the patients with chronic periodontitis. In periodontitis patients mean levels of hs-CRP was 0.106 ± 0.029 which reduced to 0.044 ± 0.027 after periodontal therapy. A significantly elevated CRP level was found in subjects with periodontitis compared to the controls. CONCLUSION: The serum levels of C-reactive protein were elevated in patients with periodontitis and this might be a diagnostic marker for cardiovascular diseases.

Update on psoriasis: A review.

Psoriasis is a disease characterized by the presence of papules and plaques over the surface of skin with variable morphology, distribution and severity. The lesions of psoriasis are distinct from these other entities and are classically very well circumscribed, circular, red papules or plaques with a grey or silvery-white, dry scale. In addition, the lesions are typically distributed symmetrically on the scalp, elbows, knees, lumbosacral area, and in the body folds. The oral manifestations of psoriasis may involve the oral mucosa or the tongue. The dorsal surface of the tongue shows characteristic red patches surrounded with a yellow white border. The relationship between eye lesions and psoriasis are the current findings in the literature. The ocular complications along with the several extracutaneous manifestations are common complications seen in psoriasis. The pathogenesis of exact relationship between these two is still controversial. Immunological studies have shown a positive relationship between T helper cells and uveitis. Various signs and symptoms of ocular psoriasis may be overlooked. Thus, a complete understanding of ophthalmic involvement is important to the comprehensive care of patients with psoriasis. Almost any part of the body can be affected in psoriasis, but the ophthalmic complications of psoriasis usually remain clinically subtle. This review highlights the various manifestations of psoriasis with their clinical sign and symptoms.

Effect of heat sterilization and chemical method of sterilization on the polyvinyl siloxane impression material. A comparative study.

BACKGROUND: Dental impression is a crucial part of the process of constructing a well-fitting prosthesis. In the clinical scenario, impressions can act as a vehicle for the transfer of bacteria and fungi. Therefore, an attempt was made to evaluate the dimensional accuracy of the newly introduced polyvinyl siloxane (PVS) impression material upon autoclaving and comparing it to the traditional means of chemical disinfection. MATERIALS AND METHODS: A cross-sectional comparative in vitro study was conducted. Three groups were made for testing different sterilization methods. The sample size for the study was kept as 30 observations in each of the three groups. Test samples were prepared by making an impression of the die using the putty-wash technique. Statistical analysis was done by applying unpaired t-test, paired t-test, one-way analysis of variance (ANOVA) and post hoc Tukey's honestly significant difference (HSD). RESULTS: Initial mean of samples of group I were compared to A (actual measurement of metal ruled block = 24.960), a dimensional change of 1.6% was found. Similarly, in group II, a change of 1.59% was found and in group III the change was 1.7%. There was mean shrinkage of 24.557 mm in group I, 24.586 mm in group II, and 24.535 mm in group III and these changes were found statistically significant. CONCLUSION: Dimensional changes in the impression material after disinfection with 2% glutaraldehyde were considered high compared to autoclaving and, hence, it may not be advisable to disinfect this material with 2% glutaraldehyde.

Compartmental Analysis of T-cell Clonal Dynamics as a Function of Pathologic Response to Neoadjuvant PD-1 Blockade in Resectable Non-Small Cell Lung Cancer.

PURPOSE: Neoadjuvant PD-1 blockade is a promising treatment for resectable non-small cell lung cancer (NSCLC), yet immunologic mechanisms contributing to tumor regression and biomarkers of response are unknown. Using paired tumor/blood samples from a phase II clinical trial (NCT02259621), we explored whether the peripheral T-cell clonotypic dynamics can serve as a biomarker for response to neoadjuvant PD-1 blockade. EXPERIMENTAL DESIGN: T-cell receptor (TCR) sequencing was performed on serial peripheral blood, tumor, and normal lung samples from resectable NSCLC patients treated with neoadjuvant PD-1 blockade. We explored the temporal dynamics of the T-cell repertoire in the peripheral and tumoral compartments in response to neoadjuvant PD-1 blockade by using the TCR as a molecular barcode. RESULTS: Higher intratumoral TCR clonality was associated with reduced percent residual tumor at the time of surgery, and the TCR repertoire of tumors with major pathologic response (MPR; <10% residual tumor after neoadjuvant therapy) had a higher clonality and greater sharing of tumor-infiltrating clonotypes with the peripheral blood relative to tumors without MPR. Additionally, the posttreatment tumor bed of patients with MPR was enriched with T-cell clones that had peripherally expanded between weeks 2 and 4 after anti-PD-1 initiation and the intratumoral space occupied by these clonotypes was inversely correlated with percent residual tumor. CONCLUSIONS: Our study suggests that exchange of T-cell clones between tumor and blood represents a key correlate of pathologic response to neoadjuvant immunotherapy and shows that the periphery may be a previously underappreciated originating compartment for effective antitumor immunity.See related commentary by Henick, p. 1205.

Persistent mutant oncogene specific T cells in two patients benefitting from anti-PD-1.

BACKGROUND: Several predictive biomarkers are currently approved or are under investigation for the selection of patients for checkpoint blockade. Tumor PD-L1 expression is used for stratification of non-small cell lung (NSCLC) patients, with tumor mutational burden (TMB) also being explored with promising results, and mismatch-repair deficiency is approved for tumor site-agnostic disease. While tumors with high PD-L1 expression, high TMB, or mismatch repair deficiency respond well to checkpoint blockade, tumors with lower PD-L1 expression, lower mutational burdens, or mismatch repair proficiency respond much less frequently. CASE PRESENTATION: We studied two patients with unexpected responses to checkpoint blockade monotherapy: a patient with PD-L1-negative and low mutational burden NSCLC and one with mismatch repair proficient colorectal cancer (CRC), both of whom lack the biomarkers associated with response to checkpoint blockade, yet achieved durable clinical benefit. Both maintained T-cell responses in peripheral blood to oncogenic driver mutations - BRAF-N581I in the NSCLC and AKT1-E17K in the CRC - years after treatment initiation. Mutation-specific T cells were also found in the primary tumor and underwent dynamic perturbations in the periphery upon treatment. CONCLUSIONS: These findings suggest that T cell responses to oncogenic driver mutations may be more prevalent than previously appreciated and could be harnessed in immunotherapeutic treatment, particularly for patients who lack the traditional biomarkers associated with response. Comprehensive studies are warranted to further delineate additional predictive biomarkers and populations of patients who may benefit from checkpoint blockade.

Correction to: persistent mutant oncogene specific T cells in two patients benefitting from anti-PD-1.

.

Hedgehog signaling and Bmi-1 regulate self-renewal of normal and malignant human mammary stem cells.

The epithelial components of the mammary gland are thought to arise from stem cells with a capacity for self-renewal and multilineage differentiation. Furthermore, these cells and/or their immediate progeny may be targets for transformation. We have used both in vitro cultivation and a xenograft mouse model to examine the role of hedgehog signaling and Bmi-1 in regulating self-renewal of normal and malignant human mammary stem cells. We show that hedgehog signaling components PTCH1, Gli1, and Gli2 are highly expressed in normal human mammary stem/progenitor cells cultured as mammospheres and that these genes are down-regulated when cells are induced to differentiate. Activation of hedgehog signaling increases mammosphere-initiating cell number and mammosphere size, whereas inhibition of the pathway results in a reduction of these effects. These effects are mediated by the polycomb gene Bmi-1. Overexpression of Gli2 in mammosphere-initiating cells results in the production of ductal hyperplasia, and modulation of Bmi-1 expression in mammosphere-initiating cells alters mammary development in a humanized nonobese diabetic-severe combined immunodeficient mouse model. Furthermore, we show that the hedgehog signaling pathway is activated in human breast "cancer stem cells" characterized as CD44+CD24-/lowLin-. These studies support a cancer stem cell model in which the hedgehog pathway and Bmi-1 play important roles in regulating self-renewal of normal and tumorigenic human mammary stem cells.

The Mutation-Associated Neoantigen Functional Expansion of Specific T Cells (MANAFEST) Assay: A Sensitive Platform for Monitoring Antitumor Immunity.

Mutation-associated neoantigens (MANA) are a target of antitumor T-cell immunity. Sensitive, simple, and standardized assays are needed to assess the repertoire of functional MANA-specific T cells in oncology. Assays analyzing in vitro cytokine production such as ELISpot and intracellular cytokine staining have been useful but have limited sensitivity in assessing tumor-specific T-cell responses and do not analyze antigen-specific T-cell repertoires. The FEST (Functional Expansion of Specific T cells) assay described herein integrates T-cell receptor sequencing of short-term, peptide-stimulated cultures with a bioinformatic platform to identify antigen-specific clonotypic amplifications. This assay can be adapted for all types of antigens, including MANAs via tumor exome-guided prediction of MANAs. Following in vitro identification by the MANAFEST assay, the MANA-specific CDR3 sequence can be used as a molecular barcode to detect and monitor the dynamics of these clonotypes in blood, tumor, and normal tissue of patients receiving immunotherapy. MANAFEST is compatible with high-throughput routine clinical and lab practices. Cancer Immunol Res; 6(8); 888-99. ©2018 AACR.

Improvement of human keratinocyte migration by a redox active bioelectric dressing.

Exogenous application of an electric field can direct cell migration and improve wound healing; however clinical application of the therapy remains elusive due to lack of a suitable device and hence, limitations in understanding the molecular mechanisms. Here we report on a novel FDA approved redox-active Ag/Zn bioelectric dressing (BED) which generates electric fields. To develop a mechanistic understanding of how the BED may potentially influence wound re-epithelialization, we direct emphasis on understanding the influence of BED on human keratinocyte cell migration. Mapping of the electrical field generated by BED led to the observation that BED increases keratinocyte migration by three mechanisms: (i) generating hydrogen peroxide, known to be a potent driver of redox signaling, (ii) phosphorylation of redox-sensitive IGF1R directly implicated in cell migration, and (iii) reduction of protein thiols and increase in integrinαv expression, both of which are known to be drivers of cell migration. BED also increased keratinocyte mitochondrial membrane potential consistent with its ability to fuel an energy demanding migration process. Electric fields generated by a Ag/Zn BED can cross-talk with keratinocytes via redox-dependent processes improving keratinocyte migration, a critical event in wound re-epithelialization.