Host Immune Activity Research Articles

Depletion of regulatory T cells enhancing the anti-tumor effect of in situ vaccination in solid tumors

The emergence of immune checkpoint inhibitors (ICIs) has revolutionized the clinical treatment for tumor. However, the low response rate of ICIs remains the major obstacle for curing patients and effective approaches for patients with primary or secondary resistance to ICIs remain lacking. In this study, immune stimulating agent unmethylated CG-enriched (CpG) oligodeoxynucleotide (ODN) was locally injected into the tumor to trigger a robust immune response to eradicate cancer cells, while anti-CD25 antibody was applied to remove immunosuppressive regulatory T cells, which further enhanced the host immune activity to attack tumor systematically. The combination of CpG and anti-CD25 antibody obtained notable regression in mouse melanoma model. Furthermore, rechallenge of tumor cells in the xenograft model has resulted in smaller tumor volume, which demonstrated that the combinational treatment enhanced the activity of memory T cells. Remarkably, this combinational therapy presented significant efficacy on multiple types of tumors as well and was able to prevent relapse of tumor partially. Taken together, our combinational immunotherapy provides a new avenue to enhance the clinical outcomes of patients who are insensitive or resistant to ICIs treatments.

Selection of epigenetically privileged HIV-1 proviruses during treatment with panobinostat and interferon-α2a

CD4+ Tcells with latent HIV-1 infection persist despite treatment with antiretroviral agents and represent the main barrier to a cure of HIV-1 infection. Pharmacological disruption of viral latency may expose HIV-1-infected cells to host immune activity, but the clinical efficacy of latency-reversing agents for reducing HIV-1 persistence remains to be proven. Here, we show in a randomized-controlled human clinical trial that the histone deacetylase inhibitor panobinostat, when administered in combination with pegylated interferon-α2a, induces a structural transformation of the HIV-1 reservoir cell pool, characterized by a disproportionate overrepresentation of HIV-1 proviruses integrated in ZNF genes and in chromatin regions with reduced H3K27ac marks, the molecular target sites for panobinostat. By contrast, proviruses near H3K27ac marks wereactively selected against, likely due to increased susceptibility to panobinostat. These data suggest that latency-reversing treatment can increase the immunological vulnerability of HIV-1 reservoir cells and accelerate the selection of epigenetically privileged HIV-1 proviruses.

Diet and the gut microbiota-immune axis in the context of perinatal mental health: Protocol for a prospective cohort study.

Physiological and psychosocial changes experienced by women during the perinatal period may put them at risk for postpartum mental health disturbances. Accumulating evidence suggests that dietary patterns may influence mental health through the modulation of the gut microbiota and its effects on host immune activity. Thus, targeting the gut microbiota via dietary intake could serve as both a preventative and therapeutic strategy in improving perinatal mental health. Here, we present a protocol for a prospective cohort study that primarily aims to determine if diet quality during pregnancy is protective against postpartum depression severity. Secondary objectives will examine if microbiota- and blood-based inflammatory markers may be associated with the relationship between prenatal diet quality and postpartum depression severity, as well as with associations between additional dietary and mental health outcomes. Dietary patterns and mental health symptoms will be documented in 100 pregnant women at 4 time points during pregnancy and postpartum. Participants will also provide stool and blood samples at the same time points to determine microbiota composition and predicted function and inflammatory factors, respectively. Stool microbiota will be analyzed using 16S ribosomal RNA gene sequencing and bioinformatics tools (QIIME 2/PICRUSt2). Inflammatory factors will be determined using high-sensitivity antibody-based immunoassays. Statistical analyses will include linear mixed models and hierarchical linear mixed effect models. The study was approved by the Research Ethics Boards of the Royal Ottawa Health Care Group (#2022002) and of the University of Ottawa (#H-06-22-8013). Informed consent will be obtained from all participants before their enrollment. Findings from this study will help develop evidence-based dietary recommendations and potential interventions for women susceptible to or suffering from postpartum mental health issues that are accessible, noninvasive, and have potential to play a role in prevention and treatment.

Drosophila Gut Immune Pathway Suppresses Host Development-Promoting Effects of Acetic Acid Bacteria.

The physiology of most organisms, including Drosophila, is heavily influenced by their interactions with certain types of commensal bacteria. Acetobacter and Lactobacillus, two of the most representative Drosophila commensal bacteria, have stimulatory effects on host larval development and growth. However, how these effects are related to host immune activity remains largely unknown. Here, we show that the Drosophila development-promoting effects of commensal bacteria are suppressed by host immune activity. Mono-association of germ-free Drosophila larvae with Acetobacter pomorum stimulated larval development, which was accelerated when host immune deficiency (IMD) pathway genes were mutated. This phenomenon was not observed in the case of mono-association with Lactobacillus plantarum. Moreover, the mutation of Toll pathway, which constitutes the other branch of the Drosophila immune pathway, did not accelerate A. pomorum-stimulated larval development. The mechanism of action of the IMD pathway-dependent effects of A. pomorum did not appear to involve previously known host mechanisms and bacterial metabolites such as gut peptidase expression, acetic acid, and thiamine, but appeared to involve larval serum proteins. These findings may shed light on the interaction between the beneficial effects of commensal bacteria and host immune activity.

Kinetics and predictive value of HBcrAg, HBV RNA and anti-HBc during bulevirtide treatment of chronic HDV-infected patients.

The entry inhibitor bulevirtide (BLV) is a new treatment option for patients with chronic hepatitis D virus (HDV) infection and compensated liver disease. The aim of this study was to investigate the kinetic and predictive value of markers reflecting HBV cccDNA transcriptional activity and host immune response activity during BLV treatment in a real-life cohort of HDV infected patients. Levels of HDV RNA, HBV RNA, hepatitis B core related antigen (HBcrAg) and hepatitis B core antibodies (anti-HBc) were measured in 16 patients before (BL), after three (3M) and six (6M) months of treatment with BLV. All patients received nucleos(t)ide analogue treatment. HDV RNA declined in all patients during treatment. 38% (6/16) showed ≥ 2 log HDV RNA decline from BL to 6M and 11 patients (69%) normalized ALT levels. HBV RNA levels were low and only detectable in two to four patients. HBcrAg levels declined in 75% (12/16) of patients. Median HBcrAg levels declined significantly from BL to 6M (3.75 logU/ml (IQR 2.93-4.78) vs. 3.4 logU/ml (IQR 2-4.68), p=0.002). A similar trend was shown for anti-HBc between BL and 6M. Levels of HBcrAg or anti-HBc did not differ significantly between patients with or without ≥ 2 log HDV RNA decline from BL to 6M.After 6 months treatment with BLV, levels of HBcrAg showed a significant decline, while HBV RNA and anti-HBc levels did not change. Reduction of HBV cccDNA transcriptional activity and immunological effects of antiviral treatment might explain these changes.

The Function and Molecular Mechanism of Commensal Microbiome in Promoting Malignant Progression of Lung Cancer

The human commensal microbiome existing in an internal environment is relatively consistent with that of the host. The presence of bacterial dysbiosis, on the other hand, promptly results in the termination of this symbiotic association. The altered microbial structure in the lung may be responsible for the development of lung cancer by controlling the host's inflammatory response and influencing a variety of immunological pathways. More and more studies have pointed to the fact that the commensal microbiota plays a vital role in both the development of tumors and the body's response to lung cancer treatment. Microbiome dysbiosis, genotoxicity, virulence effect, and epigenetic dysregulations are some of the potential mechanisms that may lie behind the process of tumorigenesis that is mediated by microbiome. Other potential mechanisms include regulating host immune activity through a variety of pathogenic factors, dysregulating host metabolism as a result of microbiome alterations, and microbiome dysbiosis. In this historical overview, we go through some of the more recent mechanistic discoveries into the biological processes that are involved in lung cancer that are caused by bacteria. Without a question, obtaining a greater knowledge of the dynamic link between the lung microbiome and lung cancer has the potential to inspire the development of innovative early detection and customized treatment methods for lung cancer.

Increasing radiation doses in Anastrepha obliqua (Diptera: Tephritidae) larvae improve parasitoid mass-rearing attributes.

Doses of 40, 80, 120, and 160 Gy were applied to 5-, 6-, 7-, and 8-day-old Anastrepha obliqua larvae, which were exposed to the Neotropical-native braconids Doryctobracon crawfordi and Utetes anastrephae and the Asian braconid Diachasmimorpha longicaudata. These tests were performed to know the effect of the increase in host radiation on the emergence of the aforementioned parasitoids and the related consequences of oviposition on the host. The study was based on the fact that higher radiation doses may cause a decrease in the host immune activity. There was a direct relationship between the increase in radiation dose and the parasitoid emergence. Both, the weight and the mortality of the host larvae were not affected by radiation. Although the larval weight of the larvae was lower and the mortality was higher in the younger larvae. Both, the number of scars and immature stages per host puparium originated from the younger larvae were lower than those from older larvae. Only U. anastrephae superparasitized more at lower radiation. Superparasitism by D. longicaudata was more frequent at 160 Gy. Qualitative measurements of melanin in the larvae parasitized showed that the levels were lower with increasing radiation. As radiation doses increased, the antagonistic response of the A. obliqua larva was reduced. Host larvae aged 5- and 6-day-old irradiated at 120-160 Gy significantly improve parasitoid emergence. This evidence is relevant for the mass production of the three tested parasitoid species.

High-sensitivity pattern discovery in large, paired multiomic datasets.

MotivationModern biological screens yield enormous numbers of measurements, and identifying and interpreting statistically significant associations among features are essential. In experiments featuring multiple high-dimensional datasets collected from the same set of samples, it is useful to identify groups of associated features between the datasets in a way that provides high statistical power and false discovery rate (FDR) control.ResultsHere, we present a novel hierarchical framework, HAllA (Hierarchical All-against-All association testing), for structured association discovery between paired high-dimensional datasets. HAllA efficiently integrates hierarchical hypothesis testing with FDR correction to reveal significant linear and non-linear block-wise relationships among continuous and/or categorical data. We optimized and evaluated HAllA using heterogeneous synthetic datasets of known association structure, where HAllA outperformed all-against-all and other block-testing approaches across a range of common similarity measures. We then applied HAllA to a series of real-world multiomics datasets, revealing new associations between gene expression and host immune activity, the microbiome and host transcriptome, metabolomic profiling and human health phenotypes.Availability and implementationAn open-source implementation of HAllA is freely available at http://huttenhower.sph.harvard.edu/halla along with documentation, demo datasets and a user group.Supplementary information Supplementary data are available at Bioinformatics online.

Profiling gut microbiota and bile acid metabolism in critically ill children

Broad-spectrum antimicrobial use during the treatment of critical illness influences gastrointestinal fermentation endpoints, host immune response and metabolic activity including the conversion of primary to secondary bile acids. We previously observed reduced fermentation capacity in the faecal microbiota of critically ill children upon hospital admission. Here, we further explore the timecourse of the relationship between the microbiome and bile acid profile in faecal samples collected from critically ill children. The microbiome was assayed by sequencing of the 16S rRNA gene, and faecal water bile acids were measured by liquid chromatography mass spectrometry. In comparison to admission faecal samples, members of the Lachnospiraceae recovered during the late-acute phase (days 8–10) of hospitalisation. Patients with infections had a lower proportion of Lachnospiraceae in their gut microbiota than controls and patients with primary admitting diagnoses. Keystone species linked to ecological recovery were observed to decline with the length of PICU admission. These species were further suppressed in patients with systemic infection, respiratory failure, and undergoing surgery. Bile acid composition recovers quickly after intervention for critical illness which may be aided by the compositional shift in Lachnospiraceae. Our findings suggest gut microbiota recovery can be readily assessed via measurement of faecal bile acids.

RNA Sequencing in COVID-19 patients identifies neutrophil activation biomarkers as a promising diagnostic platform for infections.

Infection with the SARS-CoV2 virus can vary from asymptomatic, or flu-like with moderate disease, up to critically severe. Severe disease, termed COVID-19, involves acute respiratory deterioration that is frequently fatal. To understand the highly variable presentation, and identify biomarkers for disease severity, blood RNA from COVID-19 patient in an intensive care unit was analyzed by whole transcriptome RNA sequencing. Both SARS-CoV2 infection and the severity of COVID-19 syndrome were associated with up to 25-fold increased expression of neutrophil-related transcripts, such as neutrophil defensin 1 (DEFA1), and 3-5-fold reductions in T cell related transcripts such as the T cell receptor (TCR). The DEFA1 RNA level detected SARS-CoV2 viremia with 95.5% sensitivity, when viremia was measured by ddPCR of whole blood RNA. Purified CD15+ neutrophils from COVID-19 patients were increased in abundance and showed striking increases in nuclear DNA staining by DAPI. Concurrently, they showed >10-fold higher elastase activity than normal controls, and correcting for their increased abundance, still showed 5-fold higher elastase activity per cell. Despite higher CD15+ neutrophil elastase activity, elastase activity was extremely low in plasma from the same patients. Collectively, the data supports the model that increased neutrophil and decreased T cell activity is associated with increased COVID-19 severity, and suggests that blood DEFA1 RNA levels and neutrophil elastase activity, both involved in neutrophil extracellular traps (NETs), may be informative biomarkers of host immune activity after viral infection.

Circadian dynamics of the teleost skin immune-microbiome interface

BackgroundCircadian rhythms of host immune activity and their microbiomes are likely pivotal to health and disease resistance. The integration of chronotherapeutic approaches to disease mitigation in managed animals, however, is yet to be realised. In aquaculture, light manipulation is commonly used to enhance growth and control reproduction but may have unknown negative consequences for animal health. Infectious diseases are a major barrier to sustainable aquaculture and understanding the circadian dynamics of fish immunity and crosstalk with the microbiome is urgently needed.ResultsHere, using rainbow trout (Oncorhynchus mykiss) as a model, we combine 16S rRNA metabarcoding, metagenomic sequencing and direct mRNA quantification methods to simultaneously characterise the circadian dynamics of skin clock and immune gene expression, and daily changes of skin microbiota. We demonstrate daily rhythms in fish skin immune expression and microbiomes, which are modulated by photoperiod and parasitic lice infection. We identify putative associations of host clock and immune gene profiles with microbial composition. Our results suggest circadian perturbation, that shifts the magnitude and timing of immune and microbiota activity, is detrimental to fish health.ConclusionsThe substantial circadian dynamics and fish host expression-microbiome relationships we find represent a valuable foundation for investigating the utility of chronotherapies in aquaculture, and more broadly contributes to our understanding of the role of microbiomes in circadian health of vertebrates.85h9CE3kvpyMkhkCbi-Bj-Video

Comparing the gut microbiome along the gastrointestinal tract of three sympatric species of wild rodents

Host–microbe interactions within the gastrointestinal tract (GIT) play a pivotal role in shaping host physiology, ecology, and life history. However, these interactions vary across gut regions due to changes in the physical environment or host immune system activity, thereby altering the microbial community. Each animal species may harbor their own unique microbial community due to host species-specific ecological traits such as dietary habits, micro-habitat preferences, and mating behavior as well as physiological traits. While the gut microbiota in wild animals has received much attention over the last decade, most studies comparing closely related species only utilized fecal or colon samples. In this study, we first compared the gut microbial community from the small intestine, cecum, colon, and rectum within three sympatric species of wild rodents (i.e. Apodemus speciosus, A. argenteus, and Myodes rufocanus). We then compared each gut region among host species to determine the effect of both gut region and host species on the gut microbiota. We found that the small intestine harbored a unique microbiome as compared to the lower GIT in all three host species, with the genus Lactobacillus in particular having higher abundance in the small intestine of all three host species. There were clear interspecific differences in the microbiome within all gut regions, although some similarity in alpha diversity and community structure within the small intestine was found. Finally, fecal samples may be appropriate for studying the lower GIT in these species, but not the small intestine.

Alzheimer's Disease: Protective Effects of Mycobacterium vaccae, a Soil-Derived Mycobacterium with Anti-Inflammatory and Anti-Tubercular Properties, on the Proteomic Profiles of Plasma and Cerebrospinal Fluid in Rats.

Alzheimer's disease (AD) is an inflammatory neurodegenerative disease that may be associated with prior bacterial infections. Microbial "old friends" can suppress exaggerated inflammation in response to disease-causing infections or increase clearance of pathogens such as Mycobacterium tuberculosis, which causes tuberculosis (TB). One such "old friend" is Mycobacterium vaccae NCTC 11659, a soil-derived bacterium that has been proposed either as a vaccine for prevention of TB, or as immunotherapy for the treatment of TB when used alongside first line anti-TB drug treatment. The goal of this study was to use a hypothesis generating approach to explore the effects of M. vaccae on physiological changes in the plasma and cerebrospinal fluid (CSF). Liquid chromatography-tandem mass spectrometry-based proteomics were performed in plasma and CSF of adult male rats after immunization with a heat-killed preparation of M. vaccae NCTC 11659 or borate-buffered saline vehicle. Gene enrichment analysis and analysis of protein-protein interactions were performed to integrate physiological network changes in plasma and CSF. We used RT-qPCR to assess immune and metabolic gene expression changes in the hippocampus. In both plasma and CSF, immunization with M. vaccae increased proteins associated with immune activation and downregulated proteins corresponding to lipid (including phospholipid and cholesterol) metabolism. Immunization with M. vaccae also increased hippocampal expression of interleukin-4 (IL-4) mRNA, implicating anti-inflammatory effects in the central nervous system. M. vaccae alters host immune activity and lipid metabolism. These data are consistent with the hypothesis that microbe-host interactions may protect against possible infection-induced, inflammation-related cognitive impairments.

Akt Inhibition Is Associated With Favorable Immune Profile Changes Within the Tumor Microenvironment of Hormone Receptor Positive, HER2 Negative Breast Cancer.

Background: The PI3K/Akt/mTOR pathway in part impacts tumorigenesis through modulation of host immune activity. To assess the effects of Akt inhibition on the tumor micro-environment (TME), we analyzed tumor tissue from patients with operable hormone receptor positive, HER2 negative breast cancer (BC) treated on a presurgical trial with the Akt inhibitor MK-2206.Methods: Quantitative multiplex immunofluorescence (qmIF) was performed using CD3, CD8, CD4, FOXP3, CD68, and pancytokeratin on biopsy and surgical specimens of MK-2206 and untreated, control patients. nanoString was performed on surgical specimens to assess mRNA expression from MK-2206-treated vs. control patients.Results: Increased CD3+CD8+ density was observed in post vs. pre-treatment tissue in the MK-2206-treated vs. control patients (87 vs. 0.2%, p < 0.05). MK-2206 was associated with greater expression of interferon signaling genes (e.g., IFI6, p < 0.05) and lower expression of myeloid genes (CD163, p < 0.05) on differential expression and gene set enrichment analyses. Greater expression of pro-apoptotic genes (e.g., BAD) were associated with MK-2206 treatment (p < 0.05).Conclusion: Akt inhibition in operable BC was associated with a favorable immune profile in the TME, including increased CD3+CD8+ density and greater expression of interferon genes. Additional studies are warranted, as this may provide rationale for combining Akt inhibition with immunotherapy.

Gut microbiota dysregulation of fatty acid metabolism accelerates ages-mediated knee joint degeneration

Purpose: Joint degeneration is a prominent feature of skeletal deterioration and disability in senile people. Gut microbiota dysregulation is shown to disturb host immune reaction and metabolic activity, augmenting tissue deterioration in various pathological contexts. Little has been verified what biological role of gut microbiota may play during age-mediated joint damage. The study is aimed to investigate whether gut microbiome was relevant to joint integrity in senile mice.

Review on Application of Oncolytic Virotherapy of Cancer Cells in Veterinary Medicine

Oncolytic virotherapy is using oncolytic viruses (OVs) which selectively infect and kill cancer cells. Oncolytic viruses represent a highly targeted approach to established cancer that brings a multimechanistics approach and an acceptable safety profile to patients with a variety of cancers. A variety number of viruses have been developed as oncolytic virotherapeutics, including Adenovirus, Vaccinia virus, Herpesvirus, Measles , Coxsackie A virus, Newcastle disease virus, and Reovirus . Anticancer viruses can now be engineered to selectively attack cancer cells, spare normal tissue, awaken the host immune system and reverse immunosuppression in the tumor microenvironment. But virotherapy is not a cure on its own. Research suggests that virotherapies will serve to supplement chemotherapy, radiation therapy or immunotherapy. Combinations of OV with cytotoxic agents are feasible and safe, with the potential of transient immune supperssion of the host in order to increase viral access to the tumor and provide time for viral oncolysis to exceed the tumor’s replicative potential. Granulocyte macrophage colony stimulating factor as an immune-stimulatory cytokine boosts host immune activity through the infiltration of dendritic cells and CD4+ and CD8+ T cells at tumor sites. Concomitants to human, cancer is the leading cause of death in companion animals such as dogs and cats. The most important challenges for the successful clinical use of OVs in veterinary practice are reduction of viral toxicity, optimization of virus delivery to tumor, and enhancement of viral spread throughout the tumor mass. The multifactorial, interplay can be determined by the complex interactions between the tumor and its microenvironment, the virus, and the host immune response. Yet, there is promise that OVs will soon be a new, powerful treatment option for veterinary patients with cancer. Hence, sound understanding of the biology of OVs and its application in veterinary medicine require. Keywords: Cancer, Combination-therapy, Oncolytic virotherapy , Virus. DOI: 10.7176/ALST/79-04 Publication date: March 31 st 2020

Abstract P4-10-32: Commensal gut microbiota influences efficacy of trastuzumab in patients with HER2-positive breast carcinoma

Abstract Although the clinical benefit of trastuzumab for the management of HER2-positive breast carcinomas (BCs) has been largely demonstrated, many women, even those reported to have tumors potentially most sensitive to trastuzumab (e.g., HER2-enriched by PAM50 and with infiltrating immune cells) do not respond to this agent. The relevance of immunity in the cytotoxic mechanism of action of trastuzumab supports the notion that the anti-tumor effect of this monoclonal antibody depends on host immune system activity. Since gut commensal bacteria reportedly contribute to the development and maintenance of the immune system and have immunomodulatory effects, we investigated whether a relationship between gut microbiota composition and the response to trastuzumab exists in patients with HER2-positive BC. Stool samples were collected from 18 patients with primary HER2-positive BCs before the outset of neoadjuvant trastuzumab-based chemotherapy and analyzed by 16S rRNA gene profiling using Illumina Miseq platform. Gut microbiota β-diversity analysis by UniFrac algorithm revealed a heterogeneous microbiota composition mainly due to differences in the relative abundance of Bacteroides, Faecalibacterium and a genus belonging to Ruminococcaceae family. Unsupervised analysis identified two microbiota clusters that significantly discriminated patients according to pathological complete response (pCR) (p=0.0128, by Fisher test). No association between microbiota clusters and PAM50 molecular classification of tumor biopsies, as evaluated by gene expression, was observed. Moreover, HER2-enriched cases were distributed in the two microbiota clusters based on trastuzumab response. Differences in the intestinal microbiota between responsive (R) and non-responsive (NR) patients were assessed by LEfSe analysis: a significant higher and lower abundance of Clostridiales taxonomic order and Bacteroides taxonomic genus, respectively, was foundin R as compared to NR patients. Immune genes expressed in tumor biopsies that were found significantly correlated with these bacteria mainly belong to innate and adaptive immune response and cellular response to tumor necrosis factor pathways. To investigate the causal role of gut microbiota in trastuzumab benefit, FVB mice bearing syngeneic mammary carcinoma overexpressing human HER2 were transplanted with fecal material from R and NR patients after intestinal flora depletion by the use of an antibiotic cocktail. The mouse response to trastuzumab treatment recapitulated the response observed in patients from which stool derived. The obtained results support the contribution of gut microbiota in trastuzumab activity by influencing tumor immune microenvironment, independently of tumor intrinsic molecular characteristics. These data represent the proof-of-concept that manipulating gut microbes in resistant patients could be a new strategy to improve the response to trastuzumab. Supported by AIRC Citation Format: Elda Tagliabue, Martina Di Modica, Giorgio Gargari, Viola Regondi, Arianna Bonizzi, Stefania Arioli, Fabio Corsi, Simone Guglielmetti, Tiziana Triulzi. Commensal gut microbiota influences efficacy of trastuzumab in patients with HER2-positive breast carcinoma [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P4-10-32.

Combination of host immune metabolic biomarkers for the PD-1 blockade cancer immunotherapy.

BACKGROUNDCurrent clinical biomarkers for the programmed cell death 1 (PD-1) blockade therapy are insufficient because they rely only on the tumor properties, such as programmed cell death ligand 1 expression frequency and tumor mutation burden. Identifying reliable, responsive biomarkers based on the host immunity is necessary to improve the predictive values.METHODSWe investigated levels of plasma metabolites and T cell properties, including energy metabolism markers, in the blood of patients with non-small cell lung cancer before and after treatment with nivolumab (n = 55). Predictive values of combination markers statistically selected were evaluated by cross-validation and linear discriminant analysis on discovery and validation cohorts, respectively. Correlation between plasma metabolites and T cell markers was investigated.RESULTSThe 4 metabolites derived from the microbiome (hippuric acid), fatty acid oxidation (butyrylcarnitine), and redox (cystine and glutathione disulfide) provided high response probability (AUC = 0.91). Similarly, a combination of 4 T cell markers, those related to mitochondrial activation (PPARγ coactivator 1 expression and ROS), and the frequencies of CD8+PD-1hi and CD4+ T cells demonstrated even higher prediction value (AUC = 0.96). Among the pool of selected markers, the 4 T cell markers were exclusively selected as the highest predictive combination, probably because of their linkage to the abovementioned metabolite markers. In a prospective validation set (n = 24), these 4 cellular markers showed a high accuracy rate for clinical responses of patients (AUC = 0.92).CONCLUSIONCombination of biomarkers reflecting host immune activity is quite valuable for responder prediction.FUNDINGAMED under grant numbers 18cm0106302h0003, 18gm0710012h0105, and 18lk1403006h0002; the Tang Prize Foundation; and JSPS KAKENHI grant numbers JP16H06149, 17K19593, and 19K17673.

Seborrheic dermatitis—Looking beyond Malassezia

Seborrhoeic Dermatitis (SD) is a very common chronic and/or relapsing inflammatory skin disorder whose pathophysiology remains poorly understood. Yeast of the genus Malassezia has long been regarded as a main predisposing factor, even though causal relationship has not been firmly established. Additional predisposing factors have been described, including sebaceous activity, host immunity (especially HIV infection), epidermal barrier integrity, skin microbiota, endocrine and neurologic factors, and environmental influences. Genetic studies in humans and mouse models-with particularly interesting insights from examining the Mpzl3 knockout mice and their SD-like skin phenotype, and patients carrying a ZNF750 mutation-highlight defects in host immunity, epidermal barrier and sebaceous activity. After synthesizing key evidence from the literature, we propose that intrinsic host factors, such as changes in the amount or composition of sebum and/or defective epidermal barrier, rather than Malassezia, may form the basis of SD pathobiology. We argue that these intrinsic changes provide favourable conditions for the commensal Malassezia to over-colonize and elicit host inflammatory response. Aberrant host immune activity or failure to clear skin microbes may bypass the initial epidermal or sebaceous abnormalities. We delineate specific future clinical investigations, complemented by studies in suitable SD animal models, that dissect the roles of different epidermal compartments and immune components as well as their crosstalk and interactions with the skin microbiota during the process of SD. This research perspective beyond the conventional Malassezia-centric view of SD pathogenesis is expected to enable the development of better therapeutic interventions for the management of recurrent SD.

Abstract P2-03-01: Akt inhibition associated with change in immunophenotype of tumor microenvironment (TME) in breast cancer (BC)

Abstract Background: The PI3K/Akt/mTOR pathway is a known oncogenic pathway in BC. In addition, this pathway has demonstrated capacity to modulate host immune activity and may indirectly affect tumorigenesis. Clinicopathologic studies have demonstrated that lymphocyte density within the TME is predictive of chemosensitivity and improved prognosis in BC, while myeloid infiltration may play a deleterious role. To define the impact of Akt inhibition on the TME, we analyzed tumor tissue from patients (pts) with early-stage BC treated with single agent MK-2206, an Akt inhibitor, enrolled on a presurgical trial (NCT01319539). Methods: Quantitative immunofluorescence (qmIF) was performed for CD3, CD8, CD4, FOXP3, CD68, Pancytokeratin on 4uM sections from biopsy and surgical specimens of MK-2206 (n=5) and control (n=5) pts. Images were analyzed using Vectra/inForm software (PerkinElmer), allowing for multiparameter phenotyping. Transcriptomic analysis was performed on surgical specimens to assess if differences exist in mRNA expression of tumor-associated and immune genes between pts treated with MK-2206 (n=5) and untreated matched controls (n=5) (nanoString). Statistical analysis was performed using t-Test, NetBID, and multiple comparison analysis by Benjamini-Hochberg. Gene set enrichment analysis (GSEA) was performed within R with gene sets from Molecular Signatures Database (Hallmark, Reactome, GO). Results: On qmIF analysis, MK-2206 treated pts exhibited a significant increase in median cytotoxic T-cell (CD3+CD8+, CTL) density between pretreatment biopsy and surgical excision specimens, as compared to the control pts (87% vs.0.2%, p &amp;lt; 0.05). Mean macrophage density (CD68+) was numerically lower in surgical specimens of pts who received MK-2206 vs. control pts, although CD68+ infiltration was overall low (p=ns). mRNA expression supports in vivo activity of MK-2206 with lower expression levels of cell cycle, proliferation and anti-apoptotic genes (e.g. CTNNB1, CCND2, BAX) and greater expression of pro-apoptotic genes (e.g. BAD) associated with MK-2206 treatment (raw p-value &amp;lt;0.05). Additionally, greater mRNA copy number of IGF1R, a receptor tyrosine kinase (RTK) previously identified as upregulated in BC in the context of Akt inhibition, was found in post-MK-2206 surgical specimens as compared to control, non-MK-2206 specimens (raw p-value &amp;lt;0.05). MK-2206 was also associated with reduced expression of myeloid markers (e.g. CSF1R, CD163) (raw p-value &amp;lt;0.05). By GSEA, canonical gene sets related to interferon signaling were increased in post-MK-2206 specimens as compared to non-MK-2206 specimens, whereas monocyte chemotaxis genes were decreased in treated pts (adj p-value &amp;lt;0.05). RT-PCR is currently underway to compare biopsy and surgical specimens for a subset of RTK, immune and apoptosis related genes identified above. Conclusion: mRNA and qmIF analysis suggest that Akt inhibition, may increase interferon signaling, CTL density, and decrease myeloid infiltration. Thus, Akt inhibition may promote a favorable TME. At present, there are both FDA approved and investigational agents that target the PI3K/mTOR pathway. Further investigation is warranted to understand the impact of Akt inhibition on the TME and potential therapeutic implications. Citation Format: Marks DK, Gartrell RD, Pan Q, El Asmar M, Hart TD, Esancy CL, Lu Y, Yu J, Hibshoosh H, Connolly E, Kalinsky K, Saenger YM. Akt inhibition associated with change in immunophenotype of tumor microenvironment (TME) in breast cancer (BC) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-03-01.