Development of a Prognostic Model for Ovarian Cancer Patients Based on Novel Immune Microenvironment Related Genes

Ovarian cancer (OV) has become the most lethal gynecological cancer. However, its treatment methods and staging system are far from ideal. In the present study, taking the advantage of large-scale public cohorts, we extracted a list of immune-related prognostic genes that differentially expressed in tumor and normal ovarian tissues. Importantly, an individualized immune-related gene based prognostic model (IPM) for OV patients were developed. Furthermore, we validated our IPM in Gene Expression Omnibus (GEO) repository and compared the immune landscape and pathways between high-risk and low-risk groups. The results of our study can serve as an important model to identify the immune subset of patients and has potential for use in immune therapeutic selection and patient management.

Salmonella-Based Therapy Targeting Indoleamine 2,3-Dioxygenase Restructures the Immune Contexture to Improve Checkpoint Blockade Efficacy

Therapeutic options for non-small cell lung cancer (NSCLC) treatment have changed dramatically in recent years with the advent of novel immunotherapeutic approaches. Among these, immune checkpoint blockade (ICB) using monoclonal antibodies has shown tremendous promise in approximately 20% of patients. In order to better predict patients that will respond to ICB treatment, biomarkers such as tumor-associated CD8+ T cell frequency, tumor checkpoint protein status and mutational burden have been utilized, however, with mixed success. In this study, we hypothesized that significantly altering the suppressive tumor immune landscape in NSCLC could potentially improve ICB efficacy. Using sub-therapeutic doses of our Salmonella typhimurium-based therapy targeting the suppressive molecule indoleamine 2,3-dioxygenase (shIDO-ST) in tumor-bearing mice, we observed dramatic changes in immune subset phenotypes that included increases in antigen presentation markers, decreased regulatory T cell frequency and overall reduced checkpoint protein expression. Combination shIDO-ST treatment with anti-PD-1/CTLA-4 antibodies enhanced tumor growth control, compared to either treatment alone, which was associated with significant intratumoral infiltration by CD8+ and CD4+ T cells. Ultimately, we show that increases in antigen presentation markers and infiltration by T cells is correlated with significantly increased survival in NSCLC patients. These results suggest that the success of ICB therapy may be more accurately predicted by taking into account multiple factors such as potential for antigen presentation and immune subset repertoire in addition to markers already being considered. Alternatively, combination treatment with agents such as shIDO-ST could be used to create a more conducive tumor microenvironment for improving responses to ICB.

290 Cytokine and immune subset signatures in patients with various solid and hematological malignancies treated with oncolytic vaccinia virus delivered by autologous stromal vascular fraction cells

BackgroundThe development of oncolytic viruses for the treatment of cancer has been significantly hampered by their rapid clearance in circulation due to complement and antibody-mediated neutralization. In our recent first-in-human Phase I clinical trial, we evaluated the safety and feasibility of our approach to enhance virus delivery and improve tumor targeting by utilizing an autologous stromal vascular fraction (SVF) based cell delivery system. Patient sample analysis demonstrated that patients could be stratified based on the level of vaccinia virus amplification in vivo, as evidenced by analysis of persistent viral DNA in the blood.MethodsIn the current study, we evaluated the immunomodulatory potential of vaccinia virus delivered by autologous stromal vascular fraction (SVF)-derived cells and attempted to identify immunological correlates of successful vaccinia virus amplification in vivo. To this end, we performed an extensive time-course analysis of cytokines in patients‘ plasma as well as various peripheral blood immune subpopulations using Luminex multi-analyte profiling and multiparameter flow cytometry, respectively. We also analyzed the impact of this therapeutic approach on the innate and adaptive immune subpopulations, including NK cells, myeloid cells, as well as effector, regulatory and memory T cells.ResultsTherapy with SFV-delivered oncolytic vaccinia virus induced a coordinated activation of cytokine, T cell and NK cell responses in patients as early as 1 day after treatment, which peaked around 1-week and lasted for up to 1-month post treatment. The ability of the oncolytic virus to effectively amplify in cancer patients correlated with significant changes of multiple innate (NK) and adaptive (T cell) immunological parameters. Interestingly, patient stratification into groups with transient versus persistent viral DNA was linked to opposing and mutually exclusive patterns of robust activation of NK versus T cell responses, respectively. Our study also identified intriguing cytokine and immune subset frequency signatures present at baseline and associated with successful amplification and persistence of oncolytic vaccinia virus in vivo.ConclusionsOverall, this study establishes the timeline of treatment-related immunological changes and identifies biomarkers present at baseline and potential immunological correlates associated with the persistence of virus amplification in vivo. Therefore, our findings provide new insights into the role of interpatient immunological variability and will contribute to the proper evaluation of the therapeutic potency of oncolytic virotherapy in future clinical trials.

Formation and Maintenance of Tissue Resident Memory CD8+ T Cells after Viral Infection

Tissue resident memory (TRM) CD8 T cells comprise a memory population that forms in peripheral, non-lymphoid tissues after an infection that does not recirculate into the bloodstream or other tissues. TRM cells often recognize conserved peptide epitopes shared among different strains of a pathogen and so offer a protective role upon secondary encounter with the same or related pathogens. Several recent studies have begun to shed light on the intrinsic and extrinsic factors regulating TRM. In addition, work is being done to understand how canonical “markers” of TRM actually affect the function of these cells. Many of these markers regulate the generation or persistence of these TRM cells, an important point of study due to the differences in persistence of TRM between tissues, which may impact future vaccine development to cater towards these important differences. In this review, we will discuss recent advances in TRM biology that may lead to strategies designed to promote this important protective immune subset.

Revealing the Immune Population Hierarchy Using Novel Interactive Visualization Tools, a Comparison of Methods: Sunburst, viSNE, and Spade on Mass Cytometry Data

The development of new technologies for high-parameter data has resulted in a critical bottleneck: identification of immune subsets is restricted to expert-based analysis, focusing on post-acquisition characterization of cell populations. Identification of cell subsets in flow cytometry has primarily focused on manual analysis, despite the fact that computational tools have proven useful for high-parameter and cross-sample comparisons. Sharing well-annotated data improves transparency and facilitates vital reproduction of results by external groups. Adoption of these new tools for immune subset discovery requires thorough collaborative investigation and validation of identified cell populations. To this end, in this study we compare the ease of discovery of immune subsets by comparing analysis through the use of three visualization tools: the sunburst hierarchy, the SPADE tree, and dimensionality reduction using viSNE. The sunburst hierarchy is a visual and interactive representation of traditional manual gating, whereas the SPADE tree is a semi-automated clustering and visualization tool for identification of cell subsets. viSNE allows interaction with high parameter data in the context of two-dimensional space where gating can be accomplished. In this study, we demonstrate the ability to automatically elucidate many immune subsets using Cytobank via an iterative analytic approach, combining computational tools (viSNE and SPADE) to recapitulate manually derived cell subsets. Disclosures Chen: Cytobank, Inc: Employment, Equity Ownership. Kotecha:Cytobank, Inc: Employment, Equity Ownership.

CD8 count measurement has independent prognostic significance in individuals with AIDS-Kaposi sarcoma

20500 Background: We recently published a prognostic index for Acquired Immunodeficiency Syndrome (AIDS)-associated Kaposi sarcoma (KS) diagnosed in the era of highly active antiretroviral therapy (HAART) based on clinical and routine laboratory characteristics. Because immune subset measurement is often performed in human immunodeficiency virus (HIV) positive individuals, we examined whether these were predictive of mortality independently of the prognostic index, or could predict time to progression of KS. Methods: We performed univariate and multivariate Cox regression analyses on a dataset of 326 individuals with AIDS-KS to identify immune subset covariates predictive of overall survival and time to progression. Adaptive (CD8 T cell and CD19 B cell) and innate (CD16/56 natural killer cell) immune parameters were studied by flow cytometry. Results: In univariate analyses all 3 immune subsets had significant effects on overall survival (p < 0.025). In multivariate analyses including the prognostic index, only CD8 counts remained significant (p = 0.026) although its effect on the overall prognostic index is small. An increase of 100 cells/mm3 in the CD8 count confers a 5% improvement in overall survival. Individuals with a higher CD8 count did not have an increased time to progression. Patients who were already on HAART at the time of KS diagnosis did not have a shorter time to progression than those who were antiretroviral naïve at KS diagnosis. Conclusions: The CD8 count appears to provide independent prognostic information in individuals with AIDS-KS. Measurement of the CD8 count is clinically useful in patients with KS. No significant financial relationships to disclose.

Prognostic Significance of Immune Subset Measurement in Individuals With AIDS-Associated Kaposi's Sarcoma

Purpose A prognostic index for AIDS-associated Kaposi's sarcoma (KS) diagnosed in the era of highly active antiretroviral therapy (HAART) was based on routine clinical and laboratory characteristics. Because immune subset measurement is often performed in HIV-positive individuals, we examined whether these were predictive of mortality independently of the prognostic index, or could predict time to progression of KS. Patients and Methods We performed univariate and multivariate Cox regression analyses on a data set of 326 individuals with AIDS-associated KS to identify immune subset covariates predictive of overall survival and time to progression. Adaptive (CD8 T cell and CD19 B cell) and innate (CD16/56 natural-killer cell) immune parameters were studied by flow cytometry. Results In univariate analyses, all three immune subsets had significant effects on overall survival (P < .025). In multivariate analyses including the prognostic index, only CD8 counts remained significant (P = .026), although its effect on the overall prognostic index is small. An increase of 100 cells/mm3 in the CD8 count confers a 5% improvement in overall survival. Individuals with a higher CD8 count did not have an increased time to progression. Patients who were already on HAART at the time of KS diagnosis did not have a shorter time to progression than those who were antiretroviral naïve at KS diagnosis. Conclusion The CD8 count appears to provide independent prognostic information in individuals with AIDS-associated KS. Measurement of the CD8 count is clinically useful in patients with KS.