Epigenetic silencing of immune-related genes is a striking feature of the cancer genome that occurs in the process of tumorigenesis. This phenomena impacts antigen processing and antigen presentation by tumor cells and facilitates evasion of immunosurveillance. Further modulation of the tumor microenvironment by altered expression of immunosuppressive cytokines impairs antigen-presenting cells and cytolytic T-cell function. The potential reversal of immunosuppression by epigenetic modulation is therefore a promising and versatile therapeutic approach to reinstate endogenous immune recognition and tumor lysis. Pre-clinical studies have identified multiple elements of the immune system that can be modulated by epigenetic mechanisms and result in improved antigen presentation, effector T-cell function, and breakdown of suppressor mechanisms. Recent clinical studies are utilizing epigenetic therapies prior to, or in combination with, immune therapies to improve clinical outcomes.

Vaccines may help reduce the growing incidence of fungal infections in immune-suppressed patients. We have found that, even in the absence of CD4+ T-cell help, vaccine-induced CD8+ T cells persist and confer resistance against Blastomyces dermatitidis and Histoplasma capsulatum. Type 1 cytokines contribute to that resistance, but they also are dispensable. Although the role of T helper 17 cells in immunity to fungi is debated, IL-17 producing CD8+ T cells (Tc17 cells) have not been investigated. Here, we show that Tc17 cells are indispensable in antifungal vaccine immunity in hosts lacking CD4+ T cells. Tc17 cells are induced upon vaccination, recruited to the lung on pulmonary infection, and act non-redundantly in mediating protection in a manner that requires neutrophils. Tc17 cells did not influence type I immunity, nor did the lack of IL-12 signaling augment Tc17 cells, indicating a distinct lineage and function. IL-6 was required for Tc17 differentiation and immunity, but IL-1R1 and Dectin-1 signaling was unexpectedly dispensable. Tc17 cells expressed surface CXCR3 and CCR6, but only the latter was essential in recruitment to the lung. Although IL-17 producing T cells are believed to be short-lived, effector Tc17 cells expressed low levels of KLRG1 and high levels of the transcription factor TCF-1, predicting their long-term survival and stem-cell like behavior. Our work has implications for designing vaccines against fungal infections in immune suppressed patients.

Key Points We describe a novel, druggable pathway that controls myeloma growth through macrophages in the myeloma microenvironment. Macrophages are dominant orchestrators of the inflammatory milieu of the myeloma niche.

Individuals who are immunocompromised, including AIDS patients with few CD4 + T cells, are at increased risk for opportunistic fungal infections. The incidence of such infections is increasing worldwide, meaning that the need for antifungal vaccines is increasing. Although CD4 + T cells play a dominant role in resistance to many pathogenic fungal infections, we have previously shown that vaccination can induce protective antifungal CD8 + T cell immunity in the absence of CD4 + T cells. However, it has not been determined whether vaccine-induced antifungal CD8 + T cell memory can be maintained in the absence of CD4 + T cell help. Here, we have shown in a mouse model of vaccination against blastomycosis that antifungal memory CD8 + T cells are maintained in the absence of CD4 + T cells without loss of numbers or function for at least 6 months and that the cells protect against infection. Using a system that enabled us to induce and track antigen-specific, antifungal CD8 + T cells, we found that such cells were maintained for at least 5 months upon transfer into naive mice lacking both CD4 + T cells and persistent fungal antigen. Additionally, fungal vaccination induced a profile of transcription factors functionally linked with persistent memory in CD8 + T cells. Thus, unlike bacteria and viruses, fungi elicit long-term CD8 + T cell memory that is maintained without CD4 + T cell help or persistent antigen. This has implications for the development of novel antifungal vaccine strategies effective in immunocompromised patients.

PURPOSE There is a critical clinical need for new predictive and pharmacodynamic biomarkers that evaluate pathway activity in patients treated with targeted therapies. A microscale platform known as VERSA (Versatile Exclusion-based Rare Sample Analysis) was developed to integrate readouts across protein, mRNA and DNA in Circulating Tumor Cells (CTCs) for a comprehensive analysis of the Androgen Receptor (AR) signaling pathway. EXPERIMENTAL DESIGN Utilizing exclusion based sample preparation principles, a handheld chip was developed to perform CTC capture, enumeration, quantification and subcellular localization of proteins and extraction of mRNA and DNA. This technology was validated across integrated endpoints in cell lines and a cohort of patients with castrate resistant prostate cancer (CRPC) treated with AR targeted therapies and chemotherapies. RESULTS The VERSA was validated in cell lines to analyze AR protein expression, nuclear localization and gene expression targets. When applied to a cohort of patients, radiographic progression was predicted by the presence of multiple AR splice variants and activity in the canonical AR signaling pathway. AR protein expression and nuclear localization identified phenotypic heterogeneity. Next Generation Sequencing with the FoundationOne panel detected copy number changes and point mutations. Longitudinal analysis of CTCs identified acquisition of multiple AR variants during targeted treatments and chemotherapy. CONCLUSIONS Complex mechanisms of resistance to AR targeted therapies, across RNA, DNA and protein endpoints, exist in patients with CRPC and can be quantified in CTCs. Interrogation of the AR signaling pathway revealed distinct patterns relevant to tumor progression and can serve as pharmacodynamic biomarkers for targeted therapies.

Rising rates of Histoplasma capsulatum infection are an emerging problem among the rapidly growing population of immune-compromised individuals. Although there is a growing understanding of systemic immunity against Histoplasma, little is known about the local granulomatous response, which is an important component in the control of infection. The focus of this article is the characterization of Histoplasma-induced granulomas. Five days after i.p. infection, infected macrophage appear in the liver and lung; however, no granulomas are apparent. Two days later, well-formed sarcoid granulomas are abundant in the lung and liver of infected mice, which contain all visible Histoplasma. Granulomas are dominated by macrophage and lymphocytes. Most of the Histoplasma and most of the apoptotic cells are found in the center of the lesions. We isolated liver granulomas at multiple time points after infection and analyzed the cellular composition, TCR gene usage, and cytokine production of granuloma-infiltrating cells. The lesions contain both CD4+ and CD8+ T cell subsets, and T cells are the primary source of IFN-γ and IL-17. The main source of local TNF-α is macrophage. Chemokines are produced by both infiltrating macrophage and lymphocytes. Dendritic cells are present in granulomas; however, T cell expansion seems to occur systemically because TCR usage is very heterogeneous even at the level of individual lesions. This study is the first direct examination of host cellular responses in the Histoplasma-induced granuloma representing the specific interface between host and pathogen. Our studies will allow further analysis of key elements of host Histoplasma interactions at the site of chronic infection.

BackgroundExpression of programmed-death ligand 1 (PD-L1) in non-small cell lung cancer (NSCLC) is typically evaluated through invasive biopsies; however, recent advances in the identification of circulating tumor cells (CTCs) may be a less invasive method to assay tumor cells for these purposes. These liquid biopsies rely on accurate identification of CTCs from the diverse populations in the blood, where some tumor cells share characteristics with normal blood cells. While many blood cells can be excluded by their high expression of CD45, neutrophils and other immature myeloid subsets have low to absent expression of CD45 and also express PD-L1. Furthermore, cytokeratin is typically used to identify CTCs, but neutrophils may stain non-specifically for intracellular antibodies, including cytokeratin, thus preventing accurate evaluation of PD-L1 expression on tumor cells. This holds even greater significance when evaluating PD-L1 in epithelial cell adhesion molecule (EpCAM) positive and EpCAM negative CTCs (as in epithelial-mesenchymal transition (EMT)).MethodsTo evaluate the impact of CTC misidentification on PD-L1 evaluation, we utilized CD11b to identify myeloid cells. CTCs were isolated from patients with metastatic NSCLC using EpCAM, MUC1 or Vimentin capture antibodies and exclusion-based sample preparation (ESP) technology.ResultsLarge populations of CD11b+CD45lo cells were identified in buffy coats and stained non-specifically for intracellular antibodies including cytokeratin. The amount of CD11b+ cells misidentified as CTCs varied among patients; accounting for 33–100% of traditionally identified CTCs. Cells captured with vimentin had a higher frequency of CD11b+ cells at 41%, compared to 20% and 18% with MUC1 or EpCAM, respectively. Cells misidentified as CTCs ultimately skewed PD-L1 expression to varying degrees across patient samples.ConclusionsInterfering myeloid populations can be differentiated from true CTCs with additional staining criteria, thus improving the specificity of CTC identification and the accuracy of biomarker evaluation.

The amount of inflammatory cytokines is a major determinant for the development of sepsis in very-low-birth-weight (VLBW) neonates. We investigated whether variants of tumor necrosis factor-α, interleukin (IL)-1β, IL-4 receptor α-chain, IL-6 and IL-10 genes, associated with altered cytokine production, might influence the risk and complications of sepsis in VLBW infants. We determined the presence of these genetic variants in dried blood samples of 33 septic, 35 infected and 35 healthy VLBW neonates by PCR and RFLP methods and analyzed their association with the risk and complications of sepsis. The frequencies of genetic variants did not differ in uninfected and in infected infants with or without sepsis. Moreover, none of the studied complications was associated with carrier state of any of genetic variants. Four of the 5 septic neonates with disseminated intravascular coagulation, however, carried simultaneously the variants of IL-1β and IL-10 genes. We concluded that these genetic polymorphisms do not influence the risk and course of sepsis in VLBW neonates.