Understanding the Role of B cells in Lung Cancer

Tumor infiltrating B lymphocytes (TIL-Bs), that include B cells and plasma cells are increasingly recognized as favorable prognostic markers in multiple cancer types. The precise mechanisms underlying TIL-B associated anti-tumor immunity is an active area of investigation. Here, we identified CD79A transcript levels as a reliable quantifier of B lymphocytes. Using this marker in the cancer genome atlas (TCGA) and Gene tissue expression (GTEx) to assess transcriptomic data for 16 distinct tumors and normal tissues respectively, from a total of nearly 10,000 patients, we demonstrate that significant tumor B cell infiltration correlated with survival for some but not all tumor types. CD79A is a stronger predictor of overall survival (OS) in Non-small cell lung cancer (NSCLC) than CD8A transcripts. Further, leveraging published single cell RNA sequencing (scRNA-seq) data from NSCLC, we identified the presence and enrichment of unique CD11c expressing TIL-Bs in tumor tissue from treatment-naïve NSCLC patients, compared to normal adjacent tissue and peripheral blood. In the tumor environment these CD11c+ TIL-Bs, when compared to CD11c- B cells, were found to be preferentially localized near CD4+ T cells. Antigen recall with/without T cell help, mimicked in vitro by stimulation of freshly isolated TIL-Bs with anti-IgG with/without CD40 agonist resulted in a strong expansion of CD11c+ B cells and their rapid differentiation into plasmablasts and their precursors. Furthermore, the BCR-mediated expansion of CD11c+ TIL-Bs was associated with secretion of effector cytokines, including IL-12, IL-21, and TNF-a, that are known to enhance anti-tumor immunity. Taken together, we demonstrate that this novel population of CD11c+ TIL-B’s can actively respond to antigen and/or CD4 T cell help, identifying a potentially new cell subset to harness in anti-cancer therapeutic approaches and/or a potential novel prognostic biomarker for cancer outcome prognosis

Delivery of self-amplifying RNA vaccines in in vitro reconstituted virus-like particles.

Many mRNA-based vaccines have been investigated for their specific potential to activate dendritic cells (DCs), the highly-specialized antigen-presenting cells of the immune system that play a key role in inducing effective CD4+ and CD8+ T-cell responses. In this paper we report a new vaccine/gene delivery platform that demonstrates the benefits of using a self-amplifying ("replicon") mRNA that is protected in a viral-protein capsid. Purified capsid protein from the plant virus Cowpea Chlorotic Mottle Virus (CCMV) is used to in vitro assemble monodisperse virus-like particles (VLPs) containing reporter proteins (e.g., Luciferase or eYFP) or the tandem-repeat model antigen SIINFEKL in RNA gene form, coupled to the RNA-dependent RNA polymerase from the Nodamura insect virus. Incubation of immature DCs with these VLPs results in increased activation of maturation markers - CD80, CD86 and MHC-II - and enhanced RNA replication levels, relative to incubation with unpackaged replicon mRNA. Higher RNA uptake/replication and enhanced DC activation were detected in a dose-dependent manner when the CCMV-VLPs were pre-incubated with anti-CCMV antibodies. In all experiments the expression of maturation markers correlates with the RNA levels of the DCs. Overall, these studies demonstrate that: VLP protection enhances mRNA uptake by DCs; coupling replicons to the gene of interest increases RNA and protein levels in the cell; and the presence of anti-VLP antibodies enhances mRNA levels and activation of DCs in vitro. Finally, preliminary in vivo experiments involving mouse vaccinations with SIINFEKL-replicon VLPs indicate a small but significant increase in antigen-specific T cells that are doubly positive for IFN and TFN induction

AHR Activation Is Protective against Colitis Driven by T Cells in Humanized Mice

Summary: Existing therapies for inflammatory bowel disease that are based on broad suppression of inflammation result in variable clinical benefit and unwanted side effects. A potential therapeutic approach for promoting immune tolerance is the in vivo induction of regulatory T cells (Tregs). Here we report that activation of the aryl hydrocarbon receptor using the non-toxic agonist 2-(1′H-indole-3′-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE) induces human Tregs in vitro that suppress effector T cells through a mechanism mediated by CD39 and Granzyme B. We then developed a humanized murine system whereby human CD4+ T cells drive colitis upon exposure to 2,4,6-trinitrobenzenesulfonic acid and assessed ITE as a potential therapeutic. ITE administration ameliorated colitis in humanized mice with increased CD39, Granzyme B, and IL10-secreting human Tregs. These results develop an experimental model to investigate human CD4+ T responses in vivo and identify the non-toxic AHR agonist ITE as a potential therapy for promoting immune tolerance in the intestine. : Therapeutic approaches aimed at expanding regulatory T cells in the gut to promote immune tolerance in patients with inflammatory bowel disease (IBD) are of clinical significance. Goettel et al. establish a humanized murine model of IBD driven by human T cells and find that activation of AHR by the non-toxic agonist ITE can prevent experimental colitis. Keywords: AHR, treg, humanized mice, IBD, IT