The cysteinyl leukotrienes, leukotriene (LT) C4, LTD4, and LTE4, are lipid mediators that have been implicated in the pathogenesis of several inflammatory processes, including asthma. The human LTD4 receptor, CysLT1R, was recently cloned and characterized. We had previously shown that HL-60 cells differentiated toward the eosinophilic lineage (HL-60/eos) developed specific functional LTD4 receptors. The present work was undertaken to study the potential modulation of CysLT1R expression in HL-60/eos by IL-5, an important regulator of eosinophil function. Here, we report that IL-5 rapidly up-regulates CysLT1R mRNA expression, with consequently enhanced CysLT1R protein expression and function in HL-60/eos. CysLT1R mRNA expression was augmented 2- to 15-fold following treatment with IL-5 (1–20 ng/ml). The effect was seen after 2 h, was maximal by 4 h, and maintained at 8 h. Although CysLT1R mRNA was constitutively expressed in undifferentiated HL-60 cells, its expression was not modulated by IL-5 in the absence of differentiation. Differentiated HL-60/eos cells pretreated with IL-5 (10 ng/ml) for 24 h showed enhanced CysLT1R expression on the cell surface, as assessed by flow cytometry using a polyclonal anti-CysLT1R Ab. They also showed enhanced responsiveness to LTD4, but not to LTB4 or platelet-activating factor, in terms of Ca2+ mobilization, and augmented the chemotactic response to LTD4. Our findings suggest a possible mechanism by which IL-5 can modulate eosinophil functions and particularly their responsiveness to LTD4, and thus contribute to the pathogenesis of asthma and allergic diseases.
The foundation of personalized cancer therapy is teaching a patient’s own immune system to directly kill the cancer cells. Vaccination against tumor antigens is one method being explored to generate immune responses against tumors, and may be particularly effective in conjunction with therapies currently in the clinic, such as checkpoint inhibition. Identification of antigens for use in a vaccine is the pinch point of this method, and many algorithms have been developed in an attempt to predict what epitopes will be both presented and immunogenic. Importantly, both public (common to multiple individuals/cancer types) and private (single individual) epitopes may contribute to the development of effective vaccines. Experimental identification of presented and immunogenic epitopes is crucial to building effective anti-cancer vaccines. Using immunopeptidome profiling, we have narrowed a collection of published potential neoantigens to those which were presented by MHC class I in the CT26 mouse colorectal cancer cell line. These peptides were synthesized and used to immunize BALB/c mice. The immunogenicity of the peptide mix was then evaluated by ELIspot to assess IFN-gamma responses in immunized mice. These experiments support a complete workflow for selection of potential cancer neoantigens which experimentally exhibit both MHC presentation and immunogenicity. Citation Format: Seeta Nyayapathy, Richard Jones, Michael Ford, Micah Doty, Julie M. Rumble. CT26 neoantigen presentation and immunogenicity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2996.
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