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Cancers avoid immune surveillance through an array of mechanisms, including perturbation of HLA class I antigen presentation. Merkel cell carcinoma (MCC) is an aggressive, HLA-I-low, neuroendocrine carcinoma of the skin often caused by the Merkel cell polyomavirus (MCPyV). Through the characterization of 11 newly generated MCC patient-derived cell lines, we identified transcriptional suppression of several class I antigen presentation genes. To systematically identify regulators of HLA-I loss in MCC, we performed parallel, genome-scale, gain- and loss-of-function screens in a patient-derived MCPyV-positive cell line and identified MYCL and the non-canonical Polycomb repressive complex 1.1 (PRC1.1) as HLA-I repressors. We observed physical interaction of MYCL with the MCPyV small T viral antigen, supporting a mechanism of virally mediated HLA-I suppression. We further identify the PRC1.1 component USP7 as a pharmacologic target to restore HLA-I expression in MCC.

CD8 + T cell responses are the foundation of the recent clinical success of immunotherapy in oncologic indications. Although checkpoint inhibitors have enhanced the activity of existing CD8 + T cell responses, therapeutic approaches to generate Ag-specific CD8 + T cell responses have had limited success. Here, we demonstrate that cytosolic delivery of Ag through microfluidic squeezing enables MHC class I presentation to CD8 + T cells by diverse cell types. In murine dendritic cells (DCs), squeezed DCs were ∼1000-fold more potent at eliciting CD8 + T cell responses than DCs cross-presenting the same amount of protein Ag. The approach also enabled engineering of less conventional APCs, such as T cells, for effective priming of CD8 + T cells in vitro and in vivo. Mixtures of immune cells, such as murine splenocytes, also elicited CD8 + T cell responses in vivo when squeezed with Ag. We demonstrate that squeezing enables effective MHC class I presentation by human DCs, T cells, B cells, and PBMCs and that, in clinical scale formats, the system can squeeze up to 2 billion cells per minute. Using the human papillomavirus 16 (HPV16) murine model, TC-1, we demonstrate that squeezed B cells, T cells, and unfractionated splenocytes elicit antitumor immunity and correlate with an influx of HPV-specific CD8 + T cells such that >80% of CD8s in the tumor were HPV specific. Together, these findings demonstrate the potential of cytosolic Ag delivery to drive robust CD8 + T cell responses and illustrate the potential for an autologous cell-based vaccine with minimal turnaround time for patients., (Copyright © 2022 by The American Association of Immunologists, Inc.)

The tumor immune microenvironment plays a critical role in cancer progression and response to immunotherapy in clear cell renal cell carcinoma (ccRCC), yet the composition and phenotypic states of immune cells in this tumor are incompletely characterized. We performed single-cell RNA and T cell receptor sequencing on 164,722 individual cells from tumor and adjacent non-tumor tissue in patients with ccRCC across disease stages: early, locally advanced, and advanced/metastatic. Terminally exhausted CD8 + T cells were enriched in metastatic disease and were restricted in T cell receptor diversity. Within the myeloid compartment, pro-inflammatory macrophages were decreased, and suppressive M2-like macrophages were increased in advanced disease. Terminally exhausted CD8 + T cells and M2-like macrophages co-occurred in advanced disease and expressed ligands and receptors that support T cell dysfunction and M2-like polarization. This immune dysfunction circuit is associated with a worse prognosis in external cohorts and identifies potentially targetable immune inhibitory pathways in ccRCC., Competing Interests: Declaration of interests D.A.B. reports nonfinancial support from Bristol Myers Squibb, honoraria from LM Education/Exchange Services, and personal fees from Octane Global, Defined Health, Dedham Group, Adept Field Solutions, Slingshot Insights, Blueprint Partnerships, Charles River Associates, Trinity Group, and Insight Strategy, outside of the submitted work. S.H.G. has patents licensed to Novalgen Inc, outside of the submitted work. Z.B. reports nonfinancial support from Bristol Myers Squibb and Genentech/imCore. D.B.K. has acted as an advisor to and has received consulting fees from Neon Therapeutics and owns equity in Agenus, Armata pharmaceuticals, Breakbio, Biomarin Pharmaceutical, Bristol Myers Squibb, Celldex Therapeutics, Chinook Therapeutics, Editas Medicine, Exelixis, Gilead Sciences, IMV, Lexicon Pharmaceuticals, Moderna, and Regeneron Pharmaceuticals. K.M.M. reports research support from Bristol Myers Squibb. B.A.M. reports consulting fees from Bayer, Astellas, Astra Zeneca, Seattle Genetics, Dendreon, Calithera, Exelixis, Nektar, Pfizer, Janssen, Genentech, Eisai, and EMD Serono, and research support to DFCI from Bristol Myers Squibb, Calithera, Exelixis, Seattle Genetics. D.F.M. has received consulting fees from Bristol Myers Squibb, Pfizer, Merck, Alkermes, EMD Serono, Eli Lilly, Iovance, and Eisai, and research support from Bristol Myers Squibb, Merck, Genentech, Pfizer, Exelixis, X4 Pharma, and Alkermes. S.A.S. reports nonfinancial support from Bristol Myers Squibb outside the submitted work. S.A.S. previously advised and has received consulting fees from Neon Therapeutics. S.A.S. reports nonfinancial support from Bristol Myers Squibb, and equity in Agenus Inc., Agios Pharmaceuticals, Breakbio Corp., Bristol Myers Squibb, and Lumos Pharma, outside the submitted work. S.S. reported personal fees from Merck, AstraZeneca, Bristol Myers Squibb, CRISPR Therapeutics AG, AACR, and NCI, grants from Bristol Myers Squibb, AstraZeneca, Novartis, and Exelixis, and royalties from Biogenex. A.H.S. has patents/pending royalties on the PD-1 pathway from Roche and Novartis. A.H.S. is on advisory boards for Bicara, Janssen Immunology, Surface Oncology, Elstar, SQZ Biotechnologies, Elpiscience, Selecta, and Monopteros, and consults for Novartis. A.H.S. has received research funding from AbbVie, Novartis, Roche, UCB, Ipsen, Quark, and Merck. D.F.M. reports personal fees from Bristol Myers Squibb, Pfizer, Merck, Novartis, Exelixis, Array BioPharm, Genentech, Alkermes, Jounce Therapeutics, X4 Pharma, Peloton, EMD Serono, and Eli Lilly, and research support from Bristol Myers Squibb, Prometheus Laboratories, Merck, Genentech, Pfizer, Exelixis, Novartis, X4 Pharma, Alkermes, and Peloton. T.K.C. reports grants and personal fees from Astra Zeneca; personal fees from Bayer; grants and personal fees from Bristol Myers Squibb; personal fees from Cerulean; grants and personal fees from Eisai; personal fees from Foundation Medicine Inc.; grants and personal fees from Exelixis; grants and personal fees from Genentech; personal fees from Roche; grants and personal fees from GlaxoSmithKline; grants and personal fees from Merck, from Novartis, Peloton, and Pfizer; personal fees from Prometheus Labs; grants and personal fees from Corvus; personal fees from Ipsen; grants from Tracon; and grants from Astellas outside the submitted work. The other authors declare no potential conflicts of interest. C.J.W. is an equity holder of BioNTech., (Copyright © 2021 Elsevier Inc. All rights reserved.)

This article reports on how the increasing number of AIDS patients is having a significant impact on the delivery of healthcare services. Healthcare workers need to learn how to provide medical care for persons with AIDS as well as how to interact with and relate to them. Workers who have accurate information regarding the transmission of AIDS report more positive responses. In addition to didactic educational efforts hospital workers need explicit education on the psychosocial issues related to AIDS including such issues as fears of contagion, homosexuality, and death anxiety. Ethnic and cultural differences of both the AIDS population and healthcare workers must be addressed to relieve feelings of risk, stress, and discomfort. Each healthcare setting must determine the most effective means to educate all levels of staff on a continual basis.