{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"institution":[{"name":"bioRxiv"}],"indexed":{"date-parts":[[2026,9,20]],"date-time":"2026-09-20T08:13:59Z","timestamp":1789892039215,"version":"4.0.1"},"posted":{"date-parts":[[2026,5,12]]},"group-title":"Cancer Biology","reference-count":45,"publisher":"openRxiv","license":[{"start":{"date-parts":[[2026,5,12]],"date-time":"2026-05-12T00:00:00Z","timestamp":1778544000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/publicdomain\/zero\/1.0\/"}],"funder":[{"name":"Intramural Research Program of the National Institutes of Health","award":["ZIA AI000394"],"award-info":[{"award-number":["ZIA AI000394"]}]},{"name":"Intramural Research Program of the National Institutes of Health","award":["ZIA AI000622"],"award-info":[{"award-number":["ZIA AI000622"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"accepted":{"date-parts":[[2026,5,12]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                <jats:sec>\n                  <jats:title>Background<\/jats:title>\n                  <jats:p>Antibody-mediated blockade of innate receptor\u2013MHC-I interactions represents a promising strategy to enhance anti-tumor immunity, particularly against metastatic cancers resistant to conventional checkpoint inhibitors. In this study, we investigated the effects of the pan anti-MHC-I monoclonal antibody M1\/42, which targets MHC-I interactions with Ly49, selectively expressed on murine NK cell subsets.<\/jats:p>\n                <\/jats:sec>\n                <jats:sec>\n                  <jats:title>Methods<\/jats:title>\n                  <jats:p>\n                    We administered M1\/42 to mice and assayed the proliferation and activation immune cells. Anti-tumor activity of growth and metastasis of checkpoint inhibitor-resistant pancreatic ductal adenocarcoma (PDAC) and B16F10 melanoma were assessed, complemented by extensive cellular phenotypic and RNA expression analysis. Binding and cryo-electron microscopic (cryo-EM) and X-ray crystallographic structural studies of M1\/42 complexed with the mouse MHC-I molecule, H2-D\n                    <jats:sup>d<\/jats:sup>\n                    , examined the Ab interaction site in comparison with those of Ly49 inhibitory receptors.\n                  <\/jats:p>\n                <\/jats:sec>\n                <jats:sec>\n                  <jats:title>Results<\/jats:title>\n                  <jats:p>\n                    M1\/42 administration in mice robustly unleashed the proliferation and activation of natural killer (NK) cells, memory CD4\n                    <jats:sup>+<\/jats:sup>\n                    and CD8\n                    <jats:sup>+<\/jats:sup>\n                    T cells, dendritic cells, and macrophages in both lymphoid and non-lymphoid tissues, independent of Fc\u03b3 receptors. M1\/42 significantly restricted the growth and metastasis of checkpoint inhibitor\u2013resistant pancreatic ductal adenocarcinoma (PDAC) and B16F10 melanoma in the liver and lungs, accompanied by increased tumor infiltration of effector CD8\n                    <jats:sup>+<\/jats:sup>\n                    T cells, reduction of T regulatory cells, and a pro-inflammatory cytokine milieu. The anti-tumor effects of M1\/42 depend on NK cells and are associated with upregulation of genes involved in antigen processing, interferon gamma responsiveness, and Th1 cytokine production, while downregulating inhibitory PD1\/11 signaling. Structural analysis indicated that the effect of M1\/42 on Ly49\/MHC-I interactions was not due to direct steric competition.\n                  <\/jats:p>\n                <\/jats:sec>\n                <jats:sec>\n                  <jats:title>Conclusions<\/jats:title>\n                  <jats:p>Collectively, these findings demonstrate that M1\/42 unleashes coordinated innate and adaptive immune responses, overcoming tumor-induced immunosuppression and resistance to checkpoint blockade. This approach represents a paradigm shift in cancer immunotherapy, offering potential for more effective treatment of metastatic cancers that evade immune surveillance through MHC-I modulation.<\/jats:p>\n                <\/jats:sec>\n                <jats:sec>\n                  <jats:title>KEY MESSAGES<\/jats:title>\n                  <jats:sec>\n                    <jats:title>What is already known on this topic<\/jats:title>\n                    <jats:p>\n                      A pan anti-mouse MHC-I mAb (M1\/42) blocks interaction with several NK inhibitory receptors (Ly49A or Ly49C) resulting in NK cell activation and anti-viral and anti-tumor responses\n                      <jats:italic>in vitro<\/jats:italic>\n                      and\n                      <jats:italic>in vivo<\/jats:italic>\n                      . Other pan anti-human MHC-I mAbs (DX17 and W6\/32) function similarly, blocking LILRB inhibitory receptor interaction of myeloid cells and NK cells. These stimulate human immune cells in humanized mouse models.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>What this study adds<\/jats:title>\n                    <jats:p>\n                      This study analyzes the effects of the pan anti-mouse MHC-I mAb on NK and myeloid cell activation in detail, in the absence of T or B cells, and independent of FcR interaction. Additionally we analyze several mouse models of metastatic tumor progression, indicative of the progressive activation not only of the innate immune response, but also adaptive responses. The molecular mechanism of the mAb blocking of inhibitory receptors is revealed by cryo-EM and X-ray structures of M1\/42 Fab\/MHC-I (H2-D\n                      <jats:sup>d<\/jats:sup>\n                      ) complexes.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>How this study might affect research, practice, or policy<\/jats:title>\n                    <jats:p>Elucidation of the details of the inhibitory effects of the mouse pan anti-mouse MHC-I mAb provides not only a more advanced understanding of the murine model system, but suggests additional functional avenues to be explored using the parallel an anti-human MHC-I mAbs.<\/jats:p>\n                  <\/jats:sec>\n                <\/jats:sec>","DOI":"10.64898\/2026.05.07.722994","type":"posted-content","created":{"date-parts":[[2026,5,12]],"date-time":"2026-05-12T15:50:20Z","timestamp":1778601020000},"source":"Crossref","is-referenced-by-count":1,"title":["Antibody Blockade of Ly49\/MHC-I interactions enhances Innate and Adaptive Immunity Against Cancer Metastasis"],"prefix":"10.64898","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8139-7016","authenticated-orcid":false,"given":"Abir K.","family":"Panda","sequence":"first","affiliation":[{"name":"Cellular Immunology Section, Laboratory of Immune System Biology, NIAID, NIH"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Surajit","family":"Sinha","sequence":"additional","affiliation":[{"name":"Surgical Oncology Program, Center for Clinical Research, NCI, NIH"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6295-2571","authenticated-orcid":false,"given":"Kannan","family":"Natarajan","sequence":"additional","affiliation":[{"name":"Molecular Biology Section, Laboratory of Immune System Biology, NIAID, NIH"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0964-5481","authenticated-orcid":false,"given":"Jiansheng","family":"Jiang","sequence":"additional","affiliation":[{"name":"Molecular Biology Section, Laboratory of Immune System Biology, NIAID, NIH"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sruthi","family":"Chempati","sequence":"additional","affiliation":[{"name":"Cellular Immunology Section, Laboratory of Immune System Biology, NIAID, NIH"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Soha","family":"Kazmi","sequence":"additional","affiliation":[{"name":"Cellular Immunology Section, Laboratory of Immune System Biology, NIAID, NIH"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yong-Hee","family":"Kim","sequence":"additional","affiliation":[{"name":"Cellular Immunology Section, Laboratory of Immune System Biology, NIAID, NIH"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Suveena","family":"Sharma","sequence":"additional","affiliation":[{"name":"Cellular Immunology Section, Laboratory of Immune System Biology, NIAID, NIH"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Paul","family":"Schaughency","sequence":"additional","affiliation":[{"name":"Integrated Data Sciences Section, Research Technologies Branch, NIAID, NIH"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5126-6250","authenticated-orcid":false,"given":"Lisa F.","family":"Boyd","sequence":"additional","affiliation":[{"name":"Molecular Biology Section, Laboratory of Immune System Biology, NIAID, NIH"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jonathan M.","family":"Hernandez","sequence":"additional","affiliation":[{"name":"Surgical Oncology Program, Center for Clinical Research, NCI, NIH"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8530-7375","authenticated-orcid":false,"given":"David H.","family":"Margulies","sequence":"additional","affiliation":[{"name":"Molecular Biology Section, Laboratory of Immune System Biology, NIAID, NIH"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1607-4664","authenticated-orcid":false,"given":"Ethan M.","family":"Shevach","sequence":"additional","affiliation":[{"name":"Cellular Immunology Section, Laboratory of Immune System Biology, NIAID, NIH"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"54368","reference":[{"key":"2026051409451033000_2026.05.07.722994v1.1","unstructured":"Margulies DH , Natarajan K , Rossjohn J , McCluskey J . The Major Histocompatibility Complex (MHC). In: Flajnik MF , Singh NJ , Holland SM , editors. Paul\u2019s Fundamental Immunology: Wolters Kluwer; 2023. p. 571\u2013621."},{"key":"2026051409451033000_2026.05.07.722994v1.2","doi-asserted-by":"publisher","DOI":"10.1146\/annurev-genom-091212-153455"},{"key":"2026051409451033000_2026.05.07.722994v1.3","doi-asserted-by":"crossref","unstructured":"Lee MY , Jeon JW , Sievers C , Allen CT . Antigen processing and presentation in cancer immunotherapy. J Immunother Cancer. 2020;8(2).","DOI":"10.1136\/jitc-2020-001111"},{"key":"2026051409451033000_2026.05.07.722994v1.4","doi-asserted-by":"publisher","DOI":"10.1146\/annurev.immunol.20.100301.064812"},{"key":"2026051409451033000_2026.05.07.722994v1.5","doi-asserted-by":"publisher","DOI":"10.1126\/science.1198687"},{"key":"2026051409451033000_2026.05.07.722994v1.6","doi-asserted-by":"publisher","DOI":"10.1038\/s41577-020-0390-6"},{"key":"2026051409451033000_2026.05.07.722994v1.7","doi-asserted-by":"publisher","DOI":"10.1038\/icb.2010.78"},{"key":"2026051409451033000_2026.05.07.722994v1.8","doi-asserted-by":"publisher","DOI":"10.1038\/ni0508-477"},{"key":"2026051409451033000_2026.05.07.722994v1.9","doi-asserted-by":"publisher","DOI":"10.1111\/imr.12325"},{"key":"2026051409451033000_2026.05.07.722994v1.10","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.1804931115"},{"key":"2026051409451033000_2026.05.07.722994v1.11","doi-asserted-by":"publisher","DOI":"10.1038\/ni1006"},{"key":"2026051409451033000_2026.05.07.722994v1.12","doi-asserted-by":"publisher","DOI":"10.1158\/0008-5472.CAN-13-3021"},{"key":"2026051409451033000_2026.05.07.722994v1.13","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.1722374115"},{"key":"2026051409451033000_2026.05.07.722994v1.14","doi-asserted-by":"publisher","DOI":"10.1182\/blood-2008-03-143727"},{"key":"2026051409451033000_2026.05.07.722994v1.15","doi-asserted-by":"publisher","DOI":"10.1038\/ni1153"},{"key":"2026051409451033000_2026.05.07.722994v1.16","doi-asserted-by":"publisher","DOI":"10.3389\/fimmu.2014.00123"},{"key":"2026051409451033000_2026.05.07.722994v1.17","doi-asserted-by":"publisher","DOI":"10.1016\/S1471-4906(00)01802-0"},{"key":"2026051409451033000_2026.05.07.722994v1.18","doi-asserted-by":"crossref","first-page":"67","DOI":"10.1016\/j.coi.2021.03.014","article-title":"Conformational sensing of major histocompatibility complex (MHC) class I molecules by immune receptors and intracellular assembly factors","volume":"70","year":"2021","journal-title":"Curr Opin Immunol"},{"key":"2026051409451033000_2026.05.07.722994v1.19","doi-asserted-by":"publisher","DOI":"10.1038\/346476a0"},{"key":"2026051409451033000_2026.05.07.722994v1.20","doi-asserted-by":"publisher","DOI":"10.1038\/319675a0"},{"key":"2026051409451033000_2026.05.07.722994v1.21","doi-asserted-by":"publisher","DOI":"10.1126\/scisignal.abq0752"},{"key":"2026051409451033000_2026.05.07.722994v1.22","doi-asserted-by":"publisher","DOI":"10.1084\/jem.168.4.1469"},{"key":"2026051409451033000_2026.05.07.722994v1.23","doi-asserted-by":"publisher","DOI":"10.4049\/jimmunol.2000412"},{"key":"2026051409451033000_2026.05.07.722994v1.24","doi-asserted-by":"publisher","DOI":"10.1158\/2326-6066.CIR-25-0343"},{"key":"2026051409451033000_2026.05.07.722994v1.25","doi-asserted-by":"crossref","unstructured":"Jiang J , Panda AK , Natarajan K , Lei H , Sharma S , Boyd LF , et al. Structural mechanism of anti-MHC-I antibody blocking of inhibitory NK cell receptors in tumor immunity. Commun Biol. 2026;9(1).","DOI":"10.1038\/s42003-026-09641-8"},{"key":"2026051409451033000_2026.05.07.722994v1.26","doi-asserted-by":"crossref","unstructured":"Aguilar OA , Fong LK , Ishiyama K , DeGrado WF , Lanier LL . The CD3zeta adaptor structure determines functional differences between human and mouse CD16 Fc receptor signaling. J Exp Med. 2022;219(5).","DOI":"10.1084\/jem.20220022"},{"key":"2026051409451033000_2026.05.07.722994v1.27","doi-asserted-by":"publisher","DOI":"10.1002\/cpph.2"},{"key":"2026051409451033000_2026.05.07.722994v1.28","doi-asserted-by":"publisher","DOI":"10.1016\/j.immuni.2011.11.016"},{"key":"2026051409451033000_2026.05.07.722994v1.29","doi-asserted-by":"publisher","DOI":"10.1038\/s41467-021-25758-2"},{"key":"2026051409451033000_2026.05.07.722994v1.30","doi-asserted-by":"crossref","first-page":"150906","DOI":"10.1016\/j.bbrc.2024.150906","article-title":"Homeostatic self-MHC-I recognition regulates anti-metastatic function of mature lung natural killer cells","volume":"738","year":"2024","journal-title":"Biochem Biophys Res Commun"},{"key":"2026051409451033000_2026.05.07.722994v1.31","doi-asserted-by":"publisher","DOI":"10.1016\/j.ccell.2017.06.009"},{"key":"2026051409451033000_2026.05.07.722994v1.32","doi-asserted-by":"publisher","DOI":"10.1016\/j.immuni.2018.09.009"},{"key":"2026051409451033000_2026.05.07.722994v1.33","doi-asserted-by":"crossref","unstructured":"Springer TA . Cell surface differentiation in the mouse. Characterizatin of \u2018jumpin\u2019 and \u2018lineage\u2019 antigens using xenogeneic rat monoclonal antibodies. In: Kennett RH , McKearn, T.J. , Bechtol, K.E. , editor. Monoclonal Antibodies. New York: Plenum Press; 1980. p. 185\u2013217.","DOI":"10.1007\/978-1-4615-7505-4_12"},{"issue":"3","key":"2026051409451033000_2026.05.07.722994v1.34","doi-asserted-by":"crossref","first-page":"923","DOI":"10.4049\/jimmunol.127.3.923","article-title":"Characterization of an anti-H-2 monoclonal antibody and its use in large-scale antigen purification","volume":"127","year":"1981","journal-title":"J Immunol"},{"key":"2026051409451033000_2026.05.07.722994v1.35","doi-asserted-by":"crossref","unstructured":"Go S , Demetriou C , Valenzano G , Hughes S , Lanfredini S , Ferry H , et al. Tissue-resident natural killer cells support survival in pancreatic cancer through promotion of cDC1-CD8 T activity. Elife. 2024;13.","DOI":"10.7554\/eLife.92672.3"},{"key":"2026051409451033000_2026.05.07.722994v1.36","unstructured":"Sinha S , Panda AK , Xavier das Neves R , Nwosu ZC , Xu K , van Beek E , et al. Expression of IMPACT Curtails Metabolic Plasticity and Augments NK Cell Killing to Abrogate Metastatic Growth. Cancer Discov. 2025:OF1\u2013OF30."},{"key":"2026051409451033000_2026.05.07.722994v1.37","doi-asserted-by":"publisher","DOI":"10.1074\/jbc.M801526200"},{"key":"2026051409451033000_2026.05.07.722994v1.38","doi-asserted-by":"publisher","DOI":"10.1038\/45170"},{"key":"2026051409451033000_2026.05.07.722994v1.39","doi-asserted-by":"publisher","DOI":"10.1016\/S0022-2836(02)00498-9"},{"key":"2026051409451033000_2026.05.07.722994v1.40","doi-asserted-by":"publisher","DOI":"10.1074\/jbc.M116.737130"},{"key":"2026051409451033000_2026.05.07.722994v1.41","first-page":"55","article-title":"The interaction with H-2D(d) in cis is associated with a conformational change in the Ly49A NK cell receptor","volume":"2","year":"2011","journal-title":"Front Immunol"},{"key":"2026051409451033000_2026.05.07.722994v1.42","doi-asserted-by":"publisher","DOI":"10.1016\/j.immuni.2009.07.007"},{"key":"2026051409451033000_2026.05.07.722994v1.43","doi-asserted-by":"publisher","DOI":"10.1042\/BCJ20160876"},{"issue":"6","key":"2026051409451033000_2026.05.07.722994v1.44","doi-asserted-by":"crossref","first-page":"876","DOI":"10.4049\/jimmunol.2400328","article-title":"The Structural Basis for Recognition of Human Leukocyte Antigen Class I Molecules by the Pan-HLA Antibody W6\/32","volume":"213","year":"2024","journal-title":"J Immunol"},{"key":"2026051409451033000_2026.05.07.722994v1.45","doi-asserted-by":"publisher","DOI":"10.1002\/PRO.4792"}],"container-title":[],"original-title":[],"link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.64898\/2026.05.07.722994","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,14]],"date-time":"2026-05-14T16:45:21Z","timestamp":1778777121000},"score":1,"resource":{"primary":{"URL":"http:\/\/biorxiv.org\/lookup\/doi\/10.64898\/2026.05.07.722994"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,5,12]]},"references-count":45,"URL":"https:\/\/doi.org\/10.64898\/2026.05.07.722994","relation":{},"subject":[],"published":{"date-parts":[[2026,5,12]]},"subtype":"preprint"}}