{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,23]],"date-time":"2026-07-23T06:06:06Z","timestamp":1784786766996,"version":"3.55.0"},"reference-count":49,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,7,23]],"date-time":"2026-07-23T00:00:00Z","timestamp":1784764800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Immunol."],"abstract":"<jats:p>Myeloid cells play a key role in cancer-associated immunosuppression because their accumulation and reprogramming inhibit antitumor responses and support tumor growth. To modulate their activity, we targeted Fc\u03b3 receptors (Fc\u03b3Rs), which are broadly expressed in myeloid subsets. Since low-affinity Fc\u03b3 receptor IIb (Fc\u03b3RIIb) mediates inhibitory signaling, we designed an immunotherapy active at a low dose to limit binding to Fc\u03b3RIIb while retaining interaction with higher-affinity Fc\u03b3Rs. We engineered an Fc-based fusion protein, whose activity is potentiated by its ability to engage both Fc\u03b3Rs and a coreceptor, Heparan Sulfate Proteoglycan (HSPGs). This immunotherapy, named Fc-T54, combines an HSPG-ligand, named T54, with human IgG1-Fc. Compared with Fc, Fc-T54 displayed superior binding to Fc\u03b3 receptor IIa (Fc\u03b3RIIa), Fc\u03b3 receptor IIIa (Fc\u03b3RIIIa) and enhanced interactions with human leukocytes, including neutrophils, B-lymphocytes, as well as with monocytes, and dendritic cells (DCs) within peripheral blood mononuclear cells. Functionally, Fc-T54 increased monocyte\/macrophage and B-cell numbers, reduced neutrophil abundance, and boosted DC activation in both the human and murine systems. Subcutaneous administration of low-dose Fc-T54 - or its murine surrogate - inhibits tumor growth in immune-deserted and immune-excluded mouse models and synergizes with anti-PD-1 therapy in an immune-inflamed model. Tumor microenvironment analysis in the bladder cancer model revealed that the immunotherapy decreased the proportion of granulocytic myeloid-derived suppressor cells while increasing CD8+ T cells and natural killer cells, promoting a microenvironment more prone to tumor control. This Fc\u03b3R\/HSPG-engaging immunotherapy, administered subcutaneously, offers a novel approach to modulate the myeloid compartment and improve outcomes for ICI-resistant, deserted\/excluded tumors, and for inflamed tumors when used in combination regimens.<\/jats:p>","DOI":"10.3389\/fimmu.2026.1734778","type":"journal-article","created":{"date-parts":[[2026,7,23]],"date-time":"2026-07-23T05:39:19Z","timestamp":1784785159000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["A low-dose immunotherapy targeting Fc gamma Receptors and heparan sulfate proteoglycan to impact myeloid cells and control cancers with diverse immunosuppressive profiles"],"prefix":"10.3389","volume":"17","author":[{"given":"Nora Kakwata-Nkor","family":"Deluce","sequence":"first","affiliation":[{"name":"Blue Bees Therapeutics, Parc Club-Orsay Universit\u00e9","place":["Orsay, France"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Elodie","family":"Creton","sequence":"additional","affiliation":[{"name":"Blue Bees Therapeutics, Parc Club-Orsay Universit\u00e9","place":["Orsay, France"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alexandra","family":"Savatier","sequence":"additional","affiliation":[{"name":"D\u00e9partement M\u00e9dicaments et Technologies pour la Sant\u00e9, Universit\u00e9 Paris Saclay, CEA, INRAE, SPI","place":["Gif-sur-Yvette, France"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Honorine","family":"Lucchi","sequence":"additional","affiliation":[{"name":"Blue Bees Therapeutics, Parc Club-Orsay Universit\u00e9","place":["Orsay, France"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Laureen","family":"Bardouillet","sequence":"additional","affiliation":[{"name":"Blue Bees Therapeutics, Parc Club-Orsay Universit\u00e9","place":["Orsay, France"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Oscar Pereira","family":"Ramos","sequence":"additional","affiliation":[{"name":"D\u00e9partement M\u00e9dicaments et Technologies pour la Sant\u00e9, Universit\u00e9 Paris Saclay, CEA, INRAE, SPI","place":["Gif-sur-Yvette, France"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Philippe","family":"Berthon","sequence":"additional","affiliation":[{"name":"Blue Bees Therapeutics, Parc Club-Orsay Universit\u00e9","place":["Orsay, France"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Michel","family":"L\u00e9onetti","sequence":"additional","affiliation":[{"name":"D\u00e9partement M\u00e9dicaments et Technologies pour la Sant\u00e9, Universit\u00e9 Paris Saclay, CEA, INRAE, SPI","place":["Gif-sur-Yvette, France"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,7,23]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","DOI":"10.3389\/fimmu.2022.887781","article-title":"The role of myeloid cells in GBM immunosuppression","volume":"13","author":"Lin","year":"2022","journal-title":"Front Immunol"},{"key":"B2","doi-asserted-by":"publisher","DOI":"10.3389\/fcell.2020.00351","article-title":"Friend or foe? 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