Olatz Zenarruzabeitia1, Joana Vitallé2, Iñigo Terrén2, Ane Orrantia2, Itziar Astigarraga3, Leire Dopazo4, Carlos Gonzalez5, Laura Santos-Díez4, Carlos Tutau6, Pedro M Gamboa7, Agurtzane Bilbao4, Francisco Borrego8. 1. Immunopathology Group, Biocruces Bizkaia Health Research Institute, Barakaldo, Spain. Electronic address: olatz.zenarruzabeitiabelaustegui@osakidetza.eus. 2. Immunopathology Group, Biocruces Bizkaia Health Research Institute, Barakaldo, Spain. 3. Pediatric Oncology Group, Biocruces Bizkaia Health Research Institute, Barakaldo, Spain; Pediatrics Service, Cruces University Hospital, Barakaldo, Spain; Department of Pediatrics, Faculty of Medicine and Nursing, University of the Basque Country, Leioa, Spain. 4. Immunopathology Group, Biocruces Bizkaia Health Research Institute, Barakaldo, Spain; Pediatrics Service, Cruces University Hospital, Barakaldo, Spain. 5. Department of Pediatrics, Faculty of Medicine and Nursing, University of the Basque Country, Leioa, Spain; Pediatrics Service, Basurto University Hospital, Bilbao, Spain. 6. Pediatrics Service, Cruces University Hospital, Barakaldo, Spain. 7. Immunopathology Group, Biocruces Bizkaia Health Research Institute, Barakaldo, Spain; Allergology Service, Cruces University Hospital, Barakaldo, Spain. 8. Immunopathology Group, Biocruces Bizkaia Health Research Institute, Barakaldo, Spain; Ikerbasque, Basque Foundation for Science, Bilbao, Spain; Basque Center for Transfusion and Human Tissues, Galdakao, Spain. Electronic address: francisco.borregorabasco@osakidetza.eus.
Abstract
BACKGROUND: Basophils express high-affinity IgE receptors (FcεRI), which play an essential role in allergic diseases. It is important to characterize new cell-surface receptors that modulate IgE-mediated basophil activation threshold to design promising immunomodulatory therapies. OBJECTIVES: We sought to analyze the expression of CD300 receptors on human basophils and their implication in IgE-mediated basophil activation processes. METHODS: Blood samples from healthy subjects and patients with cow's milk allergy were collected through the Basque Biobank under an institutional review board-approved protocol. PBMCs were obtained by means of density centrifugation, basophils were purified with a specific isolation kit, and phenotypic and functional studies were performed by using flow cytometry. RESULTS: We demonstrate that basophils express the activating receptor CD300c, which is specifically upregulated in response to IL-3. CD300c works as a costimulatory molecule during IgE-mediated basophil activation, as shown by a significant increase in degranulation and cytokine production when basophils are activated in the presence of CD300c cross-linking compared with activation through the IgE/FcεRI axis alone. Coligation of FcεRI and CD300c increased intracellular calcium mobilization and phosphorylation of signaling intermediates evoked only by FcεRI ligation. We show that the natural ligands of CD300c, phosphatidylserine and phosphatidylethanolamine, modulate IgE-mediated basophil activation. Furthermore, we have observed that CD300c expression in children with cow's milk allergy is increased compared with that in healthy control subjects and that the intensity of expression correlates with the severity of the hypersensitivity symptoms. CONCLUSION: CD300c could be considered a biomarker and therapeutic target in patients with IgE-mediated allergic diseases because it seems to be involved in the modulation of IgE-mediated basophil activation.
BACKGROUND: Basophils express high-affinity IgE receptors (FcεRI), which play an essential role in allergic diseases. It is important to characterize new cell-surface receptors that modulate IgE-mediated basophil activation threshold to design promising immunomodulatory therapies. OBJECTIVES: We sought to analyze the expression of CD300 receptors on human basophils and their implication in IgE-mediated basophil activation processes. METHODS: Blood samples from healthy subjects and patients with cow's milk allergy were collected through the Basque Biobank under an institutional review board-approved protocol. PBMCs were obtained by means of density centrifugation, basophils were purified with a specific isolation kit, and phenotypic and functional studies were performed by using flow cytometry. RESULTS: We demonstrate that basophils express the activating receptor CD300c, which is specifically upregulated in response to IL-3. CD300c works as a costimulatory molecule during IgE-mediated basophil activation, as shown by a significant increase in degranulation and cytokine production when basophils are activated in the presence of CD300c cross-linking compared with activation through the IgE/FcεRI axis alone. Coligation of FcεRI and CD300c increased intracellular calcium mobilization and phosphorylation of signaling intermediates evoked only by FcεRI ligation. We show that the natural ligands of CD300c, phosphatidylserine and phosphatidylethanolamine, modulate IgE-mediated basophil activation. Furthermore, we have observed that CD300c expression in children with cow's milk allergy is increased compared with that in healthy control subjects and that the intensity of expression correlates with the severity of the hypersensitivity symptoms. CONCLUSION:CD300c could be considered a biomarker and therapeutic target in patients with IgE-mediated allergic diseases because it seems to be involved in the modulation of IgE-mediated basophil activation.
Authors: Ane Orrantia; Iñigo Terrén; Alicia Izquierdo-Lafuente; Juncal A Alonso-Cabrera; Victor Sandá; Joana Vitallé; Santiago Moreno; María Tasias; Alasne Uranga; Carmen González; Juan J Mateos; Juan C García-Ruiz; Olatz Zenarruzabeitia; Francisco Borrego Journal: iScience Date: 2020-06-20