Transfer of SARS-CoV-2 nucleocapsid protein to uninfected epithelial cells induces antibody-mediated complement deposition

Jamal Fahoum¹, Maria Billan², Julia K Varga³, Dan Padawer⁴, Yelena Britan-Rosich⁵, Maya Elgrably-Weiss³, Pallabi Basu⁶, Miri Stolovich-Rain², Leah Baraz⁷, Einav Cohen-Kfir⁸, Sujata Kumari⁹, Esther Oiknine-Djian¹⁰, Manoj Kumar⁸, Orly Zelig¹¹, Guy Mayer¹², Michail N Isupov¹³, Dana G Wolf¹⁴, Shoshy Altuvia³, Reuven Wiener¹⁵, Ora Schueler-Furman¹⁶, Alexander Rouvinski¹⁷

Affiliations

¹ Department of Biochemistry, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel; Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel.
² Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel; The Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel.
³ Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel.
⁴ Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel; Institute of Pulmonary Medicine, Hebrew University-Hadassah Medical Center, Jerusalem, Israel.
⁵ Barry Skolnick Biosafety Level 3 (BSL3) Unit, Core Research Facility, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.
⁶ Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel; Dove Laboratory, Boston Children's Hospital, Boston, MA 02115, USA.
⁷ Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel; The Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel; Department of Medical Laboratory Sciences, Jerusalem Multidisciplinary College, Jerusalem, Israel.
⁸ Department of Biochemistry, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel.
⁹ Department of Biochemistry, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel; Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel; The Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel.
¹⁰ Clinical Virology Unit, Hadassah Hebrew University Medical Center, Israel Hadassah Hebrew University Medical Center, Jerusalem, Israel.
¹¹ Blood Bank, Hebrew University-Hadassah Medical Center, Jerusalem, Israel.
¹² The Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, Israel.
¹³ The Henry Wellcome Building for Biocatalysis, Biosciences, University of Exeter, Exeter, UK.
¹⁴ Clinical Virology Unit, Hadassah Hebrew University Medical Center, Israel Hadassah Hebrew University Medical Center, Jerusalem, Israel; Lautenberg Centre for Immunology and Cancer Research, The Institute for Medical Research Israel-Canada (IMRIC), Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.
¹⁵ Department of Biochemistry, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel. Electronic address: reuvenw@ekmd.huji.ac.il.
¹⁶ Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel. Electronic address: ora.furman-schueler@mail.huji.ac.il.
¹⁷ Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel; The Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel. Electronic address: alexander.rouvinski@mail.huji.ac.il.

PMID: 40343796
DOI: 10.1016/j.celrep.2025.115512

Free article

Transfer of SARS-CoV-2 nucleocapsid protein to uninfected epithelial cells induces antibody-mediated complement deposition

Jamal Fahoum et al. Cell Rep. 2025.

Free article

. 2025 May 27;44(5):115512.

doi: 10.1016/j.celrep.2025.115512. Epub 2025 May 8.

Authors

Affiliations

¹ Department of Biochemistry, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel; Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel.
² Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel; The Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel.
³ Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel.
⁴ Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel; Institute of Pulmonary Medicine, Hebrew University-Hadassah Medical Center, Jerusalem, Israel.
⁵ Barry Skolnick Biosafety Level 3 (BSL3) Unit, Core Research Facility, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.
⁶ Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel; Dove Laboratory, Boston Children's Hospital, Boston, MA 02115, USA.
⁷ Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel; The Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel; Department of Medical Laboratory Sciences, Jerusalem Multidisciplinary College, Jerusalem, Israel.
⁸ Department of Biochemistry, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel.
⁹ Department of Biochemistry, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel; Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel; The Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel.
¹⁰ Clinical Virology Unit, Hadassah Hebrew University Medical Center, Israel Hadassah Hebrew University Medical Center, Jerusalem, Israel.
¹¹ Blood Bank, Hebrew University-Hadassah Medical Center, Jerusalem, Israel.
¹² The Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, Israel.
¹³ The Henry Wellcome Building for Biocatalysis, Biosciences, University of Exeter, Exeter, UK.
¹⁴ Clinical Virology Unit, Hadassah Hebrew University Medical Center, Israel Hadassah Hebrew University Medical Center, Jerusalem, Israel; Lautenberg Centre for Immunology and Cancer Research, The Institute for Medical Research Israel-Canada (IMRIC), Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.
¹⁵ Department of Biochemistry, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel. Electronic address: reuvenw@ekmd.huji.ac.il.
¹⁶ Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel. Electronic address: ora.furman-schueler@mail.huji.ac.il.
¹⁷ Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel; The Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel. Electronic address: alexander.rouvinski@mail.huji.ac.il.

PMID: 40343796
DOI: 10.1016/j.celrep.2025.115512

Abstract

SARS-CoV-2 infection triggers a strong antibody response toward nucleocapsid protein (NP), suggesting its extracellular presence beyond intravirion RNA binding. Our co-culture experiments show NP decorates infected and proximal uninfected cell surfaces. We propose a mechanism whereby extracellular NP on uninfected cells contributes to COVID-19 pathogenicity. We show that NP binds to cell-surface sulfated glycosaminoglycans using its RNA-binding sites, facilitated by the flexible, positively charged linker. Coating uninfected lung-derived cells with NP attracted anti-NP IgG from lung fluids and sera of COVID-19 patients. Immune recognition was significantly higher in moderate versus mild COVID-19. Binding of anti-NP IgG in sera generated clusters, triggering C3b deposition via the classical complement pathway on SARS-CoV-2 non-susceptible cells co-cultured with infected cells. The heparin analog enoxaparin outcompeted NP binding, rescuing cells from anti-NP IgG-mediated complement deposition. Our findings reveal how extracellular NP may exacerbate COVID-19 damage and suggest preventative therapy avenues.

Keywords: C3b complement deposition; COVID-19 severity; CP: Immunology; SARS-CoV-2 antibodies; SARS-Cov-2 Nucleocapsid protein; classical complement pathway; electrostatic interactions; enoxaparin; flexible linker; heparan sulfate proteoglycans; sulfated glycosaminoglycans.

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Conflict of interest statement

Declaration of interests The authors declare no competing interests.

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Transfer of SARS-CoV-2 nucleocapsid protein to uninfected epithelial cells induces antibody-mediated complement deposition

Affiliations

Transfer of SARS-CoV-2 nucleocapsid protein to uninfected epithelial cells induces antibody-mediated complement deposition

Authors

Affiliations

Abstract

Conflict of interest statement

MeSH terms

Substances

LinkOut - more resources

Full Text Sources

Medical

Miscellaneous