8via
From Proteopedia
Protective effect of human non-neutralizing cross-reactive spike antibodies elicited by SARS-CoV-2 mRNA vaccination
Structural highlights
FunctionSPIKE_SARS2 attaches the virion to the cell membrane by interacting with host receptor, initiating the infection (By similarity). Binding to human ACE2 receptor and internalization of the virus into the endosomes of the host cell induces conformational changes in the Spike glycoprotein (PubMed:32142651, PubMed:32075877, PubMed:32155444). Uses also human TMPRSS2 for priming in human lung cells which is an essential step for viral entry (PubMed:32142651). Proteolysis by cathepsin CTSL may unmask the fusion peptide of S2 and activate membranes fusion within endosomes.[HAMAP-Rule:MF_04099][1] [2] [3] mediates fusion of the virion and cellular membranes by acting as a class I viral fusion protein. Under the current model, the protein has at least three conformational states: pre-fusion native state, pre-hairpin intermediate state, and post-fusion hairpin state. During viral and target cell membrane fusion, the coiled coil regions (heptad repeats) assume a trimer-of-hairpins structure, positioning the fusion peptide in close proximity to the C-terminal region of the ectodomain. The formation of this structure appears to drive apposition and subsequent fusion of viral and target cell membranes.[HAMAP-Rule:MF_04099] Acts as a viral fusion peptide which is unmasked following S2 cleavage occurring upon virus endocytosis.[HAMAP-Rule:MF_04099] Publication Abstract from PubMedNeutralizing antibodies correlate with protection against SARS-CoV-2. Recent studies, however, show that binding antibody titers, in the absence of robust neutralizing activity, also correlate with protection from disease progression. Non-neutralizing antibodies cannot directly protect from infection but may recruit effector cells thus contribute to the clearance of infected cells. Also, they often bind conserved epitopes across multiple variants. We characterized 42 human mAbs from COVID-19 vaccinated individuals. Most of these antibodies exhibited no neutralizing activity in vitro but several non-neutralizing antibodies protected against lethal challenge with SARS-CoV-2 in different animal models. A subset of those mAbs showed a clear dependence on Fc-mediated effector functions. We determined the structures of three non-neutralizing antibodies with two targeting the RBD, and one that targeting the SD1 region. Our data confirms the real-world observation in humans that non-neutralizing antibodies to SARS-CoV-2 can be protective. Protective effect and molecular mechanisms of human non-neutralizing cross-reactive spike antibodies elicited by SARS-CoV-2 mRNA vaccination.,Clark J, Hoxie I, Adelsberg DC, Sapse IA, Andreata-Santos R, Yong JS, Amanat F, Tcheou J, Raskin A, Singh G, Gonzalez-Dominguez I, Edgar JE, Bournazos S, Sun W, Carreno JM, Simon V, Ellebedy AH, Bajic G, Krammer F bioRxiv [Preprint]. 2024 Mar 1:2024.02.28.582613. doi: 10.1101/2024.02.28.582613. PMID:38464151[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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