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1.
Cell Rep ; 39(13): 111009, 2022 Jun 28.
Article in English | MEDLINE | ID: covidwho-1944463

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron BA.2 sub-lineage has gained in proportion relative to BA.1. Because spike (S) protein variations may underlie differences in their pathobiology, here we determine cryoelectron microscopy (cryo-EM) structures of the BA.2 S ectodomain and compare these with previously determined BA.1 S structures. BA.2 receptor-binding domain (RBD) mutations induce remodeling of the RBD structure, resulting in tighter packing and improved thermostability. Interprotomer RBD interactions are enhanced in the closed (or 3-RBD-down) BA.2 S, while the fusion peptide is less accessible to antibodies than in BA.1. Binding and pseudovirus neutralization assays reveal extensive immune evasion while defining epitopes of two outer RBD face-binding antibodies, DH1044 and DH1193, that neutralize both BA.1 and BA.2. Taken together, our results indicate that stabilization of the closed state through interprotomer RBD-RBD packing is a hallmark of the Omicron variant and show differences in key functional regions in the BA.1 and BA.2 S proteins.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Viral , Cryoelectron Microscopy , Humans , Receptors, Virus/metabolism , Spike Glycoprotein, Coronavirus
2.
Cell Rep ; 38(11): 110514, 2022 03 15.
Article in English | MEDLINE | ID: covidwho-1739598

ABSTRACT

The success of nucleoside-modified mRNAs in lipid nanoparticles (mRNA-LNP) as COVID-19 vaccines heralded a new era of vaccine development. For HIV-1, multivalent envelope (Env) trimer protein nanoparticles are superior immunogens compared with trimers alone for priming of broadly neutralizing antibody (bnAb) B cell lineages. The successful expression of complex multivalent nanoparticle immunogens with mRNAs has not been demonstrated. Here, we show that mRNAs can encode antigenic Env trimers on ferritin nanoparticles that initiate bnAb precursor B cell expansion and induce serum autologous tier 2 neutralizing activity in bnAb precursor VH + VL knock-in mice. Next-generation sequencing demonstrates acquisition of critical mutations, and monoclonal antibodies that neutralize heterologous HIV-1 isolates are isolated. Thus, mRNA-LNP can encode complex immunogens and may be of use in design of germline-targeting and sequential boosting immunogens for HIV-1 vaccine development.


Subject(s)
AIDS Vaccines , COVID-19 , HIV-1 , Nanoparticles , Animals , Antibodies, Monoclonal , Antibodies, Neutralizing , COVID-19 Vaccines , Epitopes , Ferritins/genetics , HIV Antibodies , Humans , Liposomes , Mice , RNA, Messenger , env Gene Products, Human Immunodeficiency Virus/genetics
3.
2021.
Preprint in English | Other preprints | ID: ppcovidwho-295545

ABSTRACT

SUMMARY The success of nucleoside-modified mRNAs in lipid nanoparticles (mRNA-LNP) as COVID-19 vaccines heralded a new era of vaccine development. For HIV-1, multivalent envelope (Env) trimer protein nanoparticles are superior immunogens compared to trimers alone for priming of broadly neutralizing antibody (bnAb) B cell lineages. The successful expression of complex multivalent nanoparticle immunogens with mRNAs has not been demonstrated. Here we show that mRNAs can encode antigenic Env trimers on ferritin nanoparticles that initiate bnAb precursor B cell expansion and induce serum autologous tier 2 neutralizing activity in bnAb precursor VH + VL knock-in mice. Next generation sequencing demonstrated acquisition of critical mutations, and monoclonal antibodies that neutralized heterologous HIV-1 isolates were isolated. Thus, mRNA- LNP can encode complex immunogens and are of use in design of germline-targeting and sequential boosting immunogens for HIV-1 vaccine development.

4.
Cell ; 184(16): 4203-4219.e32, 2021 08 05.
Article in English | MEDLINE | ID: covidwho-1275187

ABSTRACT

SARS-CoV-2-neutralizing antibodies (NAbs) protect against COVID-19. A concern regarding SARS-CoV-2 antibodies is whether they mediate disease enhancement. Here, we isolated NAbs against the receptor-binding domain (RBD) or the N-terminal domain (NTD) of SARS-CoV-2 spike from individuals with acute or convalescent SARS-CoV-2 or a history of SARS-CoV infection. Cryo-electron microscopy of RBD and NTD antibodies demonstrated function-specific modes of binding. Select RBD NAbs also demonstrated Fc receptor-γ (FcγR)-mediated enhancement of virus infection in vitro, while five non-neutralizing NTD antibodies mediated FcγR-independent in vitro infection enhancement. However, both types of infection-enhancing antibodies protected from SARS-CoV-2 replication in monkeys and mice. Three of 46 monkeys infused with enhancing antibodies had higher lung inflammation scores compared to controls. One monkey had alveolar edema and elevated bronchoalveolar lavage inflammatory cytokines. Thus, while in vitro antibody-enhanced infection does not necessarily herald enhanced infection in vivo, increased lung inflammation can rarely occur in SARS-CoV-2 antibody-infused macaques.


Subject(s)
Antibodies, Neutralizing/immunology , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/immunology , Animals , Antibodies, Viral/immunology , Bronchoalveolar Lavage Fluid/chemistry , COVID-19/pathology , COVID-19/virology , Cytokines/metabolism , Female , Haplorhini , Humans , Lung/pathology , Lung/virology , Male , Mice , Mice, Inbred BALB C , Protein Domains , RNA, Guide/metabolism , Receptors, IgG/metabolism , SARS-CoV-2/isolation & purification , Spike Glycoprotein, Coronavirus/chemistry , Viral Load , Virus Replication
5.
Nat Struct Mol Biol ; 28(2): 128-131, 2021 02.
Article in English | MEDLINE | ID: covidwho-1010060

ABSTRACT

The SARS-CoV-2 spike (S) protein, a primary target for COVID-19 vaccine development, presents its receptor binding domain in two conformations, the receptor-accessible 'up' or receptor-inaccessible 'down' states. Here we report that the commonly used stabilized S ectodomain construct '2P' is sensitive to cold temperatures, and this cold sensitivity is abrogated in a 'down' state-stabilized ectodomain. Our findings will impact structural, functional and vaccine studies that use the SARS-CoV-2 S ectodomain.


Subject(s)
Spike Glycoprotein, Coronavirus/chemistry , Antibodies, Viral/chemistry , COVID-19 Vaccines/chemistry , Cold Temperature , Cryoelectron Microscopy , Enzyme-Linked Immunosorbent Assay , Humans , Protein Denaturation , Protein Domains , Protein Stability , Spike Glycoprotein, Coronavirus/ultrastructure , Surface Plasmon Resonance
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