Tick-borne encephalitis virus (TBEV) is a flavivirus that causes human neuroinfections and represents a growing health problem. The human monoclonal antibody T025 targets envelope protein domain III (EDIII) of TBEV and related tick-borne flaviviruses, potently neutralizing TBEV in vitro and in preclinical models, representing a promising candidate for clinical development. We demonstrate that TBEV escape in the presence of T025 or T028 (another EDIII-targeting human monoclonal antibody) results in virus variants of reduced pathogenicity, characterized by distinct sets of amino acid changes in EDII and EDIII that are jointly needed to confer resistance. EDIII substitution K311N impairs formation of a salt bridge critical for T025-epitope interaction. EDII substitution E230K is not on the T025 epitope but likely induces quaternary rearrangements of the virus surface because of repulsion of positively charged residues on the adjacent EDI. A combination of T025 and T028 prevents virus escape and improves neutralization.

• MeSH
• epitopy MeSH
• klíšťová encefalitida * MeSH
• lidé MeSH
• monoklonální protilátky MeSH
• protilátky virové MeSH
• viry klíšťové encefalitidy * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants diminishes the efficacy of vaccines and antiviral monoclonal antibodies. Continued development of immunotherapies and vaccine immunogens resilient to viral evolution is therefore necessary. Using coldspot-guided antibody discovery, a screening approach that focuses on portions of the virus spike glycoprotein that are both functionally relevant and averse to change, we identified human neutralizing antibodies to highly conserved viral epitopes. Antibody fp.006 binds the fusion peptide and cross-reacts against coronaviruses of the four genera, including the nine human coronaviruses, through recognition of a conserved motif that includes the S2' site of proteolytic cleavage. Antibody hr2.016 targets the stem helix and neutralizes SARS-CoV-2 variants. Antibody sd1.040 binds to subdomain 1, synergizes with antibody rbd.042 for neutralization, and, similar to fp.006 and hr2.016, protects mice expressing human angiotensin-converting enzyme 2 against infection when present as a bispecific antibody. Thus, coldspot-guided antibody discovery reveals donor-derived neutralizing antibodies that are cross-reactive with Orthocoronavirinae, including SARS-CoV-2 variants.

• MeSH
• COVID-19 * MeSH
• epitopy MeSH
• glykoprotein S, koronavirus MeSH
• lidé MeSH
• myši MeSH
• neutralizační testy MeSH
• neutralizující protilátky * MeSH
• protilátky virové MeSH
• SARS-CoV-2 MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Tick-borne encephalitis virus (TBEV) is an emerging human pathogen that causes potentially fatal disease with no specific treatment. Mouse monoclonal antibodies are protective against TBEV, but little is known about the human antibody response to infection. Here, we report on the human neutralizing antibody response to TBEV in a cohort of infected and vaccinated individuals. Expanded clones of memory B cells expressed closely related anti-envelope domain III (EDIII) antibodies in both groups of volunteers. However, the most potent neutralizing antibodies, with IC50s below 1 ng/ml, were found only in individuals who recovered from natural infection. These antibodies also neutralized other tick-borne flaviviruses, including Langat, louping ill, Omsk hemorrhagic fever, Kyasanur forest disease, and Powassan viruses. Structural analysis revealed a conserved epitope near the lateral ridge of EDIII adjoining the EDI-EDIII hinge region. Prophylactic or early therapeutic antibody administration was effective at low doses in mice that were lethally infected with TBEV.

• MeSH
• analýza přežití MeSH
• epitopy imunologie   MeSH
• imunoglobulin G aplikace a dávkování   imunologie   MeSH
• klíšťová encefalitida imunologie   prevence a kontrola   virologie   MeSH
• kohortové studie MeSH
• kultivované buňky MeSH
• lidé MeSH
• monoklonální protilátky aplikace a dávkování   genetika   imunologie   MeSH
• myši inbrední BALB C MeSH
• neutralizující protilátky aplikace a dávkování   genetika   imunologie   MeSH
• proteiny virového obalu genetika   imunologie   MeSH
• protilátky virové aplikace a dávkování   genetika   imunologie   MeSH
• sekvence aminokyselin MeSH
• sekvenční homologie aminokyselin MeSH
• viry klíšťové encefalitidy účinky léků   imunologie   fyziologie   MeSH
• zkřížené reakce imunologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH