B Cell Repertoire Analysis Identifies New Antigenic Domains on Glycoprotein B of Human Cytomegalovirus which Are Target of Neutralizing Antibodies

PLoS Pathogens

Luis Martin-Parras¹  Heinrich Sticht²  Pia Rücker²  Thomas Stamminger³  Anna-Katharina Wiegers³  Michael Mach³  Nadja Spindler³  Nina Grieb⁴  Florian Weisel⁴  Tanja Fisch⁴  Sonja Pötzsch⁴  Thomas H. Winkler⁴  Tina Baroti⁴ 

[1] 4-Antibody AG, Jena, Germany;Institut für Biochemie, Friedrich-Alexander Universität Erlangen-Nürnberg, Germany;Institut für Klinische und Molekulare Virologie Friedrich-Alexander Universität Erlangen-Nürnberg, Germany;Nikolaus-Fiebiger-Zentrum für Molekulare Medizin Friedrich-Alexander Universität Erlangen-Nürnberg, Germany

关键词: Antibodies;    Enzyme-linked immunoassays;    Protein domains;    Human cytomegalovirus;    B cells;    Cytomegalovirus infection;    Memory B cells;    Antigens;   

DOI  :  10.1371/journal.ppat.1002172

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Human cytomegalovirus (HCMV), a herpesvirus, is a ubiquitously distributed pathogen that causes severe disease in immunosuppressed patients and infected newborns. Efforts are underway to prepare effective subunit vaccines and therapies including antiviral antibodies. However, current vaccine efforts are hampered by the lack of information on protective immune responses against HCMV. Characterizing the B-cell response in healthy infected individuals could aid in the design of optimal vaccines and therapeutic antibodies. To address this problem, we determined, for the first time, the B-cell repertoire against glycoprotein B (gB) of HCMV in different healthy HCMV seropositive individuals in an unbiased fashion. HCMV gB represents a dominant viral antigenic determinant for induction of neutralizing antibodies during infection and is also a component in several experimental HCMV vaccines currently being tested in humans. Our findings have revealed that the vast majority (>90%) of gB-specific antibodies secreted from B-cell clones do not have virus neutralizing activity. Most neutralizing antibodies were found to bind to epitopes not located within the previously characterized antigenic domains (AD) of gB. To map the target structures of these neutralizing antibodies, we generated a 3D model of HCMV gB and used it to identify surface exposed protein domains. Two protein domains were found to be targeted by the majority of neutralizing antibodies. Domain I, located between amino acids (aa) 133–343 of gB and domain II, a discontinuous domain, built from residues 121–132 and 344–438. Analysis of a larger panel of human sera from HCMV seropositive individuals revealed positivity rates of >50% against domain I and >90% against domain II, respectively. In accordance with previous nomenclature the domains were designated AD-4 (Dom II) and AD-5 (Dom I), respectively. Collectively, these data will contribute to optimal vaccine design and development of antibodies effective in passive immunization.

【 授权许可】

CC BY