Antibody Response against SARS-CoV-2 Infection: Implications for Diagnosis, Treatment and Vaccine Development

ABSTRACT Outer surface protein C (OspC) of the Lyme disease spirochetes is an important virulence factor that has potential utility for vaccine development. Of the 21 OspC types that have been identified, it has been postulated that types A, B, I, and K are specifically associated with invasive infections. Through an analysis of isolates collected from patients in Maryland we found that OspC types C, D, and N are also associated with invasive infections. This observation suggests that there is greater diversity in the group of OspC types associated with invasive infection than has been previously suggested. Detailed knowledge of the antigenic structure of OspC is essential for vaccine development. To determine if the antibody response to OspC is type specific, recombinant proteins of several different OspC types were immunoblotted and screened with sera from mice infected with isolates having known OspC types. These analyses revealed a high degree of specificity in the antibody response and suggested that the immunodominant epitopes of OspC reside in the variable domains of the protein. To localize these epitopes, OspC fragments were generated and screened with serum collected from infected mice. These analyses led to identification of previously uncharacterized epitopes that define the type specificity of the OspC antibody response. These analyses provide important insight into the antigenic structure of OspC and also provide a basis for understanding the variable nature of the antibody response to this important virulence factor of the Lyme disease spirochetes.

Download Full-text

Characterization of the Immune Response of MERS-CoV Vaccine Candidates Derived from Two Different Vectors in Mice

Viruses ◽

10.3390/v12010125 ◽

2020 ◽

Vol 12 (1) ◽

pp. 125 ◽

Cited By ~ 7

Author(s):

Entao Li ◽

Feihu Yan ◽

Pei Huang ◽

Hang Chi ◽

Shengnan Xu ◽

...

Keyword(s):

Immune Responses ◽

Antibody Response ◽

Rabies Virus ◽

Vaccine Development ◽

Vaccine Candidate ◽

Viral Vector ◽

Vaccine Vector ◽

Vaccine Candidates ◽

Cellular Immune Responses ◽

Cellular Immune

Middle East respiratory syndrome (MERS) is an acute, high-mortality-rate, severe infectious disease caused by an emerging MERS coronavirus (MERS-CoV) that causes severe respiratory diseases. The continuous spread and great pandemic potential of MERS-CoV make it necessarily important to develop effective vaccines. We previously demonstrated that the application of Gram-positive enhancer matrix (GEM) particles as a bacterial vector displaying the MERS-CoV receptor-binding domain (RBD) is a very promising MERS vaccine candidate that is capable of producing potential neutralization antibodies. We have also used the rabies virus (RV) as a viral vector to design a recombinant vaccine by expressing the MERS-CoV S1 (spike) protein on the surface of the RV. In this study, we compared the immunological efficacy of the vaccine candidates in BALB/c mice in terms of the levels of humoral and cellular immune responses. The results show that the rabies virus vector-based vaccine can induce remarkably earlier antibody response and higher levels of cellular immunity than the GEM particles vector. However, the GEM particles vector-based vaccine candidate can induce remarkably higher antibody response, even at a very low dose of 1 µg. These results indicate that vaccines constructed using different vaccine vector platforms for the same pathogen have different rates and trends in humoral and cellular immune responses in the same animal model. This discovery not only provides more alternative vaccine development platforms for MERS-CoV vaccine development, but also provides a theoretical basis for our future selection of vaccine vector platforms for other specific pathogens.

Download Full-text

Dense Bodies of a gH/gL/UL128/UL130/UL131 Pentamer-Repaired Towne Strain of Human Cytomegalovirus Induce an Enhanced Neutralizing Antibody Response

Journal of Virology ◽

10.1128/jvi.00931-19 ◽

2019 ◽

Vol 93 (17) ◽

Cited By ~ 6

Author(s):

Caroline Lehmann ◽

Jessica Julia Falk ◽

Nicole Büscher ◽

Inessa Penner ◽

Christine Zimmermann ◽

...

Keyword(s):

Endothelial Cells ◽

Antibody Response ◽

Human Cytomegalovirus ◽

Protein Complex ◽

Vaccine Development ◽

Laboratory Strain ◽

Neutralizing Antibody ◽

Critical Question ◽

Dense Bodies ◽

The Impact

ABSTRACTThe development of a vaccine against human cytomegalovirus infection (HCMV) is a high-priority medical goal. The viral pentameric protein complex consisting of glycoprotein H (gH)/gL/UL128-131A (PC) is considered to be an important vaccine component. Its relevance to the induction of a protective antibody response is, however, still a matter of debate. We addressed this issue by using subviral dense bodies (DBs) of HCMV. DBs are exceptionally immunogenic. Laboratory HCMV strain DBs harbor important neutralizing antibody targets, like the glycoproteins B, H, L, M, and N, but they are devoid of the PC. To be able to directly compare the impact of the PC on the levels of neutralizing antibody (NT-abs) responses, a PC-positive variant of the HCMV laboratory strain Towne was established by bacterial artificial chromosome (BAC) mutagenesis (Towne-UL130rep). This strain synthesized PC-positive DBs upon infection of fibroblasts. These DBs were used in side-by-side immunizations with PC-negative Towne DBs. Mouse and rabbit sera were tested to address the impact of the PC on DB immunogenicity. The neutralizing antibody response to PC-positive DBs was superior to that of PC-negative DBs, as tested on fibroblasts, epithelial cells, and endothelial cells and for both animal species used. The experiments revealed the potential of the PC to enhance the antibody response against HCMV. Of particular interest was the finding that PC-positive DBs induced an antibody response that blocked the infection of fibroblasts by a PC-positive viral strain more efficiently than sera following immunizations with PC-negative particles.IMPORTANCEInfections with the human cytomegalovirus (HCMV) may cause severe and even life-threatening disease manifestations in newborns and immunosuppressed individuals. Several strategies for the development of a vaccine against this virus are currently pursued. A critical question in this respect refers to the antigenic composition of a successful vaccine. Using a subviral particle vaccine candidate, we show here that one protein complex of HCMV, termed the pentameric complex (PC), enhances the neutralizing antibody response against viral infection of different cell types. We further show for the first time that this not only relates to the infection of epithelial or endothelial cells; the presence of the PC in the particles also enhanced the neutralizing antibody response against the infection of fibroblasts by HCMV. Together, these findings argue in favor of including the PC in strategies for HCMV vaccine development.

Download Full-text

Comparative Immunogenicity of Subtype A Human Immunodeficiency Virus Type 1 Envelope Exhibiting Differential Exposure of Conserved Neutralization Epitopes

Journal of Virology ◽

10.1128/jvi.01687-09 ◽

2009 ◽

Vol 84 (5) ◽

pp. 2573-2584 ◽

Cited By ~ 18

Author(s):

Catherine A. Blish ◽

D. Noah Sather ◽

George Sellhorn ◽

Leonidas Stamatatos ◽

Yide Sun ◽

...

Keyword(s):

Antibody Response ◽

Neutralizing Antibodies ◽

Vaccine Development ◽

Neutralizing Antibody ◽

Immunodeficiency Virus ◽

Cd4 Binding Site ◽

Variable Loops ◽

Linear Epitopes ◽

Subtype A ◽

Hiv 1

ABSTRACT Development of broadly cross-reactive neutralizing antibodies (NAbs) remains a major goal of HIV-1 vaccine development, but most candidate envelope immunogens have had limited ability to cross-neutralize heterologous strains. To evaluate the immunogenicity of subtype A variants of HIV-1, rabbits were immunized with pairs of closely related subtype A envelopes from the same individual. In each immunogen pair, one variant was readily neutralized by a variety of monoclonal antibodies and plasma antibodies, while the other was neutralization resistant, suggesting differences in the exposures of key epitopes. The breadth of the antibody response was evaluated against subtype A, B, C, and D variants of HIV-1. The specificity of the immunogen-derived neutralizing antibody response was also compared to that of the infected individuals from whom these variants were cloned. None of the immunogens produced broad neutralizing antibodies in immunized animals, and most of the neutralizing antibodies were directed to the variable loops, particularly the V3 loop. No detectable antibodies to either of the potentially exposed conserved epitopes, the membrane proximal external region, or the CD4 binding site were found with immunized rabbits. In contrast, relatively little of the neutralizing activity within the plasma samples of the infected individuals was directed to linear epitopes within the variable loops. These data indicate that immunogens designed to expose conserved regions did not enhance generation of broadly neutralizing antibodies in comparison with the immunogens that failed to expose those regions using this immunization approach.

Download Full-text

Evidence of antigenic imprinting in sequential Sarbecovirus immunization

10.1101/2020.10.14.339465 ◽

2020 ◽

Author(s):

Huibin Lv ◽

Ray T. Y. So ◽

Meng Yuan ◽

Hejun Liu ◽

Chang-Chun D. Lee ◽

...

Keyword(s):

Antibody Response ◽

Neutralizing Antibodies ◽

Vaccine Development ◽

Vaccination Strategy ◽

Vaccine Effectiveness ◽

Major Focus ◽

The World ◽

The One ◽

The Impact

SUMMARYAntigenic imprinting, which describes the bias of antibody response due to previous immune history, can influence vaccine effectiveness and has been reported in different viruses. Give that COVID-19 vaccine development is currently a major focus of the world, there is a lack of understanding of how background immunity influence antibody response to SARS-CoV-2. This study provides evidence for antigenic imprinting in Sarbecovirus, which is the subgenus that SARS-CoV-2 belongs to. Specifically, we sequentially immunized mice with two antigenically distinct Sarbecovirus strains, namely SARS-CoV and SARS-CoV-2. We found that the neutralizing antibodies triggered by the sequentially immunization are dominantly against the one that is used for priming. Given that the impact of the background immunity on COVID-19 is still unclear, our results will provide important insights into the pathogenesis of this disease as well as COVID-19 vaccination strategy.

Download Full-text

Proteoforms of the SARS-CoV-2 nucleocapsid protein are primed to proliferate the virus and attenuate the antibody response

10.1101/2020.10.06.328112 ◽

2020 ◽

Author(s):

Corinne A. Lutomski ◽

Tarick J. El-Baba ◽

Jani R. Bolla ◽

Carol V. Robinson

Keyword(s):

Antibody Response ◽

Nucleocapsid Protein ◽

Electron Transfer Dissociation ◽

Rna Binding ◽

Vaccine Development ◽

Cyclophilin A ◽

Proteolytic Processing ◽

Full Length ◽

Oligomeric State ◽

N Protein

AbstractThe SARS-CoV-2 nucleocapsid (N) protein is the most immunogenic of the structural proteins and plays essential roles in several stages of the virus lifecycle. It is comprised of two major structural domains: the RNA binding domain, which interacts with viral and host RNA, and the oligomerization domain which assembles to form the viral core. Here, we investigate the assembly state and RNA binding properties of the full-length nucleocapsid protein using native mass spectrometry. We find that dimers, and not monomers, of full-length N protein bind RNA, implying that dimers are the functional unit of ribonucleoprotein assembly. In addition, we find that N protein binds RNA with a preference for GGG motifs which are known to form short stem loop structures. Unexpectedly, we found that N undergoes proteolytic processing within the linker region, separating the two major domains. This process results in the formation of at least five proteoforms that we sequenced using electron transfer dissociation, higher-energy collision induced dissociation and corroborated by peptide mapping. The cleavage sites identified are in highly conserved regions leading us to consider the potential roles of the resulting proteoforms. We found that monomers of N-terminal proteoforms bind RNA with the same preference for GGG motifs and that the oligomeric state of a C-terminal proteoform (N156-419) is sensitive to pH. We then tested interactions of the proteoforms with the immunophilin cyclophilin A, a key component in coronavirus replication. We found that N1-209 and N1-273 bind directly to cyclophilin A, an interaction that is abolished by the approved immunosuppressant drug cyclosporin A. In addition, we found the C-terminal proteoform N156-419 generated the highest antibody response in convalescent plasma from patients >6 months from initial COVID-19 diagnosis when compared to the other proteoforms. Overall, the different interactions of N proteoforms with RNA, cyclophilin A, and human antibodies have implications for viral proliferation and vaccine development.

Download Full-text

Antibody Response against SARS-CoV-2 and Seasonal Coronaviruses in Nonhospitalized COVID-19 Patients

mSphere ◽

10.1128/msphere.01145-20 ◽

2021 ◽

Vol 6 (1) ◽

Author(s):

Natalia Ruetalo ◽

Ramona Businger ◽

Karina Althaus ◽

Simon Fink ◽

Felix Ruoff ◽

...

Keyword(s):

Antibody Response ◽

Vaccine Development ◽

Neutralizing Antibody ◽

Cross Protection ◽

Antibody Dependent Enhancement ◽

Strong Interest

There is strong interest in the nature of the neutralizing antibody response against SARS-CoV-2 in infected individuals. For vaccine development, it is especially important which antibodies confer protection against SARS-CoV-2, if there is a phenomenon called antibody-dependent enhancement (ADE) of infection, and if there is cross-protection by antibodies directed against seasonal coronaviruses.

Download Full-text

The receptor binding domain of SARS-CoV-2 spike is the key target of neutralizing antibody in human polyclonal sera

10.1101/2020.08.21.261727 ◽

2020 ◽

Cited By ~ 2

Author(s):

Tara L. Steffen ◽

E. Taylor Stone ◽

Mariah Hassert ◽

Elizabeth Geerling ◽

Brian T. Grimberg ◽

...

Keyword(s):

Antibody Response ◽

Receptor Binding ◽

Neutralizing Antibodies ◽

Vaccine Development ◽

Natural Infection ◽

Neutralizing Antibody ◽

Binding Domain ◽

Antigenic Determinants ◽

Receptor Binding Domain ◽

Neutralization Capacity

AbstractNatural infection of SARS-CoV-2 in humans leads to the development of a strong neutralizing antibody response, however the immunodominant targets of the polyclonal neutralizing antibody response are still unknown. Here, we functionally define the role SARS-CoV-2 spike plays as a target of the human neutralizing antibody response. In this study, we identify the spike protein subunits that contain antigenic determinants and examine the neutralization capacity of polyclonal sera from a cohort of patients that tested qRT-PCR-positive for SARS-CoV-2. Using an ELISA format, we assessed binding of human sera to spike subunit 1 (S1), spike subunit 2 (S2) and the receptor binding domain (RBD) of spike. To functionally identify the key target of neutralizing antibody, we depleted sera of subunit-specific antibodies to determine the contribution of these individual subunits to the antigen-specific neutralizing antibody response. We show that epitopes within RBD are the target of a majority of the neutralizing antibodies in the human polyclonal antibody response. These data provide critical information for vaccine development and development of sensitive and specific serological testing.

Download Full-text

Magnitude and Kinetics of Anti–Severe Acute Respiratory Syndrome Coronavirus 2 Antibody Responses and Their Relationship to Disease Severity

Clinical Infectious Diseases ◽

10.1093/cid/ciaa979 ◽

2020 ◽

Cited By ~ 12

Author(s):

Kara L Lynch ◽

Jeffrey D Whitman ◽

Noreen P Lacanienta ◽

Erica W Beckerdite ◽

Shannon A Kastner ◽

...

Keyword(s):

Severe Acute Respiratory Syndrome ◽

Antibody Response ◽

Disease Severity ◽

Dynamic Range ◽

Vaccine Development ◽

High Sensitivity ◽

Immunoglobulin M ◽

Viral Neutralization ◽

Mild Disease ◽

Protein Receptor

Abstract Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can be detected indirectly by measuring the host immune response. For some viruses, antibody concentrations correlate with host protection and viral neutralization, but in rare cases, antiviral antibodies can promote disease progression. Elucidation of the kinetics and magnitude of the SARS-CoV-2 antibody response is essential to understand the pathogenesis of coronavirus disease 2019 (COVID-19) and identify potential therapeutic targets. Methods Sera (n = 533) from patients with real-time polymerase chain reaction–confirmed COVID-19 (n = 94 with acute infections and n = 59 convalescent patients) were tested using a high-throughput quantitative immunoglobulin M (IgM) and immunoglobulin G (IgG) assay that detects antibodies to the spike protein receptor binding domain and nucleocapsid protein. Individual and serial samples covered the time of initial diagnosis, during the disease course, and following recovery. We evaluated antibody kinetics and correlation between magnitude of the response and disease severity. Results Patterns of SARS-CoV-2 antibody production varied considerably. Among 52 patients with 3 or more serial specimens, 44 (84.6%) and 42 (80.8%) had observed IgM and IgG seroconversion at a median of 8 and 10 days, respectively. Compared to those with milder disease, peak measurements were significantly higher for patients admitted to the intensive care unit for all time intervals between 6 and 20 days for IgM, and all intervals after 5 days for IgG. Conclusions High-sensitivity assays with a robust dynamic range provide a comprehensive picture of host antibody response to SARS-CoV-2. IgM and IgG responses were significantly higher in patients with severe than mild disease. These differences may affect strategies for seroprevalence studies, therapeutics, and vaccine development.

Download Full-text

Characterization of Heat-Stable (STa) Toxoids of Enterotoxigenic Escherichia coli Fused to Double Mutant Heat-Labile Toxin Peptide in Inducing Neutralizing Anti-STa Antibodies

Infection and Immunity ◽

10.1128/iai.01394-13 ◽

2014 ◽

Vol 82 (5) ◽

pp. 1823-1832 ◽

Cited By ~ 35

Author(s):

Xiaosai Ruan ◽

Donald C. Robertson ◽

James P. Nataro ◽

John D. Clements ◽

Weiping Zhang

Keyword(s):

Escherichia Coli ◽

Antibody Response ◽

Neutralizing Antibodies ◽

Double Mutant ◽

Vaccine Development ◽

Enterotoxigenic Escherichia Coli ◽

Virulence Determinants ◽

Heat Stable ◽

Heat Labile ◽

Fusion Antigen

ABSTRACTA long-standing challenge in developing vaccines against enterotoxigenicEscherichia coli(ETEC), the most common bacteria causing diarrhea in children of developing countries and travelers to these countries, is to protect against heat-stable toxin type Ib (STa or hSTa). STa and heat-labile toxin (LT) are virulence determinants in ETEC diarrhea. LT antigens are often used in vaccine development, but STa has not been included because of its poor immunogenicity and potent toxicity. Toxic STa is not safe for vaccines, but only STa possessing toxicity is believed to be able to induce neutralizing antibodies. However, recent studies demonstrated that nontoxic STa derivatives (toxoids), after being fused to an LT protein, induced neutralizing antibodies and suggested that different STa toxoids fused to an LT protein might exhibit different STa antigenic propensity. In this study, we selected 14 STa toxoids from a mini-STa toxoid library based on toxicity reduction and reactivity to anti-native STa antibodies, and genetically fused each toxoid to a monomeric double mutant LT (dmLT) peptide for 14 STa-toxoid-dmLT toxoid fusions. These toxoid fusions were used to immunize mice and were characterized for induction of anti-STa antibody response. The results showed that different STa toxoids (in fusions) varied greatly in anti-STa antigenicity. Among them, STaN12S, STaN12T, and STaA14Hwere the top toxoids in inducing anti-STa antibodies.In vitroneutralization assays indicated that antibodies induced by the 3×STaN12S-dmLT fusion antigen exhibited the greatest neutralizing activity against STa toxin. These results suggested 3×STaN12S-dmLT is a preferred fusion antigen to induce an anti-STa antibody response and provided long-awaited information for effective ETEC vaccine development.

Download Full-text