Systematic analysis of human antibody response to ebolavirus glycoprotein reveals high prevalence of neutralizing public clonotypes

Understanding the human antibody response to emerging viral pathogens is key to epidemic preparedness. As the size of the B cell response to a pathogenic virus protective antigen is undefined, we performed deep paired heavy and light chain sequencing in EBOV-GP specific memory B cells, allowing analysis of the ebolavirus-specific antibody repertoire both genetically and functionally. This approach facilitated investigation of the molecular and genetic basis for evolution of cross-reactive antibodies by elucidating germline-encoded properties of antibodies to EBOV and identification of the overlap between antibodies in the memory B-cell and serum repertoire. We identified 73 public clonotypes to EBOV, 20% of which encoded antibodies with neutralization activity and capacity to protect in vivo. This comprehensive analysis of the public and private antibody repertoire provides insight into the molecular basis of the humoral immune response to EBOV-GP, which informs vaccine design of new vaccines and improved therapeutics.

Antibodies elicited by SARS-CoV-2 infection or mRNA vaccines have reduced neutralizing activity against Beta and Omicron pseudoviruses

Multiple severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants that possess mutations associated with increased transmission and antibody escape have arisen over the course of the current pandemic. Although the current vaccines have largely been effective against past variants, the number of mutations found on the Omicron (B.1.1.529) spike protein appear to diminish the protection conferred by pre-existing immunity. Using vesicular stomatitis virus (VSV) pseudoparticles expressing the spike protein of several SARS-CoV-2 variants, we evaluated the magnitude and breadth of the neutralizing antibody response over time in individuals after infection and in mRNA-vaccinated individuals. We observed that boosting increases the magnitude of the antibody response to wildtype (D614), Beta, Delta, and Omicron variants; however, the Omicron variant was the most resistant to neutralization. We further observed that vaccinated healthy adults had robust and broad antibody responses whereas responses may have been reduced in vaccinated pregnant women, underscoring the importance of learning how to maximize mRNA vaccine responses in pregnant populations. Findings from this study show substantial heterogeneity in the magnitude and breadth of responses after infection and mRNA vaccination and may support the addition of more conserved viral antigens to existing SARS-CoV-2 vaccines.

The antibody response of haematological malignancies to COVID-19 infection and vaccination

SummaryCancer patients with COVID-19 have reduced survival. While most cancer patients, like the general population, have an almost 100% rate of seroconversion after COVID-19 infection or vaccination, patients with haematological malignancies have lower seroconversion rates and are far less likely to gain adequate protection. This raises the concern that patients with haematological malignancies, especially those receiving immunosuppressive therapies, may still develop the fatal disease when infected with COVID-19 after vaccination. There is an urgent need to develop Guidelines to help direct vaccination schedules and protective measures in oncology patients, differentiating those with haematological malignancies and those in an immunocompromised state.

Anti-PEG antibodies boosted in humans by SARS-CoV-2 lipid nanoparticle mRNA vaccine

Humans commonly have low level antibodies to poly(ethylene) glycol (PEG) due to environmental exposure. Lipid nanoparticle mRNA vaccines for SARS-CoV-2 contain small amounts of PEG but it is not known if PEG antibodies are enhanced by vaccination and if there are any consequences. We studied plasma from 55 people receiving the Comirnaty (Pfizer-BioNTech) mRNA vaccine for PEG-specific antibodies. Anti-PEG IgG was commonly detected prior to vaccination and was boosted a mean of 1.78-fold (range 0.68 to 16.6) by vaccination. Anti-PEG IgM increased 2.64-fold (0.76 to 12.84) following vaccination. PEG antibodies did not impact the neutralizing antibody response to vaccination. Pre-existing levels of anti-PEG IgM correlated with increased reactogenicity. A rise in PEG antibodies following vaccination was associated with an increase in the association of PEG-based nanoparticles to blood immune cells ex vivo. We conclude that low level PEG-specific antibodies can be modestly boosted by a lipid nanoparticle mRNA-vaccine and that PEG-specific antibodies are associated with higher reactogenicity. The longer-term clinical impact of the increase in PEG-specific antibodies induced by lipid nanoparticle mRNA-vaccines should be monitored.