Enhanced immunity against SARS-CoV-2 in returning Chinese individuals

Global COVID-19 vaccination programs effectively contained the fast spread of SARS-CoV-2. Characterizing the immunity status of returned populations will favor understanding the achievement of herd immunity and long-term management of COVID-19 in China. Individuals were recruited from 7 quarantine stations in Guangzhou, China. Blood and throat swab specimens were collected from participants, and their immunity status was determined through competitive ELISA, microneutralization assay and enzyme-linked FluoroSpot assay. A total of 272 subjects were involved in the questionnaire survey, of whom 235 (86.4%) were returning Chinese individuals and 37 (13.6%) were foreigners. Blood and throat swab specimens were collected from 108 returning Chinese individuals. Neutralizing antibodies against SARS-CoV-2 were detected in ~90% of returning Chinese individuals, either in the primary or the homologous and heterologous booster vaccination group. The serum NAb titers were significantly decreased against SARS-CoV-2 Omicron BA.5, BF.7, BQ.1 and XBB.1 compared with the prototype virus. However, memory T-cell responses, including specific IFN-γ and IL-2 responses, were not different in either group. Smoking, alcohol consumption, SARS-CoV-2 infection, COVID-19 vaccination, and the time interval between last vaccination and sampling were independent influencing factors for NAb titers against prototype SARS-CoV-2 and variants of concern. The vaccine dose was the unique common influencing factor for Omicron subvariants. Enhanced immunity against SARS-CoV-2 was established in returning Chinese individuals who were exposed to reinfection and vaccination. Domestic residents will benefit from booster homologous or heterologous COVID-19 vaccination after reopening of China, which is also useful against breakthrough infection.

Immunogenicity and protective efficacy of inactivated coxsackievirus B4 viral particles

Coxsackievirus B4 (CVB4) is associated with a range of acute and chronic diseases such as hand, foot, and mouth disease, myocarditis, meningitis, pancreatitis, and type 1 diabetes, affecting millions of young children annually around the world. However, no vaccine is currently available for preventing CVB4 infection. Here, we report the development of inactivated viral particle vaccines for CVB4. Two types of inactivated CVB4 particles were prepared from CVB4-infected cell cultures as vaccine antigens, including F-particle (also called mature virion) consisting of VP1, VP3, VP2, and VP4 subunit proteins, and E-particle (also called empty capsid) which is made of VP1, VP3, and uncleaved VP0. Both the inactivated CVB4 F-particle and E-particle were able to potently elicit neutralizing antibodies in mice, despite slightly lower neutralizing antibody titres seen with the E-particle vaccine after the third immunization. Importantly, we demonstrated that passive transfer of either anti-F-particle or anti-E-particle sera could completely protect the recipient mice from lethal CVB4 challenge. Our study not only defines the immunogenicity and protective efficacy of inactivated CVB4 F-particle and E-particle but also reveals the central role of neutralizing antibodies in anti-CVB4 protective immunity, thus providing important information that may accelerate the development of inactivated CVB4 vaccines.

B cell characteristics define HCV reinfection outcome

BACKGROUND AND AIMS

In individuals highly exposed to hepatitis C virus (HCV), reinfection is common, suggesting that natural development of sterilising immunity is difficult. In those that are reinfected, some will develop a persistent infection, while a small proportion repeatedly clear the virus, suggesting natural protection is possible. The aim of this study was to characterise immune responses associated with rapid natural clearance of HCV reinfection.

METHODS

Broad neutralising antibodies (BnAbs) and Envelope 2 (E2)-specific memory B cell (MBCs) responses were examined longitudinally in 15 subjects with varied reinfection outcomes.

RESULTS

BnAb responses were associated with MBC recall, but not with reinfection clearance. Strong evidence of antigen imprinting was found, and the B cell receptor repertoire showed a high level of clonality with ongoing somatic hypermutation of many clones over subsequent reinfection events. Single cell transcriptomic analyses showed that cleared reinfections featured an activated transcriptomic profile in HCV-specific B cells that rapidly expanded upon reinfection.

CONCLUSIONS

MBC quality, but not necessarily breadth of nAb responses, is important for protection against antigenically diverse variants, which is encouraging for HCV vaccine development.

Distinct patterns of SARS-CoV-2 BA.2.87.1 and JN.1 variants in immune evasion, antigenicity, and cell-cell fusion

The rapid evolution of SARS-CoV-2 variants presents a constant challenge to the global vaccination effort. In this study, we conducted a comprehensive investigation into two newly emerged variants, BA.2.87.1 and JN.1, focusing on their neutralization resistance, infectivity, antigenicity, cell-cell fusion, and spike processing. Neutralizing antibody (nAb) titers were assessed in diverse cohorts, including individuals who received a bivalent mRNA vaccine booster, patients infected during the BA.2.86/JN.1-wave, and hamsters vaccinated with XBB.1.5-monovalent vaccine. We found that BA.2.87.1 shows much less nAb escape from WT-BA.4/5 bivalent mRNA vaccination and JN.1-wave breakthrough infection sera compared to JN.1 and XBB.1.5. Interestingly, BA.2.87.1 is more resistant to neutralization by XBB.1.5-monovalent-vaccinated hamster sera than BA.2.86/JN.1 and XBB.1.5, but efficiently neutralized by a class III monoclonal antibody S309, which largely fails to neutralize BA.2.86/JN.1. Importantly, BA.2.87.1 exhibits higher levels of infectivity, cell-cell fusion activity, and furin cleavage efficiency than BA.2.86/JN.1. Antigenically, we found that BA.2.87.1 is closer to the ancestral BA.2 compared to other recently emerged Omicron subvariants including BA.2.86/JN.1 and XBB.1.5. Altogether, these results highlight immune escape properties as well as biology of new variants and underscore the importance of continuous surveillance and informed decision-making in the development of effective vaccines.

IMPORTANCE

This study investigates the recently emerged SARS-CoV-2 variants, BA.2.87.1 and JN.1, in comparison to earlier variants and the parental D614G. Varied infectivity and cell-cell fusion activity among these variants suggest potential disparities in their ability to infect target cells and possibly pathogenesis. BA.2.87.1 exhibits lower nAb escape from bivalent mRNA vaccinee and BA.2.86/JN.1-infected sera than JN.1 but is relatively resistance to XBB.1.5-vaccinated hamster sera, revealing distinct properties in immune reason and underscoring the significance of continuing surveillance of variants and reformulation of vaccines. Antigenic differences between BA.2.87.1 and other earlier variants yield critical information not only for antibody evasion but also for viral evolution. In conclusion, this study furnishes timely insights into the spike biology and immune escape of the emerging variants BA.2.87.1 and JN.1, thus guiding effective vaccine development and informing public health interventions.

Unveiling the micronutrient-immunity puzzle in inactivated COVID-19 vaccination: A comprehensive analysis of circulating micronutrient levels and humoral responses in healthy adults

While micronutrients are crucial for immune function, their impact on humoral responses to inactivated COVID-19 vaccination remains unclear. We investigated the associations between seven key micronutrients and antibody responses in 44 healthy adults with two doses of an inactivated COVID-19 vaccine. Blood samples were collected pre-vaccination and 28 days post-booster. We measured circulating minerals (iron, zinc, copper, and selenium) and vitamins (A, D, and E) concentrations alongside antibody responses and assessed their associations using linear regression analyses. Our analysis revealed inverse associations between blood iron and zinc concentrations and anti-SARS-CoV-2 IgM antibody binding affinity (AUC for iron: β = -258.21, p < 0.0001; zinc: β = -17.25, p = 0.0004). Notably, antibody quality presented complex relationships. Blood selenium was positively associated (β = 18.61, p = 0.0030), while copper/selenium ratio was inversely associated (β = -1.36, p = 0.0055) with the neutralizing ability against SARS-CoV-2 virus at a 1:10 plasma dilution. There was no significant association between circulating micronutrient concentrations and anti-SARS-CoV-2 IgG binding affinity. These findings suggest that circulating iron, zinc, and selenium concentrations and copper/selenium ratio, may serve as potential biomarkers for both quantity (binding affinity) and quality (neutralization) of humoral responses after inactivated COVID-19 vaccination. Furthermore, they hint at the potential of pre-vaccination dietary interventions, such as selenium supplementation, to improve vaccine efficacy. However, larger, diverse studies are needed to validate these findings. This research advances the understanding of the impact of micronutrients on vaccine response, offering the potential for personalized vaccination strategies.

NS1: a promising novel target antigen with strong immunogenicity and protective efficacy for avian flavivirus vaccine development

Tembusu virus (TMUV), an avian pathogenic flavivirus, has emerged as a significant threat to the duck industry in Southeast Asia, causing substantial economic losses. Due to the antibody-dependent enhancement (ADE) effect of TMUV subneutralizing antibodies, there is a pressing need to further develop new TMUV vaccine target antigens that ensure both safety and efficacy. Here, the TMUV non-structural protein 1 (NS1) as a target for development of effective anti-TMUV vaccines was unveiled. The amino acid sequences of TMUV NS1 exhibit a high degree of conservation across different strains (92.63-100%). To investigate the potential of TMUV NS1 as a vaccine target, the TMUV NS1-based plasmids were constructed and identified the C-terminal 30 amino acids residues of TMUV E (EC30) as an effective signal peptide for promoting NS1 expression and secretion. Subsequently, the plasmid pVAX1-EC30-NS1 was employed to immunize ducks, resulting in specific anti-NS1 IgG responses being stimulated, while without inducing anti-TMUV neutralizing antibodies. Furthermore, the cellular immune responses triggered by the TMUV NS1 were evaluated, observing a notable increase in lymphocyte proliferation at 4 wk and 6 wk postinjection with the pVAX1-EC30-NS1. Additionally, there was a significant up-regulation of NS1-specific Il-4 and Ifnγ levels at these time points. Following this, ducks from different groups were challenged with TMUV, and remarkably, those immunized with the NS1 vaccine displayed significantly lower viral copies both at 3 d postinfection (dpi) and 7 dpi (P < 0.05) compared to ducks immunized with the control vector. Notably, the NS1 demonstrated remarkable protection against TMUV challenge without causing severe gross lesions. Collectively, these findings highlighted the impressive immunogenicity and protectivity of the TMUV NS1. Consequently, NS1 holds great promise as a novel antigen target for the development of efficient and safe TMUV vaccines.

Persistence of IgG and neutralizing antibodies in Crimean-Congo hemorrhagic fever survivors

The World Health Organization classified Crimean-Congo hemorrhagic fever (CCHF) as a high-priority infectious disease and emphasized the performance of research studies and product development against it. Little information is available about the immune response due to natural CCHF virus (CCHFV) infection in humans. Here, we investigated the persistence of IgG and neutralizing antibodies in serum samples collected from 61 Iranian CCHF survivors with various time points after recovery (<12, 12-60, and >60 months after disease). The ELISA results showed IgG seropositivity in all samples while a pseudotyped based neutralization assay findings revealed the presence of neutralizing antibody in 29 samples (46.77%). For both IgG and neutralizing antibodies, a decreasing trend of titer was observed with the increase in the time after recovery. Not only the mean titer of IgG (772.80 U/mL) was higher than mean neutralizing antibody (25.64) but also the IgG persistence was longer. In conclusion, our findings provide valuable information about the long-term persistence of humoral immune response in CCHF survivors indicating that IgG antibody can be detected at least 8 years after recovery and low titers of neutralizing antibody can be detected in CCHF survivors.

Neutralization of EG.5, EG.5.1, BA.2.86, and JN.1 by antisera from dimeric receptor-binding domain subunit vaccines and 41 human monoclonal antibodies

BACKGROUND

The recently circulating Omicron variants BA.2.86 and JN.1 were identified with more than 30 amino acid changes on the spike protein compared to BA.2 or XBB.1.5. This study aimed to comprehensively assess the immune escape potential of BA.2.86, JN.1, EG.5, and EG.5.1.

METHODS

We collected human and murine sera to evaluate serological neutralization activities. The participants received three doses of coronavirus disease 2019 (COVID-19) vaccines or a booster dose of the ZF2022-A vaccine (Delta-BA.5 receptor-binding domain [RBD]-heterodimer immunogen) or experienced a breakthrough infection (BTI). The ZF2202-A vaccine is under clinical trial study (ClinicalTrials.gov: NCT05850507). BALB/c mice were vaccinated with a panel of severe acute respiratory syndrome coronavirus 2 RBD-dimer proteins. The antibody evasion properties of these variants were analyzed with 41 representative human monoclonal antibodies targeting the eight RBD epitopes.

FINDINGS

We found that BA.2.86 had less neutralization evasion than EG.5 and EG.5.1 in humans. The ZF2202-A booster induced significantly higher neutralizing titers than BTI. Furthermore, BA.2.86 and JN.1 exhibited stronger antibody evasion than EG.5 and EG.5.1 on RBD-4 and RBD-5 epitopes. Compared to BA.2.86, JN.1 further lost the ability to bind to several RBD-1 monoclonal antibodies and displayed further immune escape.

CONCLUSIONS

Our data showed that the currently dominating sub-variant, JN.1, showed increased immune evasion compared to BA.2.86 and EG.5.1, which is highly concerning. This study provides a timely risk assessment of the interested sub-variants and the basis for updating COVID-19 vaccines.

FUNDING

This work was funded by the National Key R&D Program of China, the National Natural Science Foundation of China, the Beijing Life Science Academy, the Bill & Melinda Gates Foundation, and the Postdoctoral Fellowship Program of China Postdoctoral Science Foundation (CPSF).

A novel MARV glycoprotein-specific antibody with potentials of broad-spectrum neutralization to filovirus

Marburg virus (MARV) is one of the filovirus species that cause deadly hemorrhagic fever in humans, with mortality rates up to 90%. Neutralizing antibodies represent ideal candidates to prevent or treat virus disease. However, no antibody has been approved for MARV treatment to date. In this study, we identified a novel human antibody named AF-03 that targeted MARV glycoprotein (GP). AF-03 possessed a high binding affinity to MARV GP and showed neutralizing and protective activities against the pseudotyped MARV in vitro and in vivo. Epitope identification, including molecular docking and experiment-based analysis of mutated species, revealed that AF-03 recognized the Niemann-Pick C1 (NPC1) binding domain within GP1. Interestingly, we found the neutralizing activity of AF-03 to pseudotyped Ebola viruses (EBOV, SUDV, and BDBV) harboring cleaved GP instead of full-length GP. Furthermore, NPC2-fused AF-03 exhibited neutralizing activity to several filovirus species and EBOV mutants via binding to CI-MPR. In conclusion, this work demonstrates that AF-03 represents a promising therapeutic cargo for filovirus-caused disease.

Antibody level comparison after porcine epidemic diarrhea vaccination via different immunization routes

Porcine epidemic diarrhea (PED) is a disease extremely harmful to pig health. Intramuscular and Houhai acupoint injections are the main immunization routes to prevent and control PED. This study aimed to evaluate the efficacy of these two routes in pregnant sows based on serum IgG, IgA, and neutralizing antibody levels. PED virus (PEDV) immunoprophylaxis with live-attenuated and inactivated vaccines was administered. The vaccinations for the intramuscular injections elevated IgG and neutralizing antibody levels more than Houhai acupoint injections at most timepoints after immunization. However, the anti-PEDV IgA antibodies induced by vaccination with the two immunization routes did not differ significantly. In conclusion, intramuscular injections are better than Houhai acupoint injections for PEDV vaccination of pregnant sows.

TRAIL and IP-10 dynamics in pregnant women post COVID-19 vaccination: associations with neutralizing antibody potency

Introduction

The aim of this study is to investigate changes in TNF-related apoptosis-inducing ligand (TRAIL) and gamma interferon-induced protein 10 (IP-10) after COVID-19 vaccination in pregnant women and to explore their association with neutralizing antibody (Nab) inhibition.

Methods

The study evaluated 93 pregnant women who had previously received two (n=21), three (n=55) or four (n=17) doses of COVID-19 vaccine. Also we evaluated maternal blood samples that were collected during childbirth. The levels of TRAIL, IP-10 and Nab inhibition were measured using enzyme-linked immunosorbent assays (ELISA).

Results and discussion

Our study revealed four-dose group resulted in lower TRAIL levels when compared to the two-dose and three-dose groups (4.78 vs. 16.07 vs. 21.61 pg/ml, p = 0.014). The two-dose group had reduced IP-10 levels than the three-dose cohort (111.49 vs. 147.89 pg/ml, p=0.013), with no significant variation compared to the four-dose group. In addition, the four-dose group showed stronger Nab inhibition against specific strains (BA.2 and BA.5) than the three-dose group. A positive correlation was observed between TRAIL and IP-10 in the two-dose group, while this relationship was not found in other dose groups or between TRAIL/IP-10 and Nab inhibition. As the doses of the COVID-19 vaccine increase, the levels of TRAIL and IP-10 generally increase, only by the fourth dose, the group previously vaccinated with AZD1222 showed lower TRAIL but higher IP-10. Despite these changes, more doses of the vaccine consistently reinforced Nab inhibition, apparently without any relation to TRAIL and IP-10 levels. The variation may indicate the induction of immunological memory in vaccinated mothers, which justifies further research in the future.

Endogenous IL-27 during toxoplasmosis limits early monocyte responses and their inflammatory activation by pathological T cells

Mice that lack the genes for IL-27, or the IL-27 receptor, and infected with Toxoplasma gondii develop T cell-mediated pathology. Here, studies were performed to determine the impact of endogenous IL-27 on the immune response to T. gondii in wild-type (WT) mice. Analysis of infected mice revealed the early production of IL-27p28 by a subset of Ly6Chi, inflammatory monocytes, and sustained IL-27p28 production at sites of acute and chronic infection. Administration of anti-IL-27p28 prior to infection resulted in an early (day 5) increase in levels of macrophage and granulocyte activation, as well as enhanced effector T cell responses, as measured by both cellularity, cytokine production, and transcriptional profiling. This enhanced acute response led to immune pathology, while blockade during the chronic phase of infection resulted in enhanced T cell responses but no systemic pathology. In the absence of IL-27, the enhanced monocyte responses observed at day 10 were a secondary consequence of activated CD4+ T cells. Thus, in WT mice, IL-27 has distinct suppressive effects that impact innate and adaptive immunity during different phases of this infection.

IMPORTANCE

The molecule IL-27 is critical in limiting the immune response to the parasite Toxoplasma gondii. In the absence of IL-27, a lethal, overactive immune response develops during infection. However, when exactly in the course of infection this molecule is needed was unclear. By selectively inhibiting IL-27 during this parasitic infection, we discovered that IL-27 was only needed during, but not prior to, infection. Additionally, IL-27 is only needed in the active areas in which the parasite is replicating. Finally, our work found that a previously unstudied cell type, monocytes, was regulated by IL-27, which contributes further to our understanding of the regulatory networks established by this molecule.

Long-term analysis of humoral responses and spike-specific T cell memory to Omicron variants after different COVID-19 vaccine regimens

Background

The emergence of SARS-CoV-2 variants has raised concerns about the sustainability of vaccine-induced immunity. Little is known about the long-term humoral responses and spike-specific T cell memory to Omicron variants, with specific attention to BA.4/5, BQ.1.1, and XBB.1.

Methods

We assessed immune responses in 50 uninfected individuals who received varying three-dose vaccination combinations (2X AstraZeneca + 1X Moderna, 1X AstraZeneca + 2X Moderna, and 3X Moderna) against wild-type (WT) and Omicron variants at eight months post-vaccination. The serum antibody titers were analyzed by enzyme-linked immunosorbent assays (ELISA), and neutralizing activities were examined by pseudovirus and infectious SARS-CoV-2 neutralization assays. T cell reactivities and their memory phenotypes were determined by flow cytometry.

Results

We found that RBD-specific antibody titers, neutralizing activities, and CD4+ T cell reactivities were reduced against Omicron variants compared to WT. In contrast, CD8+ T cell responses, central memory, effector memory, and CD45RA+ effector memory T cells remained unaffected upon stimulation with the Omicron peptide pool. Notably, CD4+ effector memory T cells even exhibited a higher proportion of reactivity against Omicron variants. Furthermore, participants who received three doses of the Moderna showed a more robust response regarding neutralization and CD8+ T cell reactions than other three-dose vaccination groups.

Conclusion

Reduction of humoral and CD4+ T cell responses against Omicron variants in vaccinees suggested that vaccine effectiveness after eight months may not have sufficient protection against the new emerging variants, which provides valuable information for future vaccination strategies such as receiving BA.4/5 or XBB.1-based bivalent vaccines.

Neutralizing IgG4 antibodies are a biomarker of sustained efficacy after peanut oral immunotherapy

BACKGROUND

Clinical efficacy of oral immunotherapy (OIT) has been associated with the induction of blocking antibodies, particularly those capable of disrupting IgE-allergen interactions. Previously, we identified mAbs to Ara h 2 and structurally characterized their epitopes.

OBJECTIVE

We investigated longitudinal changes during OIT in antibody binding to conformational epitopes and correlated the results with isotype and clinical efficacy.

METHODS

We developed an indirect inhibitory ELISA using mAbs to block conformational epitopes on immobilized Ara h 2 from binding to serum immunoglobulins from peanut-allergic patients undergoing OIT. We tested the functional blocking ability of mAbs using passive cutaneous anaphylaxis in mice with humanized FcεRI receptors.

RESULTS

Diverse serum IgE recognition of Ara h 2 conformational epitopes are similar before and after OIT. Optimal inhibition of serum IgE occurs with the combination of 2 neutralizing mAbs (nAbs) recognizing epitopes 1.2 and 3, compared to 2 nonneutralizing mAbs (non-nAbs). After OIT, IgG4 nAbs, but not IgG1 or IgG2 nAbs, increased in sustained compared to transient outcomes. Induction of IgG4 nAbs occurs after OIT only in those with sustained efficacy. Murine passive cutaneous anaphylaxis after sensitization with pooled human sera is significantly inhibited by nAbs compared to non-nAbs.

CONCLUSIONS

Serum IgE conformational epitope diversity remains unchanged during OIT. However, IgG4 nAbs capable of uniquely disrupting IgE-allergen interactions to prevent effector cell activation are selectively induced in OIT-treated individuals with sustained clinical efficacy. Therefore, the induction of neutralizing IgG4 antibodies to Ara h 2 are clinically relevant biomarkers of durable efficacy in OIT.

Development of CNS tropic AAV1-like variants with reduced liver-targeting following systemic administration in mice

Directed evolution of natural AAV9 using peptide display libraries have been widely used in the search for an optimal recombinant AAV (rAAV) for transgene delivery across the blood-brain barrier (BBB) to the CNS following intravenous ( IV) injection. In this study, we used a different approach by creating a shuffled rAAV capsid library based on parental AAV serotypes 1 through 12. Following selection in mice, 3 novel variants closely related to AAV1, AAV-BBB6, AAV-BBB28, and AAV-BBB31, emerged as top candidates. In direct comparisons with AAV9, our novel variants demonstrated an over 270-fold improvement in CNS transduction and exhibited a clear bias toward neuronal cells. Intriguingly, our AAV-BBB variants relied on the LY6A cellular receptor for CNS entry, similar to AAV9 peptide variants AAV-PHP.eB and AAV.CAP-B10, despite the different bioengineering methods used and parental backgrounds. The variants also showed reduced transduction of both mouse liver and human primary hepatocytes in vivo. To increase clinical translatability, we enhanced the immune escape properties of our new variants by introducing additional modifications based on rational design. Overall, our study highlights the potential of AAV1-like vectors for efficient CNS transduction with reduced liver tropism, offering promising prospects for CNS gene therapies.

Chimeric oncolytic adenovirus evades neutralizing antibodies from human patients and exhibits enhanced anti-glioma efficacy in immunized mice

Oncolytic viruses are a promising treatment for patients with high-grade gliomas, but neutralizing antibodies can limit their efficacy in patients with prior virus exposure or upon repeated virus injections. Data from a previous clinical trial using the oncolytic adenovirus Delta-24-RGD showed that generation of anti-viral neutralizing antibodies may affect the long-term survival of glioma patients. Past studies have examined the effects of neutralizing antibodies during systemic virus injections, but largely overlooked their impact during local virus injections into the brain. We found that immunoglobulins colocalized with viral proteins upon local oncolytic virotherapy of brain tumors, warranting a strategy to prevent virus neutralization and maximize oncolysis. Thus, we generated a chimeric virus, Delta-24-RGD-H43m, by replacing the capsid protein HVRs from the serotype 5-based Delta-24-RGD with those from the rare serotype 43. Delta-24-RGD-H43m evaded neutralizing anti-Ad5 antibodies and conferred a higher rate of long-term survival than Delta-24-RGD in glioma-bearing mice. Importantly, Delta-24-RGD-H43m activity was significantly more resistant to neutralizing antibodies present in sera of glioma patients treated with Delta-24-RGD during a phase 1 clinical trial. These findings provide a framework for a novel treatment of glioma patients that have developed immunity against Delta-24-RGD.

Rapid isolation of pan-neutralizing antibodies against Omicron variants from convalescent individuals infected with SARS-CoV-2

Introduction

The emergence of SARS-CoV-2 Omicron subvariants has presented a significant challenge to global health, as these variants show resistance to most antibodies developed early in the pandemic. Therapeutic antibodies with potent efficacy to the Omicron variants are urgently demanded.

Methods

Utilizing the rapid antibody discovery platform, Berkeley Lights Beacon, we isolated two monoclonal neutralizing antibodies, 2173-A6 and 3462-A4. These antibodies were isolated from individuals who recently recovered from Omicron infections.

Results

Both antibodies, 2173-A6 and 3462-A4, demonstrated high affinity for the RBD and effectively neutralized pseudoviruses from various Omicron lineages, including BA.4/5, XBB.1.16, XBB.1.5, and EG.5.1. This neutralization was achieved through binding to identical or overlapping epitopes.

Discussion

The use of the Beacon platform enabled the rapid isolation and identification of effective neutralizing antibodies within less than 10 days. This process significantly accelerates the development of novel therapeutic antibodies, potentially reducing the time required to respond to unknown infectious diseases in the future.

Neutralizing antibody response to SARS-CoV-2 bivalent mRNA vaccine in SIV-infected rhesus macaques: Enhanced immunity to XBB subvariants by two-dose vaccination

The evolution of SARS-CoV-2 paired with immune imprinting by prototype messenger RNA (mRNA) vaccine has challenged the current vaccination efficacy against newly emerged Omicron subvariants. In our study, we investigated a cohort of macaques infected by SIV and vaccinated with two doses of bivalent Pfizer mRNA vaccine containing wildtype and BA.5 spikes. Using a pseudotyped lentivirus neutralization assay, we determined neutralizing antibody (nAb) titers against new XBB variants, i.e., XBB.1.5, XBB.1.16, and XBB.2.3, alongside D614G and BA.4/5. We found that compared to humans vaccinated with three doses of monovalent mRNA vaccine plus a bivalent booster, the monkeys vaccinated with two doses of bivalent mRNA vaccines exhibited relatively increased titers against XBB subvariants. Of note, SIV-positive dam macaques had reduced nAb titers relative to SIV-negative dams. Additionally, SIV positive dams that received antiretroviral therapy had lower nAb titers than untreated dams. Our study underscores the importance of reformulating the COVID-19 vaccine to better protect against newly emerged XBB subvariants as well as the need for further investigation of vaccine efficacy in individuals living with HIV-1.

Effector functions are required for broad and potent protection of neonatal mice with antibodies targeting HSV glycoprotein D

Multiple failed herpes simplex virus (HSV) vaccine candidates induce robust neutralizing antibody (Ab) responses in clinical trials, raising the hypothesis that Fc-domain-dependent effector functions may be critical for protection. While neonatal HSV (nHSV) infection results in mortality and lifelong neurological morbidity in humans, it is uncommon among neonates with a seropositive birthing parent, supporting the hypothesis that Ab-based therapeutics could protect neonates from HSV. We therefore investigated the mechanisms of monoclonal Ab (mAb)-mediated protection in a mouse model of nHSV infection. For a panel of glycoprotein D (gD)-specific mAbs, neutralization and effector functions contributed to nHSV-1 protection. In contrast, effector functions alone were sufficient to protect against nHSV-2, exposing a functional dichotomy between virus types consistent with vaccine trial results. Effector functions are therefore crucial for protection by these gD-specific mAbs, informing effective Ab and vaccine design and demonstrating the potential of polyfunctional Abs as therapeutics for nHSV infections.

Interim report of the reactogenicity and immunogenicity of SARS-CoV-2 XBB-containing vaccines

BACKGROUND

Monovalent Omicron XBB.1.5-containing vaccines were approved for Coronavirus disease 2019 (COVID-19) 2023-2024 immunizations.

METHODS

This ongoing, open-label, phase 2/3 study evaluated mRNA-1273.815-monovalent (50-µg Omicron XBB.1.5-spike mRNA) and mRNA-1273.231-bivalent (25-µg each Omicron XBB.1.5- and BA.4/BA.5-spike mRNAs))vaccines, administered as 5th doses to adults who previously received a primary series, a 3rd dose of an original mRNA COVID-19 vaccine, and a 4th dose of an Omicron BA.4/BA.5 bivalent vaccine. Interim safety and immunogenicity results 29 days post-vaccination are reported.

RESULTS

Participants (randomized 1:1) received 50-µg mRNA-1273.815(n=50) or mRNA-1273.231(n=51); median (interquartile range) months from the prior BA.4/BA.5-bivalent dose were 8.2 (8.1-8.3) and 8.3 (8.1-8.4), respectively. Neutralizing antibody (nAb) increased from pre-booster levels against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants tested. Day 29 nAb fold-increases from pre-booster levels were numerically higher against XBB.1.5, XBB.1.16, EG.5.1, BA.2.86, and JN.1 than BA.4/BA.5, BQ.1.1 and D614G. The monovalent vaccine also cross-neutralized FL.1.5.1, EG.5.1, BA.2.86, HK.3.1, HV.1 and JN.1 variants in a participant (n=20) subset, 15 days post-vaccination. Reactogenicity was similar to previously reported mRNA-1273 original and bivalent vaccines.

CONCLUSIONS

XBB.1.5-containing mRNA-1273 vaccines elicit robust, diverse nAb responses against more recent SARS-CoV-2 variants including JN.1, supporting the XBB.1.5-spike sequence selection for the 2023-2024 COVID-19 vaccine update.

Impact of Antenatal SARS-CoV-2 Exposure on SARS-CoV-2 Neutralization Potency

A pregnancy booster dose significantly reduces the risk and severity of COVID-19, and it is widely recommended. A prospective cohort study was conducted to compare the transplacental passage of maternal antibodies from vaccination or infection during three trimesters against both the vaccine-targeted Wuhan strain and the Omicron strain of SARS-CoV-2. Maternal-infant dyads from vaccinated mothers were collected between 6 June 2022 and 20 September 2022. We analyzed 38 maternal-infant dyads from mothers who had been infected with COVID-19 and 37 from mothers without any previous infection. Pregnant women who received their last COVID-19 vaccine dose in the third trimester exhibited the highest anti-spike protein antibody levels and neutralizing potency against both the Wuhan strain and Omicron BA.2 variant in their maternal and cord plasma. Both second- and third-trimester vaccination could lead to a higher level of neutralization against the Wuhan and Omicron strains. COVID-19 infection had a negative effect on the transplacental transfer ratio of SARS-CoV-2 antibodies. A booster dose during the second or third trimester is encouraged for the maximum transplacental transfer of humoral protection against COVID-19 for infants.

A SARS-CoV-2 RBD vaccine fused to the chemokine MIP-3α elicits sustained murine antibody responses over 12 months and enhanced lung T-cell responses

Background

Previous studies have demonstrated enhanced efficacy of vaccine formulations that incorporate the chemokine macrophage inflammatory protein 3α (MIP-3α) to direct vaccine antigens to immature dendritic cells. To address the reduction in vaccine efficacy associated with a mutation in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mutants, we have examined the ability of receptor-binding domain vaccines incorporating MIP-3α to sustain higher concentrations of antibody when administered intramuscularly (IM) and to more effectively elicit lung T-cell responses when administered intranasally (IN).

Methods

BALB/c mice aged 6-8 weeks were immunized intramuscularly or intranasally with DNA vaccine constructs consisting of the SARS-CoV-2 receptor-binding domain alone or fused to the chemokine MIP-3α. In a small-scale (n = 3/group) experiment, mice immunized IM with electroporation were followed up for serum antibody concentrations over a period of 1 year and for bronchoalveolar antibody levels at the termination of the study. Following IN immunization with unencapsulated plasmid DNA (n = 6/group), mice were evaluated at 11 weeks for serum antibody concentrations, quantities of T cells in the lungs, and IFN-γ- and TNF-α-expressing antigen-specific T cells in the lungs and spleen.

Results

At 12 months postprimary vaccination, recipients of the IM vaccine incorporating MIP-3α had significantly, approximately threefold, higher serum antibody concentrations than recipients of the vaccine not incorporating MIP-3α. The area-under-the-curve analyses of the 12-month observation interval demonstrated significantly greater antibody concentrations over time in recipients of the MIP-3α vaccine formulation. At 12 months postprimary immunization, only recipients of the fusion vaccine had concentrations of serum-neutralizing activity deemed to be effective. After intranasal immunization, only recipients of the MIP-3α vaccine formulations developed T-cell responses in the lungs significantly above those of PBS controls. Low levels of serum antibody responses were obtained following IN immunization.

Conclusion

Although requiring separate IM and IN immunizations for optimal immunization, incorporating MIP-3α in a SARS-CoV-2 vaccine construct demonstrated the potential of a stable and easily produced vaccine formulation to provide the extended antibody and T-cell responses that may be required for protection in the setting of emerging SARS-CoV-2 variants. Without electroporation, simple, uncoated plasmid DNA incorporating MIP-3α administered intranasally elicited lung T-cell responses.

Safety, Immunogenicity, and Mechanism of a Rotavirus mRNA-LNP Vaccine in Mice

Rotaviruses (RVs) are a major cause of diarrhea in young children worldwide. The currently available and licensed vaccines contain live attenuated RVs. Optimization of live attenuated RV vaccines or developing non-replicating RV (e.g., mRNA) vaccines is crucial for reducing the morbidity and mortality from RV infections. Herein, a nucleoside-modified mRNA vaccine encapsulated in lipid nanoparticles (LNP) and encoding the VP7 protein from the G1 type of RV was developed. The 5' untranslated region of an isolated human RV was utilized for the mRNA vaccine. After undergoing quality inspection, the VP7-mRNA vaccine was injected by subcutaneous or intramuscular routes into mice. Mice received three injections in 21 d intervals. IgG antibodies, neutralizing antibodies, cellular immunity, and gene expression from peripheral blood mononuclear cells were evaluated. Significant differences in levels of IgG antibodies were not observed in groups with adjuvant but were observed in groups without adjuvant. The vaccine without adjuvant induced the highest antibody titers after intramuscular injection. The vaccine elicited a potent antiviral immune response characterized by antiviral clusters of differentiation CD8+ T cells. VP7-mRNA induced interferon-γ secretion to mediate cellular immune responses. Chemokine-mediated signaling pathways and immune response were activated by VP7-mRNA vaccine injection. The mRNA LNP vaccine will require testing for protective efficacy, and it is an option for preventing rotavirus infection.

CXCL12 Neutralizing Antibody Promotes Hair Growth in Androgenic Alopecia and Alopecia Areata

We had previously investigated the expression and functional role of C-X-C Motif Chemokine Ligand 12 (CXCL12) during the hair cycle progression. CXCL12 was highly expressed in stromal cells such as dermal fibroblasts (DFs) and inhibition of CXCL12 increased hair growth. Therefore, we further investigated whether a CXCL12 neutralizing antibody (αCXCL12) is effective for androgenic alopecia (AGA) and alopecia areata (AA) and studied the underlying molecular mechanism for treating these diseases. In the AGA model, CXCL12 is highly expressed in DFs. Subcutaneous (s.c.) injection of αCXCL12 significantly induced hair growth in AGA mice, and treatment with αCXCL12 attenuated the androgen-induced hair damage in hair organ culture. Androgens increased the secretion of CXCL12 from DFs through the androgen receptor (AR). Secreted CXCL12 from DFs increased the expression of the AR and C-X-C Motif Chemokine Receptor 4 (CXCR4) in dermal papilla cells (DPCs), which induced hair loss in AGA. Likewise, CXCL12 expression is increased in AA mice, while s.c. injection of αCXCL12 significantly inhibited hair loss in AA mice and reduced the number of CD8+, MHC-I+, and MHC-II+ cells in the skin. In addition, injection of αCXCL12 also prevented the onset of AA and reduced the number of CD8+ cells. Interferon-γ (IFNγ) treatment increased the secretion of CXCL12 from DFs through the signal transducer and activator of transcription 3 (STAT3) pathway, and αCXCL12 treatment protected the hair follicle from IFNγ in hair organ culture. Collectively, these results indicate that CXCL12 is involved in the progression of AGA and AA and antibody therapy for CXCL12 is promising for hair loss treatment.

Long-Term Immunogenicity and Safety of a Homologous Third Dose Booster Vaccination with TURKOVAC: Phase 2 Clinical Study Findings with 32-Week Post-Booster Follow-Up

Vaccine-induced immunity wanes over time and warrants booster doses. We investigated the long-term (32 weeks) immunogenicity and safety of a third, homologous, open-label booster dose of TURKOVAC, administered 12 weeks after completion of the primary series in a randomized, controlled, double-blind, phase 2 study. Forty-two participants included in the analysis were evaluated for neutralizing antibodies (NAbs) (with microneutralization (MNT50) and focus reduction (FRNT50) tests), SARS-CoV-2 S1 RBD (Spike S1 Receptor Binding Domain), and whole SARS-CoV-2 (with ELISA) IgGs on the day of booster injection and at weeks 1, 2, 4, 8, 16, 24, and 32 thereafter. Antibody titers increased significantly from week 1 and remained higher than the pre-booster titers until at least week 4 (week 8 for whole SARS-CoV-2) (p < 0.05 for all). Seroconversion (titers ≥ 4-fold compared with pre-immune status) persisted 16 weeks (MNT50: 6-fold; FRNT50: 5.4-fold) for NAbs and 32 weeks for S1 RBD (7.9-fold) and whole SARS-CoV-2 (9.4-fold) IgGs. Nine participants (20.9%) tested positive for SARS-CoV-2 RT-PCR between weeks 8 and 32 of booster vaccination; none of them were hospitalized or died. These findings suggest that boosting with TURKOVAC can provide effective protection against COVID-19 for at least 8 weeks and reduce the severity of the disease.

Long-Term Kinetics of SARS-CoV-2 Neutralizing and Anti-Receptor Binding Domain Antibodies among Laboratory-Confirmed COVID-19 Cases in Delhi National Capital Region, India: A Prospective, One-Year Follow-Up Study

Background: This study was conducted with the objective of measuring the neutralizing and anti-receptor binding domain antibody levels against SARS-CoV-2 among laboratory-confirmed COVID-19 cases and exploring its long-term kinetics over a period of 1 year. Methods: One hundred laboratory-confirmed COVID-19 cases were recruited. Serum samples of the participants were collected within three months from the date of the positive COVID-19 report. The participants were prospectively followed up every three months for symptoms and the collection of blood samples for three additional rounds. The presence of anti-SARS-CoV-2 antibodies (IgA, IgG, and IgM antibodies), anti-receptor binding domain antibodies (anti-RBD), and neutralizing antibodies were measured. Findings: Median plaque reduction neutralization test (PRNT) titers showed a rising trend in the first three rounds of follow-up. The quantitative anti-receptor binding domain ELISA (QRBD) values showed a declining trend in the initial three rounds. However, both the PRNT titers and QRBD values showed significantly higher values for the fourth round of follow-up. Total antibody (WANTAI) levels showed an increasing trend in the initial three rounds (statistically significant). Interpretation: Neutralizing antibodies showed an increasing trend. The anti-receptor binding domain antibodies showed a decreasing trend. Neutralizing antibodies and anti-RBD antibodies persisted in the majority.

The Anti-SARS-CoV-2 IgG1 and IgG3 Antibody Isotypes with Limited Neutralizing Capacity against Omicron Elicited in a Latin Population a Switch toward IgG4 after Multiple Doses with the mRNA Pfizer-BioNTech Vaccine

The aim of this study was to analyze the profiles of IgG subclasses in COVID-19 convalescent Puerto Rican subjects and compare these profiles with those of non-infected immunocompetent or immunocompromised subjects that received two or more doses of an mRNA vaccine. The most notable findings from this study are as follows: (1) Convalescent subjects that were not hospitalized developed high and long-lasting antibody responses. (2) Both IgG1 and IgG3 subclasses were more prevalent in the SARS-CoV-2-infected population, whereas IgG1 was more prevalent after vaccination. (3) Individuals that were infected and then later received two doses of an mRNA vaccine exhibited a more robust neutralizing capacity against Omicron than those that were never infected and received two doses of an mRNA vaccine. (4) A class switch toward the "anti-inflammatory" antibody isotype IgG4 was induced a few weeks after the third dose, which peaked abruptly and remained at high levels for a long period. Moreover, the high levels of IgG4 were concurrent with high neutralizing percentages against various VOCs including Omicron. (5) Subjects with IBD also produced IgG4 antibodies after the third dose, although these antibody levels had a limited effect on the neutralizing capacity. Knowing that the mRNA vaccines do not prevent infections, the Omicron subvariants have been shown to be less pathogenic, and IgG4 levels have been associated with immunotolerance and numerous negative effects, the recommendations for the successive administration of booster vaccinations to people should be revised.

Identification of a broad sarbecovirus neutralizing antibody targeting a conserved epitope on the receptor-binding domain

Omicron, as the emerging variant with enhanced vaccine tolerance, has sharply disrupted most therapeutic antibodies. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) belongs to the subgenus Sarbecovirus, members of which share high sequence similarity. Herein, we report one sarbecovirus antibody, 5817, which has broad-spectrum neutralization capacity against SARS-CoV-2 variants of concern (VOCs) and SARS-CoV, as well as related bat and pangolin viruses. 5817 can hardly compete with six classes of receptor-binding-domain-targeted antibodies grouped by structural classifications. No obvious impairment in the potency is detected against SARS-CoV-2 Omicron and subvariants. The cryoelectron microscopy (cryo-EM) structure of neutralizing antibody 5817 in complex with Omicron spike reveals a highly conserved epitope, only existing at the receptor-binding domain (RBD) open state. Prophylactic and therapeutic administration of 5817 potently protects mice from SARS-CoV-2 Beta, Delta, Omicron, and SARS-CoV infection. This study reveals a highly conserved cryptic epitope targeted by a broad sarbecovirus neutralizing antibody, which would be beneficial to meet the potential threat of pre-emergent SARS-CoV-2 VOCs.

Long-lasting humoral and cellular memory immunity to vaccinia virus Tiantan provides pre-existing immunity against mpox virus in Chinese population

Investigating immune memory to vaccinia virus and pre-existing immunity to mpox virus (MPXV) among the population is crucial for the global response to this ongoing mpox epidemic. Blood was sampled from vaccinees inoculated with vaccinia virus Tiantan (VTT) strain born before 1981 and unvaccinated control subjects born since 1982. After at least 40 years of the inoculation, 60% or 5% VTT vaccinees possess neutralizing antibodies (NAbs) to VTT or MPXV, with at least 50% having T cell memory to VTT protein antigens. Notably, 46.7% vaccinees show pre-existing T cell responses to MPXV. Broad pre-existing CD8+ T cell reactivities to MPXV are detected not only against conserved epitopes but also against variant epitopes between VTT and MPXV. Persistent NAbs and T cell memory to VTT among vaccinees, along with pre-existing T cells to MPXV among both vaccinees and the unvaccinated population, indicate a particular immune barrier to mpox.

An omicron-specific neutralizing antibody test predicts neutralizing activity against XBB 1.5

Introduction

Understanding the immune status of an individual using neutralizing antibody testing is complicated by the continued evolution of the SARS-CoV-2 virus. Previous work showed that assays developed against the wildtype strain of SARS-CoV-2 were insufficient predictors of neutralization of omicron variants, thus we developed an omicron-specific flow cytometry-based neutralizing antibody test and performed experiments to assess how well it compared to an omicron-specific PRNT assay (gold standard) and whether it could predict neutralizing activity to more recent omicron subvariants such as XBB.1.5.

Methods

Accuracy of a novel flow cytometry-based neutralizing antibody (FC-NAb) assay was determined by comparison with an omicron-specific PRNT assay. A series of samples were evaluated in both the omicron FC-NAb assay and a second test was designed to assess neutralization of XBB.1.5.

Results

Good concordance between the omicron FC-NAb test and the omicron PRNT was demonstrated (AUC = 0.97, p <0.001; sensitivity = 94%, specificity = 100%, PPV = 100%, and NPV = 97%). A strong linear relationship between the omicron FC-NAb and neutralization of XBB1.5 was observed (r = 0.83, p<0.001). Additionally, the omicron FC-NAb test was a very strong predictor of positive XBB1.5 NAb activity (AUC = 0.96, p<0.001; sensitivity = 94%, specificity = 90%, positive predictive value = 90%, and negative predictive values = 94%).

Discussion

Our data suggest that despite continued evolution of the SARS-CoV-2 spike protein, the omicron FC-NAb assay described here is a good predictor of XBB1.5 neutralizing activity, as evidenced by a strong correlation and good predictive performance characteristics.

An in vitro experimental pipeline to characterize the epitope of a SARS-CoV-2 neutralizing antibody

IMPORTANCE

The COVID-19 pandemic remains a significant public health concern for the global population; the development and characterization of therapeutics, especially ones that are broadly effective, will continue to be essential as severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) variants emerge. Neutralizing monoclonal antibodies remain an effective therapeutic strategy to prevent virus infection and spread so long as they recognize and interact with circulating variants. The epitope and binding specificity of a neutralizing anti-SARS-CoV-2 Spike receptor-binding domain antibody clone against many SARS-CoV-2 variants of concern were characterized by generating antibody-resistant virions coupled with cryo-EM structural analysis and VSV-spike neutralization studies. This workflow can serve to predict the efficacy of antibody therapeutics against emerging variants and inform the design of therapeutics and vaccines.

Perineural Treatment with High Mobility Group Box-1 Monoclonal Antibody Prevents Initiation of Pain-Like Behaviors in Female Mice with Trigeminal Neuropathy

Post-traumatic trigeminal neuropathy (PTTN) is a type of chronic pain caused by damage to the trigeminal nerve. A previous study reported that pretreatment with anti-high mobility group box-1 (HMGB1) neutralizing antibodies (nAb) prevented the onset of PTTN following distal infraorbital nerve chronic constriction injury (dIoN-CCI) in male mice. Clinical evidence indicates a high incidence of PTTN in females. Although our previous study found that perineural HMGB1 is crucial in initiation of PTTN in male mice, it is currently unknown whether HMGB1 is also involved in the pathogenesis of PTTN in female mice. Therefore, in the current study, we examined the effect of anti-HMGB1 nAb on pain-like behavior in female mice following dIoN-CCI surgery. We found that dIoN-CCI surgery enhanced reactivity to mechanical and cold stimuli in female mice, which was suppressed by treatment with anti-HMGB1 nAb. Moreover, the increase in macrophages after dIoN-CCI was significantly attenuated by pretreatment with anti-HMGB1 nAb. Furthermore, anti-HMGB1 nAb treatment inhibited microglial activation in the trigeminal spinal tract nucleus. These data suggest that HMGB1 also plays a crucial role in the onset of PTTN after nerve injury in female mice. Thus, anti-HMGB1 nAb could be a novel therapeutic agent for inhibiting the onset of PTTN in female and male mice.

Therapeutic efficacy of a potent anti-Venezuelan equine encephalitis virus antibody is contingent on Fc effector function

The development of specific, safe, and potent monoclonal antibodies (Abs) has led to novel therapeutic options for infectious disease. In addition to preventing viral infection through neutralization, Abs can clear infected cells and induce immunomodulatory functions through engagement of their crystallizable fragment (Fc) with complement proteins and Fc receptors on immune cells. Little is known about the role of Fc effector functions of neutralizing Abs in the context of encephalitic alphavirus infection. To determine the role of Fc effector function in therapeutic efficacy against Venezuelan equine encephalitis virus (VEEV), we compared the potently neutralizing anti-VEEV human IgG F5 (hF5) Ab with intact Fc function (hF5-WT) or containing the loss of function Fc mutations L234A and L235A (hF5-LALA) in the context of VEEV infection. We observed significantly reduced binding to complement and Fc receptors, as well as differential in vitro kinetics of Fc-mediated cytotoxicity for hF5-LALA compared to hF5-WT. The in vivo efficacy of hF5-LALA was comparable to hF5-WT at -24 and + 24 h post infection, with both Abs providing high levels of protection. However, when hF5-WT and hF5-LALA were administered + 48 h post infection, there was a significant decrease in the therapeutic efficacy of hF5-LALA. Together these results demonstrate that optimal therapeutic Ab treatment of VEEV, and possibly other encephalitic alphaviruses, requires neutralization paired with engagement of immune effectors via the Fc region.

Further accelerating biologics development from DNA to IND: the journey from COVID-19 to non-COVID-19 programs

The Coronavirus Disease (COVID-19) pandemic has spurred adoption of revolutionary initiatives by regulatory agencies and pharmaceutical industry worldwide to deliver therapeutic COVID-19 antibodies to patients at unprecedented speed. Among these, timeline of chemistry, manufacturing and control (CMC), which involves process development and manufacturing activities critical for the assurance of product quality and consistency before first-in-human clinical trials, was greatly reduced from typically 12-15 months (using clonal materials) to approximately 3 months (using non-clonal materials) in multiple cases. In this perspective, we briefly review the acceleration approaches published for therapeutic COVID-19 antibodies and subsequently discuss the applicability of these approaches to achieve investigational new drug (IND) timelines of ≤10 months in over 60 COVID-19 and non-COVID-19 programs performed at WuXi Biologics. We are of the view that, with demonstrated product quality and consistency, innovative approaches used for COVID-19 can be widely applied in all disease areas for greater speed to clinic.

Unravelling heterogeneous effects of cancer‑associated fibroblasts on poor prognosis markers in breast cancer EM‑G3 cell line: In vitro‑targeted treatment (anti‑IL-6, anti‑VEGF-A, anti‑MFGE8) based on transcriptomic profiling

Breast cancer is the most frequently diagnosed cancer in women worldwide. Although dramatically increased survival rates of early diagnosed cases have been observed, late diagnosed patients and metastatic cancer may still be considered fatal. The present study's main focus was on cancer‑associated fibroblasts (CAFs) which is an active component of the tumor microenvironment (TME) regulating the breast cancer ecosystem. Transcriptomic profiling and analysis of CAFs isolated from breast cancer skin metastasis, cutaneous basal cell carcinoma, and squamous cell carcinoma unravelled major gene candidates such as IL6, VEGFA and MFGE8 that induced co‑expression of keratins‑8/‑14 in the EM‑G3 cell line derived from infiltrating ductal breast carcinoma. Western blot analysis of selected keratins (keratin‑8, ‑14, ‑18, ‑19) and epithelial‑mesenchymal transition‑associated markers (SLUG, SNAIL, ZEB1, E‑/N‑cadherin, vimentin) revealed specific responses pointing to certain heterogeneity of the studied CAF populations. Experimental in vitro treatment using neutralizing antibodies against IL-6, VEGF‑A and MFGE8 attenuated the modulatory effect of CAFs on EM‑G3 cells. The present study provided novel data in characterizing and understanding the interactions between CAFs and EM‑G3 cells in vitro. CAFs of different origins support the pro‑inflammatory microenvironment and influence the biology of breast cancer cells. This observation potentially holds significant interest for the development of novel, clinically relevant approaches targeting the TME in breast cancer. Furthermore, its implications extend beyond breast cancer and have the potential to impact a wide range of other cancer types.

Prevalence of Adeno-Associated Virus-9-Neutralizing Antibody in Chinese Patients with Duchenne Muscular Dystrophy

The delivery of a mini-dystrophin gene to skeletal muscles using recombinant adeno-associated virus serotype (AAV) holds great potential as a gene therapy for Duchenne muscular dystrophy (DMD). However, the presence of anti-AAV-neutralizing antibodies (NAbs) may impede the effectiveness of gene transduction. This study aimed to evaluate the prevalence of anti-AAV9 NAbs in Chinese patients with DMD, and to characterize the target population for an AAV gene therapy. A total of one hundred male patients with DMD were included in this study, and demographic and clinical data were collected. A blood specimen was obtained from each participant for the purpose of evaluating the existence of anti-AAV9 NAbs through a cell-based functional assay conducted at a central laboratory. A NAb titer exceeding 1:4 was considered positive. The positivity rates of anti-AAV9 NAb were compared among different subgroups. The median age of this DMD cohort was 8 years old, ranging from 3 to 15 years of age. Forty-two percent of patients tested positive for anti-AAV9 NAb. Notably, all samples from patients under 4 years of age tested negative, and the positivity rates of anti-AAV9 NAb differed significantly across the three age subgroups (<4 years old, ≥4 years old and <12 years old, and ≥12 years old, χ2 = 7.221, p = 0.023). Further investigation into the living environment revealed a higher positivity rate of anti-AAV9 NAb in rural patients compared with urban patients (χ2 = 3.923, p = 0.048). Moreover, the prevalence in patients from different cities/provinces varied greatly (χ2 = 16.550, p = 0.003). There was no statistically significant difference in the positivity rate of NAb among subgroups of patients with different motor functions (ambulatory or nonambulatory) and different treatment strategies (taking or not taking glucocorticoid). In Chinese DMD patients, the prevalence of anti-AAV9 NAb was found to reach 42%. Moreover, the antibody-positive rate in children <4 years of age was low and revealed notable regional discrepancies.

[Investigation of Chronic Pain for the Development of Novel Analgesics Focusing on High Mobility Group Box-1]

Neuropathic pain is an infirm type of chronic pain, which results in functional and emotional impairment. There is an urgent need for novel therapeutic approaches because there is lack of effective treatment for neuropathic pain. Posttraumatic trigeminal neuropathy (PTTN), a chronic sensory disorder following trauma, for example, during dental implant surgery or third molar removal, can cause orofacial numbness, paresthesia and pain. Unlike other painful peripheral neuropathies, the chance of developing PTTN is predictable based on preoperative assessment such as X-ray of the trigeminal nerve tract and the surgery site. High mobility group box-1 (HMGB1) acts as damage associated molecular patterns (DAMPs) and contributes to the pathogenesis of neuropathic pain including diabetic and chemotherapy-induced peripheral neuropathy. Recently, we have demonstrated that HMGB1 around injured sciatic nerves is a key molecule triggering the onset of neuropathic pain. We therefore hypothesize that inhibition of HMGB1 could prevent the onset of PTTN. In a mouse PTTN model, pretreatment with anti-HMGB1 neutralizing antibody can attenuate PTTN-induced behavioral painful responses and suppress microglial activation in spinal trigeminal nucleus caudalis. In summary, perioperative inhibition of HMGB1 activity could be used to prevent the onset of PTTN. This review summarizes recent findings regarding the role of HMGB1 in the induction of neuropathic pain and may generate new translational opportunities for pain treatment.

Safety and immunogenicity of homologous prime-boost CoronaVac vaccine in people living with HIV in China: A multicenter prospective cohort study

People living with HIV (PLWH) are particularly vulnerable to SARS-CoV-2. This multicentre prospective cohort study evaluated the long-term immunogenicity and safety of a third homologous dose of Sinovac CoronaVac in PLWH in China. A total of 228 PLWH and 127 HIV-negative controls were finally included and followed up for 6 months. Fewer participants reported mild or moderate adverse reactions, and no serious adverse events were observed. The median levels of neutralizing antibodies (nAbs) and immunoglobulin G against the receptor-binding domain of the spike protein (S-IgG) in PLWH (655.92 IU/mL, IQR: 175.76-1663.55; 206.83 IU/mL, IQR: 85.20-397.82) were comparable to those in control group (1067.16 IU/mL, IQR: 239.85-1670.83; 261.70 IU/mL, IQR: 77.13-400.75), and reached their peak at 4 weeks, exhibiting a delayed peak pattern compared to the 2-week peak in control group. After then, the immune titres gradually decreased over time, but most participants still maintained positive seroconversion at the 6-month mark. Multivariable generalized estimating equation analysis indicated that CD4+T cell count, HIV viral load, and antiretroviral therapy (ART) were independent factors strongly associated with immune response (each p < 0.05). We suggested that PLWH should maintain well-controlled HIV status through ART and receive timely administration of the second booster dose for optimal protection.

Immune escape of BA.2.86 is comparable to XBB subvariants from the plasma of BA.5- and BA.5-XBB-convalescent subpopulations

The EG.5.1 variant of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has been prevalent since mid-July 2023 in the United States and China. The variant BA.2.86 has become a major concern because it is 34 mutations away from the parental variant BA.2 and >30 mutations from XBB.1.5. There is an urgent need to evaluate whether the immunity of the population and current vaccines are protective against EG.5.1 and BA.2.86. Based on a cohort of two breakthrough-infected groups, the levels of neutralizing antibodies (NAbs) against different subvariants were measured using pseudovirus-based neutralization assays. XBB.1.5, EG.5.1, and BA.2.86 are comparably immune-evasive from neutralization by the plasma of individuals recovered from BA.5 infection (BA.5-convalescent) or XBB.1.9.2/XBB.1.5 infection following BA.5 infection (BA.5-XBB-convalescent). NAb levels against EG.5.1 and BA.2.86 subvariants remained >120 geometric mean titers (GMTs) in BA.5-XBB-convalescent individuals 2 months postinfection but were <40 GMTs in BA.5-convalescent individuals. Furthermore, the XBB-targeting messenger RNA (mRNA) vaccine RQ3033 induced higher levels of NAbs against XBB.1.5, EG.5.1, and BA.2.86 than against BA.5-XBB infection. The results suggest that BA.2.86 and EG.5.1 are unlikely to cause more severe concerns than the currently circulating XBB subvariants and that the XBB.1.5-targeting mRNA vaccine tested has promising protection against EG.5.1 and BA.2.86.

Establishment of the 1st Chinese national standard for CA6 neutralizing antibody

Coxsackievirus A6 (CA6) is one of the major causative agents of herpangina and hand-foot-mouth disease (HFMD). Since 2008, CA6 has circulated widely around the world. Especially in Asia-Pacific region CA6 had even replaced enterovirus A71 (EV71) and coxsackievirus A16 (CA16) as the main prevalent strain of HFMD. In the recent 10 years, monovalent and multivalent vaccines against CA6 have been researched and developed by manufacturers from China, Korea, and the USA. The neutralizing antibody titer is a key indicator for accurately evaluating immunogenicity of vaccine. However, so far, the World Health Organization international standard for CA6 neutralizing antibody has not been available. In order to meet the needs of evaluating the immunogenicity of vaccines against CA6, the first Chinese national standard for CA6 neutralizing antibody was established, which was conducted to ensure that methods used to measure the neutralizing antibody titers against CA6 are accurate, reliable, and comparable. Three lyophilized candidate standards (29#, 39# and 44#) were produced with 0.40 ml/vial from plasma samples donated by healthy individuals. The collaborative study showed that the 29# candidate standard could effectively minimize the variability in neutralization titers between labs and across challenging viruses of different genotypes (A, D1, and D3). Therefore, the 29# candidate sample was established as the first Chinese national standard for CA6 neutralizing antibody test. This standard has good long-term stability and was assigned a potency of 150 units per milliliter (U/ml) of CA6 neutralizing antibody. It will contribute to ensure uniformity of potency or activity of vaccines and potentially therapeutic antibody preparations.

Generation and Characterization of a Multi-Functional Panel of Monoclonal Antibodies for SARS-CoV-2 Research and Treatment

The Coronavirus disease 2019 (COVID-19) pandemic caused by Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) is an ongoing threat to global public health. To this end, intense efforts are underway to develop reagents to aid in diagnostics, enhance preventative measures, and provide therapeutics for managing COVID-19. The recent emergence of SARS-CoV-2 Omicron variants with enhanced transmissibility, altered antigenicity, and significant escape of existing monoclonal antibodies and vaccines underlines the importance of the continued development of such agents. The SARS-CoV-2 spike protein and its receptor binding domain (RBD) are critical to viral attachment and host cell entry and are primary targets for antibodies elicited from both vaccination and natural infection. In this study, mice were immunized with two synthetic peptides (Pep 1 and Pep 2) within the RBD of the original Wuhan SARS-CoV-2, as well as the whole RBD as a recombinant protein (rRBD). Hybridomas were generated, and a panel of three monoclonal antibodies, mAb CU-P1-1 against Pep 1, mAb CU-P2-20 against Pep 2, and mAb CU-28-24 against rRBD, was generated and further characterized. These mAbs were shown by ELISA to be specific for each immunogen/antigen. Monoclonal antibody CU-P1-1 has limited applicability other than in ELISA approaches and basic immunoblotting. Monoclonal antibody CU-P2-20 is shown to be favorable for ELISA, immunoblotting, and immunohistochemistry (IHC), however, not live virus neutralization. In contrast, mAb CU-28-24 is most effective at live virus neutralization as well as ELISA and IHC. Moreover, mAb CU-28-24 is active against rRBD proteins from Omicron variants BA.2 and BA.4.5 as determined by ELISA, suggesting this mAb may neutralize live virus of these variants. Each of the immunoglobulin genes has been sequenced using Next Generation Sequencing, which allows the expression of respective recombinant proteins, thereby eliminating the need for long-term hybridoma maintenance. The synthetic peptides and hybridomas/mAbs and quantitative antigen-binding data are under the intellectual property management of the Clemson University Research Foundation, and the three CDRs have been submitted as an invention disclosure for further patenting and commercialization.

Defining a de novo non-RBM antibody as RBD-8 and its synergistic rescue of immune-evaded antibodies to neutralize Omicron SARS-CoV-2

Currently, monoclonal antibodies (MAbs) targeting the SARS-CoV-2 receptor binding domain (RBD) of spike (S) protein are classified into seven classes based on their binding epitopes. However, most of these antibodies are seriously impaired by SARS-CoV-2 Omicron and its subvariants, especially the recent BQ.1.1, XBB and its derivatives. Identification of broadly neutralizing MAbs against currently circulating variants is imperative. In this study, we identified a "breathing" cryptic epitope in the S protein, named as RBD-8. Two human MAbs, BIOLS56 and IMCAS74, were isolated recognizing this epitope with broad neutralization abilities against tested sarbecoviruses, including SARS-CoV, pangolin-origin coronaviruses, and all the SARS-CoV-2 variants tested (Omicron BA.4/BA.5, BQ.1.1, and XBB subvariants). Searching through the literature, some more RBD-8 MAbs were defined. More importantly, BIOLS56 rescues the immune-evaded antibody, RBD-5 MAb IMCAS-L4.65, by making a bispecific MAb, to neutralize BQ.1 and BQ.1.1, thereby producing an MAb to cover all the currently circulating Omicron subvariants. Structural analysis reveals that the neutralization effect of RBD-8 antibodies depends on the extent of epitope exposure, which is affected by the angle of antibody binding and the number of up-RBDs induced by angiotensin-converting enzyme 2 binding. This cryptic epitope which recognizes non- receptor binding motif (non-RBM) provides guidance for the development of universal therapeutic antibodies and vaccines against COVID-19.

Neutralizing Antibody Response following a Third Dose of the mRNA-1273 Vaccine among Cancer Patients

Cancer patients are at an increased risk of morbidity and mortality from SARS-CoV-2 infection and have a decreased immune response to vaccination. We conducted a study measuring both the neutralizing and total antibodies in cancer patients following a third dose of the mRNA-1273 COVID-19 vaccine. Immune responses were measured with an enzyme-linked immunosorbent assay (ELISA) and neutralization assays. Kruskal-Wallis tests were used to evaluate the association between patient characteristics and neutralization geometric mean titers (GMTs), and paired t-tests were used to compare the GMTs between different timepoints. Spearman correlation coefficients were calculated to determine the correlation between total antibody and neutralization GMTs. Among 238 adults diagnosed with cancer, a third dose of mRNA-1273 resulted in a 37-fold increase in neutralization GMT 28 days post-vaccination and maintained a 14.6-fold increase at 6 months. Patients with solid tumors or lymphoid cancer had the highest and lowest neutralization GMTs, respectively, at both 28 days and 6 months post-dose 3. While total antibody GMTs in lymphoid patients continued to increase, other cancer types showed decreases in titers between 28 days and 6 months post-dose 3. A strong correlation (p < 0.001) was found between total antibody and neutralization GMTs. The third dose of mRNA-1273 was able to elicit a robust neutralizing antibody response in cancer patients, which remained for 6 months after administration. Lymphoid cancer patients can benefit most from this third dose, as it was shown to continue to increase total antibody GMTs 6 months after vaccination.

Structural characterization of M8C10, a neutralizing antibody targeting a highly conserved prefusion-specific epitope on the metapneumovirus fusion trimerization interface

IMPORTANCE

Human metapneumovirus (hMPV) is a common pathogen causing lower respiratory tract infections worldwide and can develop severe symptoms in high-risk populations such as infants, the elderly, and immunocompromised patients. There are no approved hMPV vaccines or neutralizing antibodies available for therapeutic or prophylactic use. The trimeric hMPV fusion F protein is the major target of neutralizing antibodies in human sera. Understanding the immune recognition of antibodies to hMPV-F antigen will provide critical insights into developing efficacious hMPV monoclonal antibodies and vaccines.

Preinfection Neutralizing Antibodies, Omicron BA.5 Breakthrough Infection, and Long COVID: A Propensity Score-Matched Analysis

BACKGROUND

Data are limited on the role of preinfection humoral immunity protection against Omicron BA.5 infection and long coronavirus disease (COVID) development.

METHODS

We conducted nested case-control analysis among tertiary hospital staff in Tokyo who donated blood samples in June 2022 (1 month before Omicron BA.5 wave), approximately 6 months after receiving a third dose of COVID-19 mRNA vaccine. We measured live virus-neutralizing antibody titers against wild type and Omicron BA.5, and anti-receptor-binding domain (RBD) antibody titers at preinfection, and compared them between cases and propensity-matched controls. Among the breakthrough cases, we examined association between preinfection antibody titers and incidence of long COVID.

RESULTS

Preinfection anti-RBD and neutralizing antibody titers were lower in cases than controls. Neutralizing titers against wild type and Omicron BA.5 were 64% (95% confidence interval [CI], 42%-77%) and 72% (95% CI, 53%-83%) lower, respectively, in cases than controls. Individuals with previous Omicron BA.1/BA.2 infections were more frequent among controls than cases (10.3% vs 0.8%), and their Omicron BA.5 neutralizing titers were 12.8-fold higher than infection-naive individuals. Among cases, preinfection antibody titers were not associated with incidence of long COVID.

CONCLUSIONS

Preinfection immunogenicity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may play a role in protecting against the Omicron BA.5 infection but not preventing long COVID.

Impact of age at vaccination and cervical HPV infection status on binding and neutralizing antibody titers at 10 years after receiving single or higher doses of quadrivalent HPV vaccine

Long-term follow-up of a cohort of unmarried girls who received one, two, or three doses of quadrivalent HPV vaccine, between 10 and 18 years of age, in an Indian multi-centric study allowed us to compare antibody responses between the younger and older age cohorts at 10-years post-vaccination, and study the impact of initiation of sexual activity and cervical HPV infections on antibody levels. Among the younger (10-14 years) recipients of a single dose, 97.7% and 98.2% had detectable binding antibody titers against HPV 16 and HPV 18 respectively at ten years post-vaccination. The proportions among those receiving a single dose at age 15-18 years were 92.3% and 94.2% against HPV 16 and HPV 18 respectively. Mean HPV 16 binding antibody titers were 2.1 folds (95%CI 1.4 to 3.3) higher in those vaccinated at ages 10-14 years, and 1.9 folds (95%CI 1.2 to 3.0) higher in those vaccinated at 15-18 years compared to mean titers seen in the unvaccinated women. Compared to previous timepoints of 36 or 48 months, binding antibodies against HPV 16 and neutralizing antibodies against both HPV 16 and HPV 18 were significantly higher at 10 years. This rise was more pronounced in participants vaccinated at 15-18 years. No association of marital status or cervical HPV infections was observed with the rise in titer. Durability of antibody response in single dose recipients correlated well with the high efficacy of a single dose against persistent HPV 16/18 infections irrespective of age at vaccination, as we reported earlier.

Inducing enhanced neutralizing antibodies against broad SARS-CoV-2 variants through glycan-shielding multiple non-neutralizing epitopes of RBD

Introduction

Since the outbreak of SARS-CoV-2, vaccines have demonstrated their effectiveness in resisting virus infection, reducing severity, and lowering the mortality rate in infected individuals. However, due to the rapid and ongoing mutations of SARS-CoV-2, the protective ability of many available vaccines has been challenged. Therefore, there is an urgent need for vaccines capable of eliciting potent broadly neutralizing antibodies against various SARS-CoV-2 variants.

Methods

In this study, we developed a novel subunit vaccine candidate for SARS-CoV-2 by introducing a series of shielding glycans to the Fc-fused receptor-binding domain (RBD) of the prototypic spike protein. This approach aims to mask non-neutralizing epitopes and focus the immune response on crucial neutralizing epitopes.

Results

All modified sites were confirmed to be highly glycosylated through mass spectrometry analysis. The binding affinity of the glycan-shielded RBD (gsRBD) to the human ACE2 receptor was comparable to that of the wildtype RBD (wtRBD). Immunizing mice with gsRBD when combined with either Freund's adjuvant or aluminum adjuvant demonstrated that the introduction of the glycan shield did not compromise the antibody-inducing ability of RBD. Importantly, the gsRBD significantly enhanced the generation of neutralizing antibodies against SARS-CoV-2 pseudoviruses compared to the wtRBD. Notably, it exhibited remarkable protective activity against Beta (B.1.351), Delta (B.1.617.2), and Omicron (B.1.1.529), approximately 3-fold, 7- fold, and 17-fold higher than wtRBD, respectively.

Discussion

Our data proved this multiple-epitope masking strategy as an effective approach for highly active vaccine production.

Intravitreal injection of a rationally designed AAV capsid library in non-human primate identifies variants with enhanced retinal transduction and neutralizing antibody evasion

Adeno-associated virus (AAV) continues to be the gold standard vector for therapeutic gene delivery and has proven especially useful for treating ocular disease. Intravitreal injection (IVtI) is a promising delivery route because it increases accessibility of gene therapies to larger patient populations. However, data from clinical and non-human primate (NHP) studies utilizing currently available capsids indicate that anatomical barriers to AAV and pre-existing neutralizing antibodies can restrict gene expression to levels that are "sub-therapeutic" in a substantial proportion of patients. Here, we performed a combination of directed evolution in NHPs of an AAV2-based capsid library with simultaneous mutations across six surface-exposed variable regions and rational design to identify novel capsid variants with improved retinal transduction following IVtI. Following two rounds of screening in NHP, enriched variants were characterized in intravitreally injected mice and NHPs and shown to have increased transduction relative to AAV2. Lead capsid variant, P2-V1, demonstrated an increased ability to evade neutralizing antibodies in human vitreous samples relative to AAV2 and AAV2.7m8. Taken together, this study further contributed to our understanding of the selective pressures associated with retinal transduction via the vitreous and identified promising novel AAV capsid variants for clinical consideration.