Upon binding to the host cell receptor, CD4, the pretriggered (State-1) conformation of the human immunodeficiency virus (HIV-1) envelope glycoprotein (Env) trimer undergoes transitions to downstream conformations important for virus entry. State 1 is targeted by most broadly neutralizing antibodies (bNAbs), whereas downstream conformations elicit immunodominant, poorly neutralizing antibody (pNAb) responses. Extraction of Env from the membranes of viruses or Env-expressing cells disrupts the metastable State-1 Env conformation, even when detergent-free approaches like styrene-maleic acid lipid nanoparticles (SMALPs) are used. Here, we combine three strategies to solubilize and purify mature membrane Envs that are antigenically native (i.e., recognized by bNAbs and not pNAbs): (1) solubilization of Env with a novel amphipathic copolymer, Amphipol A18; (2) use of stabilized pretriggered Env mutants; and (3) addition of the State-1-stabilizing entry inhibitor, BMS-806. Amphipol A18 was superior to the other amphipathic copolymers tested (SMA and AASTY 11-50) for preserving a native Env conformation. A native antigenic profile of A18 Env-lipid-nanodiscs was maintained for at least 7 days at 4°C and 2 days at 37°C in the presence of BMS-806 and was also maintained for at least 1 h at 37°C in a variety of adjuvants. The damaging effects of a single cycle of freeze-thawing on the antigenic profile of the A18 Env-lipid-nanodiscs could be prevented by the addition of 10% sucrose or 10% glycerol. These results underscore the importance of the membrane environment to the maintenance of a pretriggered (State-1) Env conformation and provide strategies for the preparation of lipid-nanodiscs containing native membrane Envs.IMPORTANCEThe human immunodeficiency virus (HIV-1) envelope glycoproteins (Envs) mediate virus entry into the host cell and are targeted by neutralizing antibodies elicited by natural infection or vaccines. Detailed studies of membrane proteins like Env rely on purification procedures that maintain their natural conformation. In this study, we show that an amphipathic copolymer A18 can directly extract HIV-1 Env from a membrane without the use of detergents. A18 promotes the formation of nanodiscs that contain Env and membrane lipids. Env in A18-lipid nanodiscs largely preserves features recognized by broadly neutralizing antibodies (bNAbs) and conceals features potentially recognized by poorly neutralizing antibodies (pNAbs). Our results underscore the importance of the membrane environment to the native conformation of HIV-1 Env. Purification methods that bypass the need for detergents could be useful for future studies of HIV-1 Env structure, interaction with receptors and antibodies, and immunogenicity.

The TrkB receptor, which is highly expressed in various human cancers and considered a pro-oncogene, was targeted to develop neutralizing monoclonal antibodies against its immunoglobulin-like (Ig-like) domains. Recombinant TrkB-IgL peptide, including the Ig-like C2 type 1 (Ig-C2-type 1) and Ig-like C2 type 2 (Ig-C2-type 2) domains, was expressed and purified from E. coli. Mice were immunized with this peptide, and hybridoma clones producing anti-TrkB-IgL antibodies were generated. Among 23 ELISA-positive TrkB-IgL hybridoma clones, four (TrkB-IgL 5.11, 4.11, 4.6, 4.3) showed anti-proliferative effects compared to the control on human breast cancer (MCF-7) and human colon cancer (HCT116) cells, as assessed using the xCELLigence system. Western blot analysis revealed that TrkB-IgL 5.11 and 4.11 significantly suppressed TrkB-mediated signaling pathways compared to the control. Purified TrkB-IgL monoclonal antibodies (mAbs) exhibited anti-proliferative effects compared to both positive and negative controls using the xCELLigence system. The TrkB-IgL 5.11 mAb notably suppressed phosphorylation of TrkB, Akt, and ERK and induced Caspase-3 and Caspase-9 activities in a dose-dependent manner, as determined by Western blotting. Additionally, immunostaining confirmed the localization of these mAbs on the SH-SY5Y cell membrane, which is known for high TrkB expression. In conclusion, the TrkB-IgL 5.11 antibody effectively inhibits cancer cell proliferation and induces apoptosis by suppressing key signaling pathways. These findings demonstrate the potential of this antibody as a therapeutic agent for cancers that overexpress TrkB. Additionally, it is considered a promising candidate for humanization, which would facilitate its application in cancer treatment.
UNASSIGNED: The online version contains supplementary material available at 10.1007/s13205-024-04063-x.

Bovine herpesvirus 1 (BoHV-1), a significant pathogen in the alpha-herpesvirus subfamily, primarily infects cattle and causes the upper respiratory disease known as infectious bovine rhinotracheitis (IBR). In silico studies evaluated the BoHV-1 D protein to be non-allergenic, non-toxic, and highly antigenic, highlighting its potential as an antigen for vaccine development. Therefore, this study aimed to evaluate the efficacy of a subunit vaccine using the ectodomain of glycoprotein D (gD34-380) as an antigen. The truncated gD was successfully cloned and expressed in both Escherichia coli (E. coli, termed EgD) and baculovirus (termed BgD) systems, with expected molecular weights of 65kDa and 50kDa, respectively. For the vaccine formulation, the gD proteins were used either alone or in combination with in-house inactivated BoHV-1. Vaccination of mice and bovines showed that baculovirus-expressed gD34-380 accelerated the antibody response. Moreover, the BgD-vaccinated group also showed significantly higher neutralizing antibody levels against BoHV-1 than the control group (p<0.0001). In conclusion, our study found that BgD from BoHV-1 can increase the immune response and enhance vaccine efficacy.

UNASSIGNED: Visceral adiposity is a significant risk factor for severe COVID-19. However, the impact of the Chinese visceral adiposity index (CVAI) on the efficacy of SARS-CoV-2 vaccines remains poorly understood. This study aims to explore the impact of CVAI on the production of neutralizing antibodies (NAb) in inactivated SARS-CoV-2 vaccines and the potential mechanism, thereby optimizing vaccination guidance.
UNASSIGNED: In this cross-sectional study, 206 health workers (completed two SARS-CoV-2 vaccination on February 8th and March 10th, 2021, respectively) were recruited. All baseline anthropometric parameters of the participants were collected, and venous blood samples were obtained 6 weeks later to measure peripheral innate immune cells, inflammatory cytokines, and NAb titers against SARS-CoV-2. CVAI were calculated according to the formula and divided participants into two groups depending on CVAI median.
UNASSIGNED: The median NAb titer among healthcare workers was 12.94 AU/mL, with an efficacy of 87.86% for the SARS-CoV-2 vaccine. NAb titers were lower in the CVAI dysfunction group than in the CVAI reference group (median: 11.40 AU/mL vs 15.57 AU/mL), the hsCRP levels (median: 0.50 mg/L vs 0.30 mg/L) and peripheral monocyte count (mean: 0.47 × 109/L vs 0.42 × 109/L) in the CVAI dysfunction group were higher than in the CVAI reference group. Additionally, CVAI showed positive correlations with hsCRP, monocytes, lymphocytes, and B-lymphocytes, and a negative correlation with NAb titers.
UNASSIGNED: CVAI may inhibit SARS-CoV-2 neutralizing antibody expression through inducing immune dysfunction and chronic inflammation. Thus, more attention should be paid to the vaccination for high CVAI population to improve the effectiveness of vaccination, which could provide more robust support for COVID-19 epidemic prevention and control.

We have previously reported a clinical case in which a hospitalized patient with a history of hematopoietic stem cell transplantation for acute myeloid leukemia was persistently infected with SARS-CoV-2. This study investigated the neutralizing activity of patient sera against cultured viruses isolated at each time point. We also continued to decipher and analyze the whole-genome sequence of the virus. The results showed that the neutralizing activity against the cultured virus at each time point was higher in the sera collected in the late stage of infection. However, the cultured virus collected in the late stage of infection was less likely to be neutralized not only by the sera collected in the early stage of infection but also by the sera collected in the late stage. Moreover, the virus mutated in a manner that allowed it to escape neutralizing antibodies in a host vulnerable to prolonged infection, such as immunocompromised patients.

The development of broadly neutralizing antibody (bnAb)-based therapeutic HIV-1 vaccines and cure concepts depends on monitoring bnAb plasma activity in people with HIV (PWH) on suppressive antiretroviral therapy (ART). To enable this, analytical strategies must be defined to reliably distinguish antibody-based neutralization from drug inhibition. Here, we explore strategies that either utilize drug-resistant viruses or remove drugs from plasma. We develop ART-DEX (ART dissociation and size exclusion), an approach which quantitatively separates drugs from plasma proteins following pH-triggered release allowing accurate definition of antibody-based neutralization. We demonstrate that ART-DEX, alone or combined with ART-resistant viruses, provides a highly effective and scalable means of assessing antibody neutralization during ART. Implementation of ART-DEX in standard neutralization protocols should be considered to enhance the analytical capabilities of studies evaluating bnAb therapeutics and therapeutic vaccines, furthering the development of advanced ART and HIV-1 cure strategies.

Host immunity is central to the virus\'s spread dynamics, which is significantly influenced by vaccination and prior infection experiences. In this work, we analyzed the co-evolution of SARS-CoV-2 mutation, angiotensin-converting enzyme 2 (ACE2) receptor binding, and neutralizing antibody (NAb) responses across various variants in 822 human and mice vaccinated with different non-Omicron and Omicron vaccines is analyzed. The link between vaccine efficacy and vaccine type, dosing, and post-vaccination duration is revealed. The classification of immune protection against non-Omicron and Omicron variants is co-evolved with genetic mutations and vaccination. Additionally, a model, the Prevalence Score (P-Score) is introduced, which surpasses previous algorithm-based models in predicting the potential prevalence of new variants in vaccinated populations. The hybrid vaccination combining the wild-type (WT) inactivated vaccine with the Omicron BA.4/5 mRNA vaccine may provide broad protection against both non-Omicron variants and Omicron variants, albeit with EG.5.1 still posing a risk. In conclusion, these findings enhance understanding of population immunity variations and provide valuable insights for future vaccine development and public health strategies.

Therapy against the Hepatitis C virus (HCV) has significantly improved with the introduction of direct-acting antiviral drugs (DAAs), achieving over 95% sustained virological response (SVR). Despite this, the development of an effective anti-HCV vaccine remains a critical challenge due to the low number of patients treated with DAAs and the occurrence of HCV reinfections in high-risk groups. Current vaccine strategies aim to stimulate either B-cell or T-cell responses. Vaccines based on E1 and E2 proteins can elicit broad cross-neutralizing antibodies against all major HCV genotypes, though with varying efficiencies and without full protection against infection. In humans, the neutralizing antibodies induced by such vaccines mainly target the AR3 region, but their levels are generally insufficient for broad neutralization. Various HCV proteins expressed through different viral vectors have been utilized to elicit T cell immune responses, showing sustained expansion of HCV-specific effector memory T cells and improved proliferation and polyfunctionality of memory T cells over time. However, despite these advancements, the frequency and effectiveness of T-cell responses remain limited.

Snake venoms are cocktails of biologically active molecules that have evolved to immobilize prey, but can also induce a severe pathology in humans that are bitten. While animal-derived polyclonal antivenoms are the primary treatment for snakebites, they often have limitations in efficacy and can cause severe adverse side effects. Building on recent efforts to develop improved antivenoms, notably through monoclonal antibodies, requires a comprehensive understanding of venom toxins. Among these toxins, snake venom metalloproteinases (SVMPs) play a pivotal role, particularly in viper envenomation, causing tissue damage, hemorrhage and coagulation disruption. One of the current challenges in the development of neutralizing monoclonal antibodies against SVMPs is the large size of the protein and the lack of existing knowledge of neutralizing epitopes. Here, we screened a synthetic human antibody library to isolate monoclonal antibodies against an SVMP from saw-scaled viper (genus Echis) venom. Upon characterization, several antibodies were identified that effectively blocked SVMP-mediated prothrombin activation. Cryo-electron microscopy revealed the structural basis of antibody-mediated neutralization, pinpointing the non-catalytic cysteine-rich domain of SVMPs as a crucial target. These findings emphasize the importance of understanding the molecular mechanisms of SVMPs to counter their toxic effects, thus advancing the development of more effective antivenoms.

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron subvariants raises concerns regarding the effectiveness of immunity acquired from previous Omicron subvariants breakthrough infections (BTIs) or reinfections (RIs) against the current circulating Omicron subvariants. In this study, we prospectively investigate the dynamic changes of virus-specific antibody and T cell responses among 77 adolescents following Omicron BA.2.3 BTI with or without subsequent Omicron BA.5 RI. Notably, the neutralizing antibodies (NAbs) titers against various detected SARS-CoV-2 variants, especially the emerging Omicron CH.1.1, XBB.1.5, XBB.1.16, EG.5.1, and JN.1 subvariants, exhibited a significant decrease along the time. A lower level of IgG and NAbs titers post-BTI was found to be closely associated with subsequent RI. Elevated NAbs levels and shortened antigenic distances were observed following Omicron BA.5 RI. Robust T cell responses against both Omicron BA.2- and CH.1.1-spike peptides were observed at each point visited. The exposure to Omicron BA.5 promoted phenotypic differentiation of virus-specific memory T cells, even among the non-seroconversion adolescents. Therefore, updated vaccines are needed to provide effective protection against newly emerging SARS-CoV-2 variants among adolescents.