Immunogenicity and safety of the homogenous booster shot of a recombinant fusion protein vaccine (V-01) against COVID-19 in healthy adult participants primed with a two-dose regimen

BackgroundRising concerns over waning immunity and reduction in neutralizing activity against variants of concern (VOCs) have contributed to deploying booster doses by different strategies to tackle the COVID-19 pandemic. Preliminary findings from Phase I and II have shown that V-01, a recombinant fusion protein vaccine against COVID-19, exhibited favorable safety and immunogenicity profiles in 1060 adult participants of both younger and senior age. Herein, we aimed to assess the immunogenicity and safety for a booster dose in participants previously primed with a two-dose 10g V-01 regimen (day 0, 21) from phase I trial, providing reassuring data for necessity and feasibility of a homogenous booster dose. MethodsWe conducted a single-arm, open-label trial at the Guangdong Provincial Center for Disease Control and Prevention (Gaozhou, China). Forty-three eligible participants who were previously primed 4-5 months earlier with two-dose 10g V-01 regimen from phase I trial received booster vaccination. We primarily assessed the immunogenicity post-booster vaccination, measured by RBD-binding antibodies using ELISA and neutralizing activity against wild-type SARS-CoV-2 and emerging variants of concern (VOCs) using neutralization assays. We secondarily assessed the safety and reactogenicity of the booster vaccination. ResultsThe third dose of V-01 exhibited significant boosting effects of humoral immune response in participants primed with two-dose 10g V-01 regimen regarding both wild-type SARS-CoV-2 and VOCs. We observed a 60.4-folds increase in neutralizing titres against SARS-CoV-2 of younger adults, with GMTs of 17 (95%CI: 12-23) prior to booster vaccination in comparison to 1017 (95%CI: 732-1413) at day 14 post booster vaccination; and a 53.6-folds increase in that of older adults, with GMTs of 14 (95%CI: 9-20) before booster vaccination in comparison to 729(95%CI: 397-1339) at day 14 post-booster vaccination. The neutralizing titres against SARS-CoV-2 Delta strain also demonstrated a sharp increase from the day of pre booster vaccination to day 14 post booster vaccination, with GMTs of 11 (95%CI:8-15) versus 383 (95%CI:277-531) in younger adults (35.4-folds increase), and 6.5(95%CI: 5-8) versus 300(95%CI:142-631) in older adults (46.0-folds increase), respectively. We also observed a considerable and consistent increase of pseudovirus neutralizing titres against emerging VOCs from day 28 post second vaccination to day 14 post booster vaccination, with GMTs of 206 (95%CI:163-259) versus 607 (95%CI: 478-771) for Alpha strain, 54 (95%CI:38-77) versus 329 (95%CI: 255-425) for Beta strain, 219 (95%CI:157-306) versus 647 (95%CI: 484-865) for Delta strain. Our preliminary findings indicate a homogenous booster dose of V-01 was safe and well-tolerated, with overall adverse reactions being absent or mild-to-moderate in severity, and no grade 3 or worse AEs were related to booster vaccination. ConclusionsA homogenous booster immunization in participants receiving a primary series of two-dose V-01 elicited a substantial humoral immune response against wild-type SARS-CoV-2 and emerging VOCs, along with a favorable safety and reactogenicity profile. Our study provided promising data for a homogenous prime-boost strategy using recombinant protein vaccine to tackle the ongoing pandemic, potentially providing broad protection against emerging VOCs and overcoming waning immunity.

Interferon-armed RBD dimer enhances the immunogenicity of RBD for sterilizing immunity against SARS-CoV-2

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global crisis, urgently necessitating the development of safe, efficacious, convenient-to-store, and low-cost vaccine options. A major challenge is that the receptor-binding domain (RBD)-only vaccine fails to trigger long-lasting protective immunity if used solely for vaccination. To enhance antigen processing and cross-presentation in draining lymph nodes (DLNs), we developed an interferon (IFN)-armed RBD dimerized by immunoglobulin fragment (I-R-F). I-R-F efficiently directs immunity against RBD to DLN. A low dose of I-R-F induces not only high titer long-lasting neutralizing antibodies but also comprehensive T cell responses than RBD, and even provides comprehensive protection in one dose without adjuvant. This study shows that the I-R-F vaccine provides rapid and complete protection throughout upper and lower respiratory tracts against high dose SARS-CoV-2 challenge in rhesus macaques. Due to its potency and safety, this engineered vaccine may become one of the next-generation vaccine candidates in the global race to defeat COVID-19.

Ciclamilast ameliorates adjuvant-induced arthritis in a rat model.

We assessed the effect of a novel and selective phosphodiesterase 4 (PDE4) inhibitor, ciclamilast, on chronic inflammation in adjuvant-induced arthritis (AIA), a rat model of rheumatoid arthritis (RA), and acute inflammation in the rat and mouse model of carrageenan-induced paw edema and peritonitis. Our results showed that daily oral administration of ciclamilast at 1, 3, and 10 mg/kg dose-dependently inhibited the increase in hind paw volume of rats with AIA. The inhibition of paw edema was associated with inhibition of both the production of cytokines such as TNF-α, IL-1ß, and IL-6 and cell infiltration assessed in subcutaneous paw tissue. Moreover, there was significantly less tissue destruction in the ciclamilast-treated rats compared to the vehicle-treated rats, as assessed by radiographic analysis and histopathological evaluation. In the two acute inflammation models, ciclamilast inhibited carrageenan-induced paw edema in rats and inflammatory cell migration into the peritoneal cavity in mice in a dose-dependent manner. These results not only suggest that ciclamilast, as a disease-modifying antirheumatic drug (DMARD), can attenuate RA but also provide proof of principle that a PDE4 inhibitor may be useful for the treatment of arthritis.

Cigarette smoke extract-induced BEAS-2B cell apoptosis and anti-oxidative Nrf-2 up-regulation are mediated by ROS-stimulated p38 activation.

Cigarette smoke contains reactive oxygen (ROS) that can cause oxidative stress. It increases the number of apoptotic and necrotic lung cells and further induces the development of chronic airway disease. In this study, we investigated the effects of cigarette smoke extract (CSE) on apoptosis in human bronchial epithelial cells (BEAS-2B). CSE exposure induced ROS generation and p38 mitogen-activated protein kinase (MAPK) activation that are associated with the activation of apoptosis-regulating signal kinase 1 (ASK-1). N-acetylcysteine (a general antioxidant) attenuated the CSE-induced ASK-1 and p38 MAPK activation and cell apoptosis, suggesting a triggering role of ROS in ASK-1/p38 MAPK activation during apoptotic progression. In contrast, the inhibition and knockdown of p38 attenuated the expression of anti-oxidant master NF-E2-related factor 2 (Nrf-2) and CSE-induced apoptosis, suggesting that p38 MAPK modulates Nrf-2 expression and presumably prevents cell apoptosis. Taken together, the data presented in this manuscript demonstrate that the ROS-dependent ASK-1/p38 signaling cascade regulates CSE-induced BEAS-2B cell apoptosis. In addition, anti-oxidative Nrf-2 is also up-regulated by the ROS/p38 signaling cascade in this progression.

Design of next generation antibody drug conjugates / 药学学报

Chemotherapy remains one of the major tools, along with surgery, radiotherapy, and more recently targeted therapy, in the war against cancer. There have appeared a plethora of highly potent cytotoxic drugs but the poor discriminability between cancerous and healthy cells of these agents limits their broader application in clinical settings. Therapeutic antibodies have emerged as an important class of biological anticancer agents, thanks to their ability in specific binding to tumor-associated antigens. While this important class of biologics can be used as single agents for the treatment of cancer through antibody-dependent cell cytotoxicity (ADCC), their therapeutical efficacy is often limited. Antitumor antibody drug conjugates (ADCs) combine the target-specificity of monoclonal antibody (mAb) and the highly active cell-killing drugs, taking advantages of the best characteristics out of both components. Thus, insufficiency of most naked mAbs in cancer therapy has been circumvented by arming the immunoglobulin with cytotoxic drugs. Here mAbs are used as vehicles to transport potent payloads to tumor cells. ADCs contain three main components: antibody, linker and cytotoxics (also frequently referred as payload). Antibodies can recognize and specifically bind to the tumor-specific antigens, leading to an antibody-assisted internalization, and payload release. While ADC has demonstrated tremendous success, a number of practical challenges limit the broader applications of this new class of anticancer therapy, including inefficient cellular uptake, low cytotoxicity, and off-target effects. This review article aims to cover recent advances in optimizing linkers with increased stability in circulation while allowing efficient payload release within tumor cells. We also attempt to provide some practical strategies in resolving the current challenges in this attractive research area, particularly to those new to the field.

The tumor immunosuppressive microenvironment impairs the therapy of anti-HER2/neu antibody

It has been well established that immune surveillance plays critical roles in preventing the occurrence and progression of tumor. More and more evidence in recent years showed the host anti-tumor immune responses also play important roles in the chemotherapy and radiotherapy of cancers. Our previous study found that tumor- targeting therapy of anti-HER2/neu mAb is mediated by CD8(+) T cell responses. However, we found here that enhancement of CD8(+) T cell responses by combination therapy with IL-15R/IL-15 fusion protein or anti-CD40, which are strong stimultors for T cell responses, failed to promote the tumor therapeutic effects of anti-HER2/neu mAb. Analysis of tumor microenviornment showed that tumor tissues were heavily infiltrated with the immunosuppressive macrophages and most tumor infiltrating T cells, especially CD8(+) T cells, expressed high level of inhibitory co-signaling receptor PD-1. These data suggest that tumor microenvironment is dominated by the immunosuppressive strategies, which thwart anti-tumor immune responses. Therefore, the successful tumor therapy should be the removal of inhibitory signals in the tumor microenvironment in combination with other therapeutic strategies.

Effects of lymphotoxin beta receptor blockade on intestinal mucosal immunity.

BACKGROUND: Mucosal addressin cellular adhesion molecule-1 (MAdCAM-1) directs lymphocyte migration into gut-associated lymphoid tissue (GALT) through Peyer's patches (PPs). Parenteral nutrition (PN) impairs mucosal immunity by reducing PPs MAdCAM-1 expression, T and B cells in GALT, and intestinal and respiratory immunoglobulin (Ig) A levels. We previously showed that PN reduces lymphotoxin beta receptor blockade (LTbetaR) in PPs and intestine, and that stimulation with LTbetaR agonist antibodies reverses these defects. To confirm that LTbetaR regulates transcription of MAdCAM-1 message and more fully understand the effects of LTbetaR on MAdCAM-1 function within the mucosal immune system, we studied the effect of LTbetaR blockade with a chimeric LTbetaR Ig-fusion protein on MAdCAM-1 mRNA levels, PP lymphocyte mass and IgA levels in the intestinal and respiratory tracts. METHODS: Mice were cannulated and killed 3 days after receiving chow + control Ig, chow + LTbetaR-Ig fusion protein (100 microg IV), or PN + control Ig. The PPs of half of the animals were processed for lymphocyte count, and the other half were processed for complementary DNA and subsequent polymerase chain reaction (PCR). mRNA levels of MAdCAM-1 were determined by real-time PCR; intestinal and respiratory IgA levels were measured by ELISA. RESULTS: PN significantly reduced PP lymphocyte mass, MAdCAM-1 mRNA, and intestinal IgA. As anticipated, LTbetaR blockade significantly decreased PP cells and MAdCAM-1 mRNA, but not intestinal IgA because chow feeding was maintained. Both LTbetaR blockade and PN decreased nasal IgA, but not significantly. CONCLUSIONS: LTbetaR blockade in chow animals significantly reduces transcription of MAdCAM-1 gene and PPs lymphocyte mass. These data implicate inadequate LTbetaR signaling as a major mechanism for decreased GALT cells with lack of enteral stimulation, and further establish the role of LTbetaR in the mucosal immune system.