Supplementary Fig.6 including its legend

The ganglioside GD2 is an attractive cancer target because of its high expression in neuroblastoma and other solid tumors with limited normal-tissue distribution. Despite regulatory approvals of three anti-GD2 antibodies, clinical efficacy remains limited by neurotoxicity, suboptimal affinity for antibody-dependent cellular cytotoxicity (ADCC), and immunogenicity. Developing a highly effective, less toxic anti-GD2 agent remains an unmet need. In this study, a novel anti-GD2 murine antibody, CA450, was identified by immunizing mice with GD2 conjugated to keyhole limpet hemocyanin or Qβ virus-like particles, followed by phage display screening. The humanized version, hCA450-21, displayed higher cell-binding activity than ch14.18 and Hu3F8, along with excellent specificity and internalization capacity. To overcome the limitations of traditional anti-GD2 antibody therapy, hCA450-21 was engineered and conjugated to exatecan to create an antibody-drug conjugate (ADC), which may reduce or avoid neurotoxicity by employing a mechanism distinct from ADCC and complement-dependent cytotoxicity. The hCA450-21.1-LA-68B ADC demonstrated potent in vitro cytotoxicity against glioblastoma, melanoma, and breast cancer cell lines and in vivo tumor growth inhibition in LN229 and SK-MEL-5 xenograft models. Toxicity studies in mice showed a favorable safety profile, with reduced neurotoxicity compared with naked antibody therapy by ch14.18-IgG1 and hCA450-21.1-IgG1. The crystal structure of the hCA450-21.1 Fab-GD2 complex was resolved at 1.69 Å, revealing unique hydrogen bonds and hydrophobic interactions that contribute to its high specificity and affinity. Overall, the novel hCA450-21.1-LA-68B ADC shows preclinical efficacy and reduced toxicity, particularly neurotoxicity, indicating potential as a safer and more effective therapy for GD2-positive pediatric and adult tumors.

Supplementary Fig.7 including its legend

Supplementary Fig.1 including its legend

The constant emergence of SARS-CoV-2 variants continues to impair the efficacy of existing neutralizing antibodies, especially XBB.1.5 and EG.5, which showed exceptional immune evasion properties. Here, we identify a highly conserved neutralizing epitope targeted by a broad-spectrum neutralizing antibody BA7535, which demonstrates high neutralization potency against not only previous variants, such as Alpha, Beta, Gamma, Delta and Omicron BA.1-BA.5, but also more recently emerged Omicron subvariants, including BF.7, CH.1.1, XBB.1, XBB.1.5, XBB.1.9.1, EG.5. Structural analysis of the Omicron Spike trimer with BA7535-Fab using cryo-EM indicates that BA7535 recognizes a highly conserved cryptic receptor-binding domain (RBD) epitope, avoiding most of the mutational hot spots in RBD. Furthermore, structural simulation based on the interaction of BA7535-Fab/RBD complexes dissects the broadly neutralizing effect of BA7535 against latest variants. Therapeutic and prophylactic treatment with BA7535 alone or in combination with BA7208 protected female mice from the circulating Omicron BA.5 and XBB.1 variant infection, suggesting the highly conserved neutralizing epitope serves as a potential target for developing highly potent therapeutic antibodies and vaccines.

SARS-CoV-2 Omicron subvariants have demonstrated extensive evasion from monoclonal antibodies (mAbs) developed for clinical use, which raises an urgent need to develop new broad-spectrum mAbs. Here, we report the isolation and analysis of two anti-RBD neutralizing antibodies BA7208 and BA7125 from mice engineered to produce human antibodies. While BA7125 showed broadly neutralizing activity against all variants except the Omicron sublineages, BA7208 was potently neutralizing against all tested SARS-CoV-2 variants (including Omicron BA.1-BA.5) except Mu. By combining BA7208 and BA7125 through the knobs-into-holes technology, we generated a biparatopic antibody BA7208/7125 that was able to neutralize all tested circulating SARS-CoV-2 variants. Cryo-electron microscopy structure of these broad-spectrum antibodies in complex with trimeric Delta and Omicron spike indicated that the contact residues are highly conserved and had minimal interactions with mutational residues in RBD of current variants. In addition, we showed that administration of BA7208/7125 via the intraperitoneal, intranasal, or aerosol inhalation route showed potent therapeutic efficacy against Omicron BA.1 and BA.2 in hACE2-transgenic and wild-type mice and, separately, effective prophylaxis. BA7208/7125 thus has the potential to be an effective candidate as an intervention against COVID-19.

High tumor regulatory T (Treg) cell infiltration is associated with poor prognosis of many cancers. CD25 is highly expressed on tumor Treg cells and is a potential target for Treg deletion. Previously characterized anti-CD25 antibodies appear to have limited efficacy in tumor inhibition. Here we identified two human anti-CD25 antibodies, BA9 and BT942, which did not prevent the activation of IL-2R signaling pathway by IL-2. BT942 had weaker binding and cytotoxic activity to human CD25-expressing cell lines than BA9. But both demonstrated significant tumor growth inhibition in early and late-stage animal cancer models. BT942 resulted in a higher expansion of CD8+ T cells and CD4+ T cells in tumor microenvironment in mouse MC38 model compared to BA9. BT942 also demonstrated significant higher tumor growth inhibition and higher expansion of CD8+ T cells and CD4+ T cells in combination with an anti-PD1 antibody. Pharmacokinetic study of BT942 in cynomolgus monkeys demonstrated a half-life of 206.97 ± 19.03 h. Structural analysis by cryo-EM revealed that BT942 recognizes an epitope on opposite side of the CD25-IL-2 binding site, consistent with no IL-2 signaling blockade in vitro. BT942 appears to be an excellent candidate for cancer immunotherapy.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the ongoing COVID-19 pandemic, which has resulted in more than two million deaths at 2021 February . There is currently no approved therapeutics for treating COVID-19. The SARS-CoV-2 Spike protein is considered a key therapeutic target by many researchers. Here we describe the identification of several monoclonal antibodies that target SARS-CoV-2 Spike protein. One human antibody, CA521 FALA , demonstrated neutralization potential by immunizing human antibody transgenic mice. CA521 FALA showed potent SARS-CoV-2-specific neutralization activity against SARS-CoV-2 pseudovirus and authentic SARS-CoV-2 infection in vitro. CA521 FALA also demonstrated having a long half-life of 9.5 days in mice and 9.3 days in rhesus monkeys. CA521 FALA inhibited SARS-CoV-2 infection in SARS-CoV-2 susceptible mice at a therapeutic setting with virus titer of the lung reduced by 4.5 logs. Structural analysis by cryo-EM revealed that CA521 FALA recognizes an epitope overlapping with angiotensin converting enzyme 2 (ACE2)-binding sites in SARS-CoV-2 RBD in the Spike protein. CA521 FALA blocks the interaction by binding all three RBDs of one SARS-CoV-2 spike trimer simultaneously. These results demonstrate the importance for antibody-based therapeutic interventions against COVID-19 and identifies CA521 FALA a promising antibody that reacts with SARS-CoV-2 Spike protein to strongly neutralize its activity.

This study investigated the use of a newly developed chitosan-Ca pectinate microbead formulation for the colon-targeted delivery of anti-A/B toxin immunoglobulin of egg yolk (IgY) to inhibit toxin binding to colon mucosa cells. The effect of the three components (pectinate, calcium chloride, and chitosan) used for the microbead production was examined with the aim of identifying the optimal levels to improve drug encapsulation efficiency, swelling ratio, and cumulative IgY release rate. The optimized IgY-loaded bead component was pectin 5% (w/v), CaCl2 3% (w/v), and chitosan 0.5% (w/v). Formulated beads were spherical with 1.2-mm diameter, and the drug loading was 45%. An in vitro release study revealed that chitosan-Ca pectinate microbeads inhibited IgY release in the upper gastrointestinal tract and significantly improved the site-specific release of IgY in the colon. An in vivo rat study demonstrated that 72.6% of biologically active IgY was released specifically in the colon. These results demonstrated that anti-A/B toxin IgY-loaded chitosan-Ca pectinate oral microbeads improved IgY release behavior in vivo, which could be used as an effective oral delivery platform for the biological treatment of Clostridium difficile infection (CDI).

The incidence of Clostridium difficile infection has increased in Western world in the past 10 years, similar infection rates are also reported in developing countries such as China. Current antibiotics treatments have recurrence rates between 15% and 30%. IgY antibodies against toxin A of C. difficile could protect animal models from the challenge of lethal dose of C. difficile spores. However, IgY is sensitive to the low pH environment of the stomach and proteinases in the intestine. The objective of this study was to prepare colonic-specific delivery system of toxin A antigen-specific IgY to block the recognition of toxin A to the colon mucosa cells. Egg-laying hens were immunized with purified C. difficile toxin A C-terminal domain for 3 times, then egg IgY against the recombinant ToxA-C protein was purified from immunized egg yolk and frozen dried. IgY-loaded microbeads were prepared using mini fluid bed system; the loading efficiency was 21%. The pH and temperature stabilities of the microbeads were assayed. The IgY-loaded microbeads coated with 35% Eudragit S100 had colonic-specific IgY release specificity both in vitro and in vivo, the colonic-specific release of biological active IgY was 87.5% in the rat. Our study provides a new option for the biological treatment C. difficile infection.

Objective To obtain recombinant human stanniocalcin 1 ( STC1 ) with biological activity in Escheri.coli cells expression.Methods The gene was cloned into pET32b( +) vector by fused with thioredoxin and His tag .E.coli BL21(DE3) competent cells were transfomed by the recombinant vector .After renaturation, the fusion protein was digested with thrombin and intact STC1 protein was purified from the digested protein using Ni ion affinity chromatography .Recombi-nant humanSTC1 protein was confirmed by Western blot analysis using goat anti-STC1 antibody.The biological activity of STC1 in rat was assayed using standard method for assessment of renal function .Results The recombinant human STC 1 fu-sion protein is successfully expressed in Escherichia coli, the fusion protein was purified by affinity chromatography from the inclusion body and renaturated .Intact hSTC1 protein was released by thrombin digestion and purified by Ni ion affinity col-umn.The intact STC1 proteins was confirmed by Western blot analysis .Rat bioassay revealed that STC1 boosted phosphate reabsorption.Conclusion Recombinant STC1 protein was successfully expressed and has native biological activities .This protein could be used as an antigen for the preparation of monoclonal antibody against humanSTC 1.

Objective To express the C-terminal domains of toxin A for the development of egg yolk immunoglobulin against Clostridium difficile-associated diarrhea.Methods The DNA sequence of C-terminal domain of toxin A(TcdA-C) was optimized and synthesized.The gene was cloned into pET32b(+) vector before the recombinant vectors were transformed to E.coli BL21(DE3) competent cells.Fusion protein was purified by high affinity Ni+resin.After thrombin digestion,TcdA-C without tag was recovered from flow through of another round of high affinity Ni+resin purification.Biological activities of TcdA-C were assayed.High potency specific IgY antibodies against TcdA-C were prepared from immunization of egg laying hens,then the IgY antibodies were purified.Results Soluble recombinant TcdA-C protein was expressed in E.coli at a high level,and with good biological activity.The titer of prepared TcdA-C specific IgY antibodies was 1∶ 50 000.Purified IgY had neutralization activity in rabbit intestinal loop test.Conclusion Recombinant TcdA-C protein with native biological activities is successfully expressed and purified,which helps develop recombinant vaccines of C.difficile.IgY antibodies against the TcdA-C protein can be used for diagnosis and treatment of C.difficile-associated diarrhea.