Recent studies have uncovered evidences for pro-tumorigenic activities attributed to IL-11, prompting a renewed focus on therapeutic strategies targeting IL-11 signaling for anti-tumor treatment. Here, we introduce 9MW3811, a monoclonal antibody designed to neutralize IL-11 effectively. By disrupting the IL-11/IL-11Rα/gp130 complex, 9MW3811 inhibits JAK/STAT3 signaling, significantly reducing tumor growth in diverse mouse models. More importantly, 9MW3811 synergizes with anti-PD-1 therapy, even in PD-1 non-responsive models like CT26. Single-cell RNA-seq analysis reveals that 9MW3811 remodels the tumor microenvironment by enhancing CD8+ T cell infiltration and reversing T cell exhaustion via upregulated XCL1 and downregulated CCL7, boosting anti-tumor cytotoxicity. Furthermore, 9MW3811 counteracts PD-1-induced T cell exhaustion, with anti-PD-1 antibodies effectively mitigating PD-1 upregulation post-9MW3811 treatment. These compelling findings support ongoing clinical trials of 9MW3811, aiming to translate these preclinical insights into therapeutic benefits for cancer patients.

Background: Even though PD-1/PD-L1 is an identified key "don't find me" signal to active adaptive immune system for cancer treatment, the overall response rate (ORR) for all cancer patients is still limited.Other effective therapeutic modalities to bridge the innate and adaptive immunity to improve ORR are urgently needed.Recently, CD47/SIRPα interaction is confirmed as a critical "don't eat me" signal to active innate immunity.However, the red blood cell (RBC) toxicity is the big concern for the development of CD47-based anti-cancer therapeutics.Methods: Here, we report the development of a CD47/PD-L1 bispecific antibody 6MW3211 to block both PD-1/PD-L1 and CD47/SIRPα signals, and studied the effects of 6MW3211 on anti-tumor immune functions in vitro and in vivo.The pharmacokinetic and toxicity profiles of 6MW3211 were evaluated in GLP non-human primate (NHP) studies. Results:The dual immune checkpoint inhibitory signaling blocker 6MW3211 shows high binding affinity to PD-L1 and low binding affinity to CD47.This inequivalent binding affinity design makes 6MW3211 preferentially bound to PD-L1 on tumor cells followed by disrupting the interaction of CD47/SIRPα.Complex structure determination and flow cytometry assay demonstrated that 6MW3211 has no binding to either human or rhesus monkey RBCs.6MW3211 effectively blocked both PD-1/DP-L1 and CD47/SIRPα signaling and promoted macrophage phagocytosis of tumor cells.Potent therapeutic efficacies of 6MW3211 in three different mouse models were further observed.Moreover, 6MW3211 was demonstrated to have a fairly good safety profile in a GLP NHP study.In addition, multiplex fluorescent immunohistochemistry (mIHC) staining shows that PD-L1 and CD47 co-express on several different types of human tumor tissues.Conclusions: These results support the development of 6MW3211 for the treatment of PD-L1 and CD47 double positive cancers.

Understanding the underlying molecular mechanisms behind ADE of SARS-CoV-2 is critical for development of safe and effective therapies. Here, we report that two neutralizing mAbs, MW01 and MW05, could enhance the infection of SARS-CoV-2 pseudovirus on FcγRIIB-expressing B cells. X-ray crystal structure determination and S trimer-binding modeling showed that MW01 and MW05 could bind to RBDs in S trimer with both "up" and "down" states. While, the neutralizing mAb MW07, which has no ADE activity only binds to RBD in S trimer with "up" state. Monovalent MW01 and MW05 completely diminished the ADE activity compared with their bivalent counterparts. Moreover, both macropinocytosis and endocytosis are confirmed involving in ADE of SARS-CoV-2 pseudoviral infection. Blocking endosome transportation and lysosome acidification could inhibit the ADE activity mediated by MW05. Together, our results identified a novel ADE mechanism of SARS-CoV-2 pseudovirus in vitro, FcγRIIB-mediated uptake of SARS-CoV-2/mAb complex with bivalent interaction.

Antibody-dependent enhancement (ADE) has been reported for SARS-CoV and MERS-CoV, suggesting the risk of ADE for antibody-based SARS-CoV-2 vaccines and therapeutics. Understanding the underlying molecular mechanisms behind ADE of SARS-CoV-2 is critical for development of safe and effective therapies. Here, we report that two neutralizing mAbs MW01 and MW05 could enhance the infection of SARS-CoV-2 on FcγRIIB-expressing B cells. Enhancing the interaction of Fc with FcγRIIB could increase the ADE activity mediated by MW01 and MW05. Expression of other FcγRs, such as FcγRIA and FcγRIIA, could decrease ADE activity of these two mAbs by competing with FcγRIIB. X-ray crystal structure determination and S trimer-binding modeling showed that MW01 and MW05 can bind to RBDs in S trimer with both “up” and “down” states. While, the neutralizing mAb MW07, which has no ADE activity only binds to RBD in S trimer with “up” state. Monovalent MW01 and MW05 completely diminished the ADE activity compared with their bivalent counterparts. Moreover, both macropinocytosis and endocytosis are confirmed involving in ADE of SARS-CoV-2 infection. Blocking endosome transportation and lysosome acidification could inhibit the ADE activity mediated by MW05. Together, our results identified a novel ADE mechanism of SARS-CoV-2, FcγRIIB-mediated uptake of SARS-CoV-2/mAb complex with bivalent interaction. These findings provide a novel perspective on the mechanism of ADE of SARS-CoV-2, which is informative to the development of safer therapeutics and vaccines. Funding Information: This work was supported by National Key R&D Program (2020YFC0848600 to S.W. and 2020YFC0860700 to L.W.). Declaration of Interests: X.G., S.W., S.J., W.J. and C.G. are listed as inventors on the licensed patents for MW05 and MW07. S.W., S.J., W.J., M.W., Z.L., C.G., B.C., H.C., A.W., G.L., C.G., X.G., J.Z. and D.L. are employees of Mabwell (Shanghai) Bioscience Co., Ltd. and may hold shares in Mabwell (Shanghai) Bioscience Co., Ltd. The other authors declare no competing interests.

Efficacious interventions are urgently needed for the treatment of COVID-19. Here, we report a monoclonal antibody (mAb), MW05, with SARS-CoV-2 neutralizing activity by disrupting the interaction of receptor binding domain (RBD) with angiotensin-converting enzyme 2 (ACE2) receptor. Crosslinking of Fc with FcγRIIB mediates antibody-dependent enhancement (ADE) activity by MW05. This activity is eliminated by introducing the LALA mutation to the Fc region (MW05/LALA). Potent prophylactic and therapeutic effects against SARS-CoV-2 are observed in rhesus monkeys. A single dose of MW05/LALA blocks infection of SARS-CoV-2 in prophylactic treatment and clears SARS-CoV-2 in three days in a therapeutic treatment setting. These results pave the way for the development of MW05/LALA as an antiviral strategy for COVID-19.

Programmed cell death 1 (PD-1) is inhibitory receptor and immune checkpoint protein. Blocking the interaction of PD-1 and its ligands PD-L1/ L2 is able to active T-cell-mediated antitumor response. Monoclonal antibody-based drugs targeting PD-1 pathway have exhibited great promise in cancer therapy. Here we show that MW11-h317, an anti-PD-1 monoclonal antibody, displays high affinity for PD-1 and blocks PD-1 interactions with PD-L1/L2. MW11-h317 can effectively induce T-cell-mediated immune response and inhibit tumor growth in mouse model. Crystal structure of PD-1/MW11-h317 Fab complex reveals that both the loops and glycosylation of PD-1 are involved in recognition and binding, in which Asn58 glycosylation plays a critical role. The unique glycan epitope in PD-1 to MW11-h317 is different from the first two approved clinical PD-1 antibodies, nivolumab and pembrolizumab. These results suggest MW11-h317 as a therapeutic monoclonal antibody of PD-1 glycosylation-targeting which may become efficient alternative for cancer therapy.

Meeting abstracts Systemic lupus erythematosus is a chronic, heterogeneous autoimmune disease, and there is no specific drug for its effective treatment, which may be because of its complexity on pathogenic mechanism. A multitude of studies of SLE in the last decade have accentuated a central role

Meeting abstracts We generated a novel fully human anti-EGFR antibody showed lower toxicity and higher efficacy in the preclinical, toxicological and pharmacological studies when compared to a commercial drug Cetuximab. In this research, we aimed to understand the probably mechanism. Firstly, the