InVivoMAb anti-mouse 4-1BB (CD137)

Chronic inflammation in intermediate/advanced tumors drives burdensome protumor immune cell communication, thereby weakening immunotherapy. Conventional anti-inflammatory therapies focus on alleviating chronic inflammation whereas ignore dysfunction and scarcity of myeloid and T cells, which hinder their intercellular communication restoration. To address the dilemma, an inflammatory condition-triggered protumor inflammation-immunosurveillance shift hydrogel (TRANS) is developed to initiate adaptive immune responses mediated by intercellular communication. Triggered by inflammatory conditions, TRANS releases celecoxib (CXB) to inhibit the COX-2/PGE2 pathway, thereby reprogramming tumor-associated macrophages and mitigating protumor inflammation. Furthermore, TRANS incorporates FMS-like tyrosine kinase 3 ligands (Flt-3L) and 4-1BB agonists (α-CD137) to respectively recruit type 1 conventional DC (cDC1) and revitalize tumor-infiltrating T cells, to rejuvenate immunosurveillance. TRANS inhibits 87.50% and 88.74% of primary and secondary colorectal tumors, generates antitumor immune memory to resist tumor rechallenge, and significantly reduces lung and liver metastases. Rechallenge model shows TRANS leads to antitumor immune memory formation. Single-cell RNA sequencing is preform to elucidate the mechanism of TRANS, which exhibits that TRANS exerts antitumor effects by optimizing the crosstalk between myeloid cells and T cells via CXCL9/10-CXCR3/DPP4. TRANS further gains better control of colorectal cancer when combined with immune checkpoints inhibitors. This study offers a novel perspective on immunotherapy by rebalancing inflammation-immunity dynamics.

Cancer immunoprevention leverages the immune system's surveillance mechanisms to mitigate tumor development. Vaccines that constitute a tumor antigen and an immune adjuvant are perceived as immunoprevention modalities. However, relevant tumor antigens are unknown for non-viral cancers, which constitute most human cancers. Our group has recently shown that SA-4-1BBL, a novel agonist of CD137 receptor, but not antibodies, shows immunoprevention efficacy against various tumors. Advanced bioinformatics analyses of bulk RNA-seq data were conducted to elucidate mechanisms underlying cancer immunoprevention. Mice received subcutaneous injections of SA-4-1BBL or agonistic 3H3 antibody, and the injection-site tissue (IS) and draining lymph nodes (LN) were analyzed for differential gene expression. SA-4-1BBL induced a compartmentalized and temporally dynamic immune program characterized by early effector activation at IS and sustained immune regulation in draining LN. K-means clustering of 4564 DEGs identified eight functionally distinct clusters. IS-enriched clusters contained activation genes for CD4+ T and NK cells, including Cd28, Klra1, Cd4, Cd40, and Cd40l, while LN clusters were enriched for regulatory genes (Tnfaip3, Irf5, Col1a2) that ensure immune priming and homeostatic restraint for a balanced response. SA-4-1BBL generated a more selective and durable activation of adaptive immunity, TCR signaling, Th1/Th2 differentiation, and NK cytotoxicity. 3H3 activated broader innate inflammatory programs, including Toll-like receptor and neurodegeneration-linked pathways. IMPRes analysis showed that SA-4-1BBL activates sequential immune-regulatory circuits centered on Stat1, Cd247, and Ifng and modulates the CD151-TGF-β axis. These findings demonstrate that SA-4-1BBL elicits a balanced immune response, ensuring both safety and efficacy in preventing cancer development.

Early pregnancy loss (EPL) is closely associated with imbalances in the maternal-foetal immune microenvironment. Here we identify CD11c + CD8 + T cells, an unconventional cytotoxic T cell subset, as significantly enriched and activated in EPL cases. These cells contribute to immune dysregulation and inhibit trophoblast invasion through secreting granzyme B, perforin, CD107a, TNF-α, and IFN-γ. Furthermore, we present an effective early prediction model for EPL, based on cytokine and cytotoxic molecule profiles of CD11c + CD8 + T cells in maternal serum, collected 12-16 days post-embryo transfer. Functional assays reveal that IFN-γ triggers trophoblast pyroptosis via the NLRP3/Caspase-1/GSDMD pathway, impairing trophoblast invasion. In vivo validation using abortion-prone mice and an anti-4-1BB antibody-induced model of CD11c + CD8 + T cell activation confirms increased embryo resorption and reduced trophoblast infiltration. These findings highlight the role of dysregulated CD11c + CD8 + T cells at the maternal-foetal interface in EPL, and suggest their potential as biomarkers and therapeutic targets for EPL-management.

Regulatory T cells (Tregs) are known to play critical roles in tissue repair via provision of growth factors, such as amphiregulin (Areg). Areg-producing Tregs have previously been difficult to study because of an inability to isolate live Areg-producing cells. In this report, we created a reporter mouse to detect Areg expression in live cells (AregThy1.1). We employed influenza A and bleomycin models of lung damage to sort Areg-producing and non-Areg-producing Tregs for transcriptomic analyses. Single-cell RNA-Seq revealed distinct subpopulations of Tregs and allowed transcriptomic comparisons of damage-induced populations. Single-cell TCR sequencing showed that Treg clonal expansion was biased toward Areg-producing Tregs and largely occurred within damage-induced subgroups. Gene module analysis revealed functional divergence of Tregs into immunosuppression-oriented and tissue repair-oriented groups, leading to identification of candidate receptors for induction of repair activity in Tregs. We tested these using an ex vivo assay for Treg-mediated tissue repair, identifying 4-1BB agonism as a mechanism for reparative activity induction. Overall, we demonstrate that the AregThy1.1 mouse is a promising tool for investigating tissue repair activity in leukocytes.