Targeting antigen to B cells and dendritic cells via direct conjugation to anti-CD180 antibody promotes robust antigen-specific antibody responses in the absence of adjuvant.

CD180 is homologous to TLR4 and regulates TLR4 signaling, yet its function is unclear. We report that injection of anti-CD180 mAb into mice induced rapid Ig production of all classes and subclasses except IgA and IgG2b, with up to 50-fold increases of serum IgG1 and IgG3. IgG production after anti-CD180 injection was not due to reactivation of memory B cells and was retained in T cell-deficient (TCR KO), CD40 KO, IL-4 KO and MyD88 KO mice. Anti-CD180 rapidly increased both transitional and mature B cells, with especially robust increases in transitional B cell number, MZ B cell proliferation, and CD86 but not CD80 expression. In contrast, anti-CD40 induced primarily FO B cell and myeloid expansion with increases in expression of CD80 and CD95 but not CD86. The expansion of splenic B cells was due in part to proliferation and occurred in WT and TCR KO mice whereas T cell expansion occurred in WT but not in B cell-deficient (μMT) mice, indicating a direct role for B cells in CD180 stimulation in vivo. Combinations of anti-CD180 with various MyD88-dependent TLR ligands biased B cell fate as co-injection diminished Ig production but purified B cells exhibited synergistic proliferation. Anti-CD180 had no effect on cytokine production from B cells but increased IL-6, IL-10, and TNF-α production in combination with LPS or CpG. Thus CD180 stimulation induces intrinsic B cell proliferation and differentiation, causing rapid increases in IgG, and integrates MyD88-dependent TLR signals to regulate proliferation, cytokine production, and differentiation.

Type 1 diabetes is an autoimmune disease in which insulin-secreting β-cells are destroyed, leading to a life-long dependency on exogenous insulin. There are no approved disease-modifying therapies available, and future immunotherapies would need to avoid generalized immune suppression. We developed a novel plasmid expressing preproinsulin2 and a combination of immune-modulatory cytokines (transforming growth factor-beta-1, interleukin [IL] 10 and IL-2) capable of near-complete prevention of autoimmune diabetes in non-obese diabetic mice. Efficacy depended on preproinsulin2, suggesting antigen-specific tolerization, and on the cytokine combination encoded. Diabetes suppression was achieved following either intramuscular or subcutaneous injections. Intramuscular plasmid treatment promoted increased peripheral levels of endogenous IL-10 and modulated myeloid cell types without inducing global immunosuppression. To prepare for first-in-human studies, the plasmid was modified to allow for selection without the use of antibiotic resistance; this modification had no impact on efficacy. This pre-clinical study demonstrates that this multi-component, plasmid-based antigen-specific immunotherapy holds potential for inducing self-tolerance in persons at risk of developing type 1 diabetes. Importantly, the study also informs on relevant cytokine and immune cell biomarkers that may facilitate clinical trials. This therapy is currently being tested for safety and tolerability in a phase 1 trial (ClinicalTrials.gov Identifier: NCT04279613).

Type 1 diabetes is an autoimmune disease in which insulin-secreting β-cells are destroyed, leading to a life-long dependency on exogenous insulin. There are no approved disease-modifying therapies available, and future immunotherapies would need to avoid generalized immune suppression. We developed a novel plasmid expressing preproinsulin2 and a combination of immune-modulatory cytokines (transforming growth factor-beta-1, interleukin [IL] 10 and IL-2) capable of near-complete prevention of autoimmune diabetes in non-obese diabetic mice. Efficacy depended on preproinsulin2, suggesting antigen-specific tolerization, and on the cytokine combination encoded. Diabetes suppression was achieved following either intramuscular or subcutaneous injections. Intramuscular plasmid treatment promoted increased peripheral levels of endogenous IL-10 and modulated myeloid cell types without inducing global immunosuppression. To prepare for first-in-human studies, the plasmid was modified to allow for selection without the use of antibiotic resistance; this modification had no impact on efficacy. This pre-clinical study demonstrates that this multi-component, plasmid-based antigen-specific immunotherapy holds potential for inducing self-tolerance in persons at risk of developing type 1 diabetes. Importantly, the study also informs on relevant cytokine and immune cell biomarkers that may facilitate clinical trials. This therapy is currently being tested for safety and tolerability in a phase 1 trial (ClinicalTrials.gov Identifier: NCT04279613).