Session Name: B-cell / Antibody /Autoimmunity
Session Date & Time: None. Available on demand.
*Purpose: Our team previous study showed that TLR-Bregs, stimulated through TLR pathway in vitro, harbored regulatory properties by suppressing CD4+ T cell proliferation and function in vitro and in vivo. These TLR-Bregs can also prolong skin graft survival. We describe here to explore TLR-Bregs function to induce Tregs and identify the mechanism of Tregs induction by TLR-Bregs.
*Methods: OB1 TLR-Bregs were generated in vitro from B cells isolated from transgenic OB1 mice (B cell receptor specific to OVA). For Tregs induction by TLR-Bregs assay, C57BL/6 mice, transplanted with OVA skin, treated with or without OB1 TLR-Bregs. The CD4+Foxp3+ Tregs expression in draining lymph node (DLN) of recipient will be detected at day 14. To identify the mechanism of OB1 TLR-Bregs on Tregs induction, CD4+CD25– T cells sorted from OT II mice spleen, and then adoptively transfer to the SCID mice underwent OVA skin graft. In the same line, the SCID mice would be administrated OB1 TLR-Bregs (BCR specific for OVA) alone or combine with anti-IL-10 antibody (250 ug/mice), anti-TGF-β antibody (200ug/mice) or isotype control (200ug/mice) every other day from day 0 to day 8. After 14 days, CD4+CD25+Foxp3+ Tregs from DLN would be analyzed by flow cytometry.
*Results: The results from Tregs induction by TLR-Bregs assay showed that, with OB1 TLR-Bregs treatment, the CD4+Foxp3+ Tregs expression is highly increased (p<0.05, vs control). The experiment of Tregs generation in SCID mice revealed significant upregulation in CD4+CD25+Foxp3+ Tregs expression with OB1 TLR-Bregs treatment (3.7%±1.6%, p<0.05, vs no B cells). In the same time, when SCID mice administrated with the combination of OB1 TLR-Bregs and anti-TGF-β antibody, CD4+CD25+Foxp3+ Tregs expression would be decreased significantly (1.6%±o.4%, p<0.05, vs OB1 TLR-B cells). However, depletion of IL-10 in mice treated with OB1 TLR-Bregs showed no big difference with OB1 TLR-Bregs alone.
*Conclusions: OBI TLR-Bregs can convert the CD4+CD25– T cells to CD4+CD25+Foxp3+ Tregs, and only the ablation of the TGF-β antibody block Tregs induction, that attributes to TLR-Breg cells induce Foxp3 expression of CD4+CD25– T cells through TGF-β but not IL-10. Tregs induced by TLR-Bregs is related to prolong the skin graft survival. Therefore, TGF-β dependent tolerance induction by TLR-Bregs will be explored in organ transplantation model.
To cite this abstract in AMA style:Huai G, Lee K, Deng K, Fu Q, Rickert CG, Deng S, LeGuern C, Markmann JF. In Vitro Generated Regulatory B Cells Induce Cd4+Cd25+Foxp3+Tregs from Cd4+Cd25–T Cells via TGF-β [abstract]. Am J Transplant. 2021; 21 (suppl 3). https://atcmeetingabstracts.com/abstract/in-vitro-generated-regulatory-b-cells-induce-cd4cd25foxp3tregs-from-cd4cd25-t-cells-via-tgf-%ce%b2/. Accessed June 20, 2021.
« Back to 2021 American Transplant Congress