2022 Annual Meeting and Alumni Reunion
Category : Clinical Research Candidate : Aastha Singh Poster #: C14
Mesenchymal Stem Cells-derived Interleukin-11 Inhibits Activation and Proliferation of T cells
Aastha Singh , Sharad Mittal , WonKyung Cho , Yilin Guan , Elsayed Elbasiony , Sunil Chauhan
Purpose : Uncontrolled T cell activation can result pathological conditions including autoimmunity and graft rejections . Our group has previously shown that mesenchymal stem cells ( MSCs ) inhibit activation of innate immune cells including neutrophils and macrophages . Here , we investigate whether MSCs regulate T cell responses by secreting interleukin-11 ( IL-11 ).
Methods : Human bone-marrow derived MSCs ( hMSCs ) were purchased and phenotypically characterized for their expression of CD45- CD34- CD73 + CD90 +. CD4 + CD25- T cells ( purity : > 95 %) were magnetically sorted from human peripheral blood mononuclear cells for the MSC-T cell co-culture assays . Expression and secretion of IL-11 by hMSCs were evaluated using real-time PCR and ELISA , respectively . Expression of IL-11 receptor was confirmed in activated CD4 + CD25- T cells using flow cytometry . CD4 + CD25- T cells stimulated with anti-CD3 / CD28 beads ( 1:1 ratio ) were co-cultured with MSCs at 1:1 ratio for 24 hours ( for early activation ) and 66 hours ( for proliferation ) in the presence and absence of hIL-11 neutralizing antibody ( 20 µ g / ml ). Early T cell activation was assessed by evaluating expression of CD40L and CD69 ( Median Fluorescence intensity ; MFI ) using flow cytometry . For proliferation , CD4 + CD25- T cells were stained with CFSE prior to co-culture and their proliferation was quantified by measuring CFSE dilution via flow cytometry .
Results : hMSCs constitutively express high levels of IL-11 at both mRNA and protein levels . Naïve CD4 + CD25- T cells showed the expression of IL-11 receptor , which was upregulated by 2-fold following CD3 / CD28 stimulation . hMSCs significantly suppressed early activation of naive T cells , as indicated by an approximate 70 % reduction in expression of both CD69 ( p = 0.025 ) and CD40L ( p = 0.011 ). This MSC mediated reduction in early T cell activation was not observed following the neutralization of IL-11 . Furthermore , our CFSE dilution assay demonstrated that hMSCs significantly prevented the proliferation of CD4 + CD25 T cells ( p = 0.006 ); however , this MSC-mediated suppression of proliferation was abrogated following IL-11 neutralization .
Conclusions : IL-11 secretion by human mesenchymal stem cells is critical for inhibition of early T cell activation and proliferation .