Contributions
Abstract: P468
Type: Poster
Abstract Category: Pathology and pathogenesis of MS - 15 Immunology
Background and Objective: CD70, a cytokine that binds CD27, is upregulated on T cells after activation. CD27-CD70 signaling promotes T cell survival and cytokine production. CD70 was identified in a proteomic screen to be associated with MCAM+TH17+ cells and could be involved in TH1 differentiation.
In multiple sclerosis (MS) autoimmune TH1 and TH17 cells are able to infiltrate the central nervous system; therefore our goal is to investigate if CD70 expression is important for this T cell pathogenicity and migration.
Methodology and Results: We confirmed by flow cytometry (FC) that CD70 is present, albeit low (0,5-1% of T cells), on ex vivo T cells from peripheral blood (PB) of healthy donors (HD). Next, we found that CD70+ T cells produce significantly higher amounts of IL17 and IFNγ compared to CD70- T cells. In addition, in vitro activation of T cells with various cytokines shows that CD70 is significantly upregulated in the presence of TGFβ1 and TGFβ3. This upregulation is accompanied by an increased amount of IFNγ, IL17, GMCSF producing and MCAM expressing CD70+ T cells. Furthermore, RT-PCR and FC showed that CD70 is significantly higher expressed on TH1 and TH17 cells compared to TH2 cells. When adding TGFβ to these polarization conditions the proportion of CD70+ cells increased together with an increase in pro-inflammatory cytokine (IFNγ, IL17 and GMCSF) producing CD70+ TH1 and TH17 cells.
In untreated MS patients, the percentage of ex vivo CD70+ T cells in the PB is significantly higher compared to HD. In addition, stimulation with TGFβ leads to a significantly higher increase of CD70 and a higher percentage of IFNγ and IL17 producing CD70+ T cells in MS compared to this increase seen in HD. TH1 and TH17 cells from untreated MS patients show a higher expression of CD70 compared to TH2 cells, as HC. However, preliminary RT-PCR data shows that TH17 cells from MS patients express more CD70 compared to TH1.
CD70+ T cells were found in white matter and cortical lesions of MS brains by performing FC on lesions cut out of fresh MS brain. Interestingly, the percentage of CD70+ T cells is much higher in the lesions compared to PB (respectively 20% vs 2-3%).
Conclusions: CD70 expression, upregulated by TGFβ1 and TGFβ3, discriminates a highly active and pro-inflammatory subset of TH1 and TH17 cells. The expression and pro-inflammatory nature of CD70 in ex vivo, polarized or TGFβ stimulated T cells is higher in MS patients compared to HD.
Disclosure: Tessa Dhaeze is funded by the FRQS for this project.
Laurence Tremblay is funded by the Université de Montréal for this project.
All the other authors have nothing to disclose for this project.
Abstract: P468
Type: Poster
Abstract Category: Pathology and pathogenesis of MS - 15 Immunology
Background and Objective: CD70, a cytokine that binds CD27, is upregulated on T cells after activation. CD27-CD70 signaling promotes T cell survival and cytokine production. CD70 was identified in a proteomic screen to be associated with MCAM+TH17+ cells and could be involved in TH1 differentiation.
In multiple sclerosis (MS) autoimmune TH1 and TH17 cells are able to infiltrate the central nervous system; therefore our goal is to investigate if CD70 expression is important for this T cell pathogenicity and migration.
Methodology and Results: We confirmed by flow cytometry (FC) that CD70 is present, albeit low (0,5-1% of T cells), on ex vivo T cells from peripheral blood (PB) of healthy donors (HD). Next, we found that CD70+ T cells produce significantly higher amounts of IL17 and IFNγ compared to CD70- T cells. In addition, in vitro activation of T cells with various cytokines shows that CD70 is significantly upregulated in the presence of TGFβ1 and TGFβ3. This upregulation is accompanied by an increased amount of IFNγ, IL17, GMCSF producing and MCAM expressing CD70+ T cells. Furthermore, RT-PCR and FC showed that CD70 is significantly higher expressed on TH1 and TH17 cells compared to TH2 cells. When adding TGFβ to these polarization conditions the proportion of CD70+ cells increased together with an increase in pro-inflammatory cytokine (IFNγ, IL17 and GMCSF) producing CD70+ TH1 and TH17 cells.
In untreated MS patients, the percentage of ex vivo CD70+ T cells in the PB is significantly higher compared to HD. In addition, stimulation with TGFβ leads to a significantly higher increase of CD70 and a higher percentage of IFNγ and IL17 producing CD70+ T cells in MS compared to this increase seen in HD. TH1 and TH17 cells from untreated MS patients show a higher expression of CD70 compared to TH2 cells, as HC. However, preliminary RT-PCR data shows that TH17 cells from MS patients express more CD70 compared to TH1.
CD70+ T cells were found in white matter and cortical lesions of MS brains by performing FC on lesions cut out of fresh MS brain. Interestingly, the percentage of CD70+ T cells is much higher in the lesions compared to PB (respectively 20% vs 2-3%).
Conclusions: CD70 expression, upregulated by TGFβ1 and TGFβ3, discriminates a highly active and pro-inflammatory subset of TH1 and TH17 cells. The expression and pro-inflammatory nature of CD70 in ex vivo, polarized or TGFβ stimulated T cells is higher in MS patients compared to HD.
Disclosure: Tessa Dhaeze is funded by the FRQS for this project.
Laurence Tremblay is funded by the Université de Montréal for this project.
All the other authors have nothing to disclose for this project.