AB0018 Disease Specific Effects of Lipid Antigens on Vdelta1+ and Vgamma9+ T Cells in Systemic Sclerosis
Authors: I. Bank, H. Migalovich Sheikhet
Journal: Annals of the Rheumatic Diseases (2016)

<h3>Background</h3> T cells (TC) expressing Vδ1+ TC receptors recognize lipids presented by CD1d (1). Oligoclonal Vδ1+ TC infiltrate skin and internal organs and are activated in the peripheral blood (PB) in systemic sclerosis (SSc) suggesting lipids as pathogenic immunogens (2,3). <h3>Objectives</h3> To determine effects and molecular pathways of the auto antigenic lipid – cardiolipin- in SSc and healthy controls (HC). <h3>Methods</h3> Mononuclear cells (MC) were isolated from PB of 12 SSc patients and 8 HC by density centrifugation and cultured in IL2C (RPMI-1640 with 10% fetal bovine serum + 100 international units of interleukin-2), CARDC or OCHC [IL2C+cardiolipin 2.5μg/ml or OCH 50ng/ml (analogue of α-galactosyl ceramide) respectively]. Zoledronate (zol, 2μM), a Vγ9+ γδTC stimulant that induces their CD1d expression, was added to parallel cultures (labeled ILCzol etc.) (4,5). Flow-cytometry (FC) of 4–5 day cultures after staining with monoclonal antibodies (mAb) or CD1d tetramers to detect %CD25+ cells (%CD25+) or tetramer+ cells, was performed.Means were compared by two tailed student t-test; p&lt;0.05 was considered significant. <h3>Results</h3> Vδ1+ and Vγ9+TC consisted 11.85±2.0% and 14.7±3.5% vs 10.42±2.4% and 7.08±1.2% of the CD3+ TC in SSc and HC IL-2C respectively (values not significantly different). In HC cultures, %CD25+ was non significantly different in IL2C, OCHC and CARDC for all TC subsets.Furthermore, IL2Czol increased %CD25+ on all TC subsets relative to IL2C, which was further amplified on Vδ1+ TC in CARDCzol (33.16±7.0% to 56.93±6.3% p&lt;0.007). In SSc, in contrast OCHC and CARDC enhanced %CD25+Vδ1+TC whereas CARDC %CD25+Vγ9+TC was suppressed (76.06±8.7% vs 66.9±10.9%, p&lt;0.036) relative to IL2C. In IL2Czol, however, %CD25+Vγ9+TC increased to 73.93±8.12%. In contrast, IL2Czol decreased SSc %CD25+Vδ1+TC (69.58±8.29% to 55.02±10.54%, p&lt;0.028), but this decrease was partially abrogated in CARDCzol. Both SSc and HC IL2C Vδ1+TC were highly reactive with native and OCH-bound CD1d tetramers (25–70%, n=5 and 50–54% n=2 respectively), but binding was suppressed in SSc samples by zol. In addition, blocking mAb against CD1d abolished the increased expression of CD25 in SSc CARDCzol Vδ1+ TC (from +27±3% to -8.9±2.3%, n=5 p&lt;0.0251) but not in HC (n=2). <h3>Conclusions</h3> Cardiolipin induced suppression of CD25 expression on Vγ9+ TC in SSc, which could be reversed by zol. On the other hand cardiolipin reversed SSc- specific zol induced suppression of CD25 expression on Vδ1+TC in a CD1d dependent-manner. These results suggest that cardiolipin may suppress Vγ9+ TC while augmenting Vδ1+TC activation in SSc, at least in part via CD1d mediated interactions. <h3>References</h3> Luoma, A M.; et al.Immunity 39:6,1032, 2014 Giacomelli, R et al Arth. and Rheum., 41(2), 327,1998. Yurovsky, VV et al., J of Immunol, 153(2), 881,1994. Marcu Malina, V et al., Frontiers in Immunol 5 AN:414, 2014. Schneiders FL, Cancer Immunol Res.;2(8),732,2014 <h3>Acknowledgement</h3> Supported by a donation to I.B. via the Sheba Research Authority <h3>Disclosure of Interest</h3> None declared