Effect of urate monosodium crystals on gamma/delta T cells

SABBIONE, FLORENCIA; ANALÍA, TREVANI S.; TOWSTYKA, NADIA YASMÍN; GEFFNER, JORGE R.; KEITELMAN, IRENE; JANCIC, CAROLINA CRISTINA

Mar del Plata

Congreso; 64 Reunión Anual de la Sociedad Argentina de Inmunología; 2016

Uric acid is released from dying cells and functions as an adjuvant that promotes the generation of adaptive immune responses.The inflammatory effect of uric acid depends on its precipitation into monosodium urate crystals (MSUC). MSUC activate differentintracellular pathways, i.e. Syk kinase and PI3K. Gamma/delta T cells act as sensors of cellular stress and infection. They recognize danger and pathogen-associated molecular patters, such as phosphoantigens. We have previously reported that MSUC activategamma/delta T cells. Now, we aim to investigate whether MSUC modulate gamma/delta T cell activation triggered by phosphoantigens, and the mechanism involved in gamma/delta T cell activation by MSUC. Gamma/delta T cells were purified from human peripheralblood by using an anti-TCR gamma/delta MicroBead isolation kit. After purification, gamma/delta T cells were incubated or not with MSUC (200 ug/ml, 48 h). Then, we analyzed CD69 expression by flow cytometry, and IFN-gamma and TNF-alpha production by ELISA. To investigate the co-stimulatory effect of MSUC, we treated gamma/delta T cells with the phosphoantigen HMBPP (10 uM) and then we incubated cells with MSUC. Finally, to study the mechanism involved in gamma/delta T cell activation by MSUC, we treated cells with or without a protein kinase Syk inhibitor, GS-9973 (0.1 uM Gamma/delta T cells co-stimulated with MSUC and HMBPP produced higher levels of IFN-gamma and TNF-alpha compared to gamma/delta T cells activated by MSUC or HMBPP alone (p<0.05, n=13). On the other hand, treatment of gamma/delta T cells with Syk inhibitor GS-9973, completely abrogated the increase in CD69 expression induced by MSUC (p<0.05, n=7).  Our results indicate that gamma/delta T cells activated with HMBPP are able to recognize MSUC efficiently, suggesting a possibly role in sensing cell death molecular patterns released during an infection. Also, we show that the protein kinase Syk is involved in gamma/delta T cells activation by MSUC.