CONICET | Buscador de Institutos y Recursos Humanos

Background: Gamma/delta T cells play a critical role in the recruitment andactivation of neutrophils at the sites of infection, in addition, neutrophilscan regulate gamma/delta T cell activity. We havepreviously reported that neutrophils regulate gamma/delta T cell activation induced by anti-CD3 antibodies and thisprocess was independent on caspase-1 activation. Now, we aim to investigate therole of leukocyte serine-proteases during this process, since it is known that theseproteases can induce the activation of conventional T cells. Methods: gamma/delta T cells were purified from human peripheral bloodmononuclear cells, by using an anti-TCR gamma/delta MicroBeadisolation kit. Neutrophils were isolated by dextran sedimentation. Afterpurification, gamma/delta T cells were stimulated with anti-CD3 antibodies (250ng/ml, 60 min), and then were cultured with or without neutrophils. After 24hours, we analyzed the CD69 expression and IFN-gamma production by gamma/delta Tcells by flow cytometry and ELISA, respectively. We evaluated the secretion ofelastase by neutrophils using a specific substrate and spectrophotometryanalysis. Results: Treatment of neutrophils with the serine-proteases inhibitor, AEBSF completelyabrogated the up-regulation of CD69 expression (p<0.001, n=4) and the production of IFN-gamma (p<0.001,n=6) in gamma/delta Tcell. In presence of activated gd Tcell, neutrophils increased the secretion of elastase to the co-culture medium(p<0.05, n=3). Conclusion: Our results indicate that serine-proteases secreted by neutrophilsmay mediate the potentiation of gamma/delta T cell activation. We are currently investigating therole of elastase, cathepsin G and proteinase 3, on the activation of gamma/delta T cell.