AB0132 Increased CD4+CD69+ T Cells and Reduced CD4+CD25+ Treg Cells in Murine Lupus-like Model

Background Proliferation of auto reactive T cells and loss of immunological tolerance are features of SLE. In human lupus, enhanced expression of CD69 in peripheral CD4 T cells indicates incremented activation and lower numbers of CD4 + CD25 + FoxP3 + Treg cells contributes to autoimmunity. Pristane-induced lupus murine model has clinical similarities to human disease, nonetheless whether cellular characteristics of this model resemble those of lupus patients remains unknown. Objectives To analyse the expressions of CD69 activation receptor on CD4 Tcells and of CD4 + CD25 + FoxP3 + Treg cells in peripheral blood and spleen of pristane-induced SLE balb/c mice. Methods Tweenty one female Balb/c mice were analyzed: 13 received a single intraperitoneal 0,5 ml dose of pristane and 8 the same dose of saline. Euthanized mice samples of blood and spleen were collected 120 (T120) days after inoculation of pristane or saline. Mononuclear cells from peripheral blood (PBMC) and splenocytes were obtained by lysis of erythrocytes followed by washings with RPMI medium 1640 and centrifugation, subsequently criopreserved until evaluation by flow cytometry using the appliance GuavaEasyCyteTM HT (Millipore). For this step, cells were unfrozen, washed with RPMI medium 1640 and incubated with monoclonal antibodies against CD3, CD4, CD25, CD28, CD69 and FoxP3 (BD PharmingenTM). The results are expressed as mean ± SD and Mann-Whitney test was used for statistical analysis, being considered significant p Results Compared to control, SLE pristane-induced animals presented increase of CD4+CD69+ T cells in blood and in spleen ( p =0.008 and p =0.049, respectively), while the porcentage of Treg CD4+CD25+FoxP3+ was lower in blood and in spleen ( p =0.012 and p =0.018, respectively). Conclusions Increase of CD4+CD69+ T cell and reduction of CD4+CD25+FoxP3+ Treg expression suggests activated T CD4 cells and loss of peripheral autotolerance in pristane-induced SLE mice. These alterations are similar to observations in human lupus, in indicating that this model may be useful in evaluating mechanisms of cellular activation, peripheral tolerance and homeostatic immune imbalance involved in LES. References Lahita, R. G. Systemic Lupus Erythematosus. Fourth Edition. Toronto: Academic Press; 2004. Mak, A.; Kow, N.Y. Journal of Immunology Research. 2014; Moulton, V.R.; Tsokos, G.C. The Journal of Clinical Investigation. 2015. McGaha, T.L.; Sorrentino, B.; Ravetch, J.V. Science. 2005. Nagarkatti, P. Medical Microbiology. Lecture. 16–17. Abbas, A.K.; Lichtman, A.H.; Pillai, S. Imunologia Basica. 4a edicao. 2013. Doyle, H.A.; Yan, J.; Liang, B.; Mamula, M.J.Immunology Research. 2001. Kuhn, A.; Beissert, S.; Crammer, P.H. Archives of Dermatological Research. 2009. Bonelli, M.; Von Dalwigk, K.; Savitskaya, A.; Smolen, J.S.; Scheinecker, C. Annals of the Rheumatic Diseases. 2008. Bonelli, M.; Von Dalwigk, K.; Savitskaya, A.; Smolen, J.S.; Scheinecker, C. Annals of the Rheumatic Diseases. 2008. Acknowledgement We thank the Division of Rheumatology and the Clinical Emergency, University of Sao Paulo School of Medicine and the State of Sao Paulo Research Foundation (FAPESP). Disclosure of Interest None declared