Participation of plasmacytoid dendritic cells and NKT cells in the mouse model of lupus induced by non-bilayer phospholipid arrangements

Systemic lupus erythematosus (SLE) is a multifactorial autoimmune disease where animal models are used to study its pathogenesis. We have developed a mouse model of an autoimmune disease that resembles human lupus by the injection of liposomes bearing non-bilayer phospholipid arrangements (NPA). We detected the presence of IgG antibodies against NPA in the serum of mice with lupus and patients with SLE. In this work, we determined by citofluorometry the presence of plasmacytoid dendritic cells (pDC) the main producer of type I interferons, and of NKT cells in the secondary lymphoid organs of mice 30 and 60 days after the injection of liposomes with or without NPA induced with 8 mM promazine. In both groups of mice injected with liposomes bearing NPA a significant increase of pDC cells (5-fold) was found which correlates with the high concentration of type I interferon previously detected in this mouse model of lupus and in patients with SLE. A significant increase of NKT (3-fold) was detected at 30 days, specifically in the NKT subpopulation CD4 + that is known to cooperate with B cells in response of lipid antigens; this increase suggests its probable involvement in adaptive immune responses, which lead to the production of anti-NPA IgG antibodies. The increase of pDC and NKT cells found by cytometry in secondary lymphoid organs in this work, suggests their involvement in the formation of anti-NPA IgG antibodies and the development of the disease resembling human lupus.