Comparison of immune cells from germinal centers specific to protein or lipid antigens

Abstract

Anti-lipid IgG antibodies can participate in the physiopathology of some autoimmune diseases. In our research group, we developed a mouse model of Lupus by the administration of liposomes bearing non-bilayer phospholipid arrangements NPA induced by some drugs like chloropromazine CPZ. The mice of this model produce anti-NPA IgG antibodies; these antibodies are mainly formed via germinal center GC. However, the cells that participate in a GC reaction against lipidic antigens are unknown; therefore, we study these cells in the mouse model of Lupus induced by NPA and compared them with a GC reaction against ovalbumin OVA, because the cells that participate in a GC reaction against protein antigens are well known. We studied germinal center B cells, plasma cells, dendritic cells, follicular dendritic cells FDC, T follicular helper cells TFH, T follicular regulatory cells TFR and macrophages from the groups administered with OVA or NPA and compared them with mice without administration. Then we extracted the spleen and the mesenteric lymph nodes and perform flow cytometry and H&E staining at days 5, 10, 15 and 30 postadministration. Histologically, germinal centers were found in both groups at day 5. The mice administered with NPA, present an increase of germinal center B cells 15 days post-administration and a bigger size of the secondary lymphoid organs, the mice administrated with OVA present an increase of these cells and bigger lymph organs at day 10. The higher percentage of plasma cells was found 30 days after the administration of OVA; while dendritic cells and TFH cells presented similar percentages in both groups at all times. For both antigens, the FDC increase at day 5 and 15, the macrophages from day 10 to 15 and the TFR cells increase at day 15.