Response of different organs of immune system of mice upon administration bacterial CpG DNA

CpG DNA are potent immunostimulator and currently being tested as adjuvant in immunotherapy of various diseases. The aim of this study was to investigate the effects of a single dose of bacterial CpG DNA challenge on response of murine immune system organs and on a zeta-potential of different lymphoid organ cells and peritoneal macrophages in normal and tumor-bearing mice. Metods: Indeces and cellularity of immune organs of mice were evaluated. Z-potential was measured by cellular electrophoresis. Results: Subcutaneous administration of CpG DNA induced local transitory hyperplasia of lymph nodes, moderate increase of splenic index and total spleen cellularity, whereas intraperitoneal injection of CpG DNA caused full-blown spleen enlargement and increase of splenocyte content, and also mice showed transitory aseptic peritonitis. Response of thymus on challenge of CpG DNA was bi-phase: initial phase - response on antigen as stimulus, and late proliferative phase. It was noted that tumor growth does not affect zeta-potential in peritoneal macrophages and mononuclear lymphocytes, but causes increase of zeta-potential on thymocytes and decreases it in lymphocytes from lymph nodes. Furthermore, single administration of CpG DNA normalizes of thymocytes and lymph nodes lymphocytes zeta-potential and increases it in peritoneal macrophages and mononuclear lymphocytes. Conclusion: The findings demonstrate a close correlation between the hyperplasia of lymphoid follicles induced by challenge of CpG DNA and increase of their cellularity. Observed Z-potential alterations of immune system cells after CpG DNA immunization evidence on more significant polyanion accumulation on the surface of splenic macrophages and mononuclear cells.