Abstract: OBJECTIVE:To analyze the suptype and activity of spleen immune cells in apolipoprotein CⅢ (Apo C3) transgenic mice. METHODS:Using ICR Apo C3 transgenic mice as a research model,weights of transgenic and wild-type mice were measured and blood samples were collected from the posterior venous plexus of mice. The triglyceride assay kit was used to determine plasma triglyceride levels by enzyme reaction colorimetric method in a microplate reader. Mice with a plasma triglyceride level of ≥ 1 000 mg/dL (11.3 mmol/L) were selected for supsequent experiments. The spleens of these mice were prepared into single cell suspensions. The frequencies and suptypes of various immune cells in the spleen of the transgenic and wild-type mice were detected by flow cytometry using cell membrane surface molecules, intracellular molecules and intranuclear molecular staining. Then,the spleen cells of transgenic and wild-type mice were co-cultured with colon cancer cell MC38 in 1:1,3:1,3:1 ratios for 72 h,and expressions of CD107a in CD8⁺ T cells were determined. RESULTS: Plasma triglyceride levels were elevated in the transgenic mice but there was no significant difference in body weight compared to wild-type mice. Furthermore,the frequencies of CD3⁺CD8⁺ and CD3⁺CD8⁺ NKG2D⁺ cells in spleen of the transgenic mice were increased significantly;of myeloid-derived suppressor cells MDSC) were increased;of spleen NK cells was,however,significantly reduced; of CD3⁺CD4⁺NKG2D⁺,CD3⁺ CD4⁺IL^-17⁺ cells in spleens and of regulatory T cells,NKT cells,γδT cells,B cells and macrophages did not changed significantly. The frequencies of CD8⁺CD62L^-CD44⁺ and CD8⁺CD44⁺KLGR1⁺ in Apo C3 transgenic mice were increased, effector T cells mainly, and the secretions of IFN-γ by CD8 ⁺ T cells were enhanced. The expressions of CD107a in CD8⁺ T cells were increased in transgenic mice. CONCLUSION:Plasma triglyceride levels were significantly increased in Apo C3 transgenic mice. Compared with wild-type mice,the frequencies and activities of CD8 + T cells were up-regulated in transgenic mice, the frequencies of myeloid suppressor cells were increased,and that of NK cells were decreased. Moreover,the ability of CD8⁺T lymphocytes to kill target cells in transgenic mice was enhanced.

Key words: Apo C3, transgenic mice, immune cells, triglyceride