Expression of cell surface molecules, CD80, CD83, CD86, CCR7 and MHC class II, on CD11c+ cells in cervical lymph nodes from mice immunized with PEI/pci-S complexes. BALB/c mice were immunized with PBS, pci-mock, pci-S, or PEI/pci-S complexes and then cell surface molecules on CD11c+ cells from cervical lymph nodes were analyzed on day 3 after the last immunization. (A) The expressions of major cell surface molecules, CD80, CD83, CD86, CCR7, and MHC class II (I-Ad) on CD11c+ DC were determined by flow cytometry. Data were expressed as the mean value of mean fluorescence intensity ± SD. Significant differences compared with pci-S group were expressed as *P < 0.05. (B) Expression of MHC class II molecules was represented by histogram.