Vaccination with recombinant adenovirus expressing multi-stage antigens of Toxoplasma gondii by the mucosal route induces higher systemic cellular and local mucosal immune responses than with other vaccination routes

Wang, Ting; Yin, Huiquan; Li, Yan; Zhao, Lingxiao; Sun, Xiahui; Cong, Hua

The memory T-cell consists of CD4 + and CD8 + T-cells, which play a vital role in the establishment of protective immunity in hosts [31] . CD8 + T-cells can control the spreading and development of T. gondii infection in synergy with CD4 + T-cells [12] . In our study, CD4 + and CD8 + T lymphocyte subsets from immunized mice were assayed by flow cytometry. There was a marked increase in the percentage of CD8 + T-cells in mice immunized with the Ad-UMAS vaccine via mucosal routes. Cytokines play a critical role in the activities of Th cells. As we know, Th1 cells are responsible for limiting tissue extension of the parasite through the production of IL-2 and IFN-c [15] . Our results show that in contrast with the blank control, high levels of IL-2 and IFN-c were induced in mice immunization with Ad-UMAS especially treated intraorally and intranasally. However, there is no difference in IL-10 production between vaccinated and control groups. Additionally, splenocyte proliferation activity was significantly enhanced in mice immunized via oral and nasal routes. These results clearly suggest that mucosal vaccination with Ad-UMAS can significantly augment Th1-mediated cellular immune responses in which CD8 + T lymphocytes are considered as major effectors responsible for controlling parasite infection and secreting IFN-c during the cellular response against toxoplasmosis.