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

there is general agreement that effective mucosal vaccines (oral, nasal, sublingual, and genital tract vaccines) could dramatically stimulate protective immune responses not only against mucosal infections but also against HIV, Mycobacterium tuberculosis, and many other pathogens [8, 37] . In this study, we compared the capability of Ad-UMAS to induce systemic humoral and cellular immune responses, and local mucosal immune responses via five vaccination pathways (i.m., i.v., s.c., i.o., and i.n.). Mucosal vaccines are advantageous compared with systemic vaccines from a production and regulatory perspective [18, 23] . Previous studies have revealed that a Middle East respiratory syndrome (MERS) vaccine greatly enhances local mucosal immune responses in immunized BALB/c mice with the intranasal inoculation method [24] . Ideal attenuated vaccines could be engineered to have a limited capacity for replication and to deliver an effective antigen, while avoiding unwanted inflammatory responses [35, 39, 41] . Recombinant adenoviruses are some of the most intensively investigated vaccine carriers in many pathogenic infections, such as Ebola virus, HIV, and the malaria parasite [1, 11, 16, 32] . Several clinical trials have shown that vaccines based on adenoviruses could elicit vigorous and sustained T-cell responses, with the advantage of safety and high immunogenicity [25] .