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

Adenovirus, which can penetrate host cells delivering vaccine antigen to antigen-presenting cells (APCs) and elicit vigorous and sustained T-cell responses, is a promising T. gondii vaccine vector and can be used effectively to transport immunogens [27] . Recent studies have also found that recombinant canine adenovirus type-2 expressing TgROP16 and TgROP18 provides partial protection against acute T. gondii infection in mice, and indicate that adenovirus vectors may be potentially useful in the development of an effective vaccine against T. gondii infection [21, 22] . The mucosal immune system consisting of specialized epithelial cells can trigger both humoral and cell immune responses when antigens are administered with appropriate adjuvants or attenuated live vaccines via mucosal routes (oral, nasal, sublingual, ocular, genital, or rectal) [18, 23] . Furthermore, local mucosal immunization can lead to antigen-specific T-and B-cell responses not only in mucosal sites but also systemically [5, 24] . Hence, there is a greater need for effective vaccines that exert protective effects at mucosal surfaces, especially for intracellular parasites such as T. gondii.