Immune responses induced by BCG prime and single dose of recombinant adenovirus Ad5-CEAB boosted strategy in mice / 中国人兽共患病学报

ABSTRACT

Tuberculosis (TB) remains an enormous health burden worldwide.To date,Mycobacterium bovis Bacillus Calmette Guerin (BCG) is the unique anti-TB vaccine available for humans,which provides an important but limited protection from the Mycobacterium tuberculosis (Mtb) infection.It is therefore an urgent need to develop better vaccines and vaccination strategies to prevent the spread of Mtb infection.Heterologous prime-boost vaccination strategies using both BCG and novel anti-TB vaccines have been demonstrated to induce robust immune responses than BCG alone.We have previously demonstrated that a recombinant adenoviral vector Ad5-CEAB co-expressing CFP10,ESAT6,Ag85A and Ag85B of Mtb was able to induce robust antigen-specific immune responses in mice.In the present study,we examined immunological effects of Ad5-CEAB in the mice primed with BCG and boosted with a single dose of the virus via an intranasal route.Results demonstrated that this vaccination strategy could effectively induce strong antigen-specific mucosal and humoral immune responses.These immune responses were characterized with an increased productions of cytokines (IL-12 and IFN-γ),increased concentration of secretary IgA (sIgA) in bronchoalveolar lavage fluid (BALF) and serum IgG in mice in comparison with mice in BCG group.These data suggested that the regimen of BCG prime-single dose of Ad5-CEAB boosted strategy was novel for inducing antigen-specific immune responses in response to Mtb antigens in vivo,which warrants for further development of adenoviral-based vaccine against Mtb infection.