The levels of local and systemic antibodies specific to the Apx antigens were investigated in mice orally immunized with Apx antigen-expressing yeast. Specific IgA responses to ApxIA or ApxIIA in the intestines and lungs from mice immunized with yeast expressing Apx antigens were significantly higher than those in the control groups after the second and third immunizations, respectively (p < 0.05). All mice were monitored for up to 72 h after challenge with the MLD of an A. pleuropneumoniae field isolate. Overall, the final survival rates of the vaccinated groups were higher than those of the control groups at each time point (Shin et al., 2007).
Shin et al., 2007: Shin SJ, Shin SW, Kang ML, Lee DY, Yang MS, Jang YS, Yoo HS. Enhancement of protective immune responses by oral vaccination with Saccharomyces cerevisiae expressing recombinant Actinobacillus pleuropneumoniae ApxIA or ApxIIA in mice. Journal of veterinary science. 2007; 8(4); 383-392. [PubMed: 17993753].
