CpG adjuvant enhances the mucosal immunogenicity and efficacy of a Treponema pallidum DNA vaccine in rabbits

• Published in: Human vaccines & immunotherapeutics 2013-04, Vol.9 (4), p.753-760
• Main Authors: Zhao, Feijun, Liu, Shuangquan, Zhang, Xiaohong, Yu, Jian, Zeng, Tiebing, Gu, Weiming, Cao, Xunyu, Chen, Xi, Wu, Yimou
• Format: Article
• Language: English
• Subjects: Adjuvants, Immunologic - administration & dosage; Administration, Intranasal; Animals; Antibodies, Bacterial - blood; Bacterial Vaccines - administration & dosage; Bacterial Vaccines - genetics; Bacterial Vaccines - immunology; Cell Proliferation; CpG ODN; Cytokines - secretion; Disease Models, Animal; DNA vaccine; Female; Humans; Immunoglobulin A, Secretory - blood; Injections, Intramuscular; Leukocytes, Mononuclear - immunology; membrane protein; mucosal adjuvant; mucosal immune; Oligodeoxyribonucleotides - administration & dosage; Rabbits; Research Paper; Syphilis - immunology; Syphilis - prevention & control; Tp Gpd; Treponema pallidum; Treponema pallidum - genetics; Treponema pallidum - immunology; Vaccination - methods; Vaccines, DNA - administration & dosage; Vaccines, DNA - genetics; Vaccines, DNA - immunology
• ISSN: 2164-5515; 2164-554X
• DOI: 10.4161/hv.23064

Objectives: The protective response against Treponema pallidum (Tp) infection of a DNA vaccine enhanced by an adjuvant CpG ODN was investigated. Results: The mucosal adjuvant CpG ODN enhanced the production of higher levels of anti-TpGpd antibodies induced by pcD/Gpd-IL-2 in rabbits. It also resulted in higher levels of secretion of IL-2 and IFN-γ, and facilitated T cell proliferation and differentiation (p < 0.05). No significant difference about testing index above-mentioned was found in the intranasal immunization group of pcD/Gpd-IL-2 vaccine adjuvanted by CpG ODN when compared with the immunization by pcD/Gpd-IL-2 vaccine intramuscular injection alone (p > 0.05). Furthermore, CpG ODN stimulated the production of mucosa-specific anti-sIgA antibodies and resulted in the lowest Tp-positive rate (6.7%) for Tp-infection of skin lesions and the lowest rates (8.3%) of ulceration lesions, thus achieving better protective effects. Methods: New Zealand rabbits were immunized with the eukaryotic vector encoding recombinant pcD/Gpd-IL-2 using intramuscular multi-injection or together with mucosal enhancement via a nasal route. The effect of the mucosal adjuvant CpG ODN was examined. Conclusions:The CpG ODN adjuvant significantly enhances the humoral and cellular immune effects of the immunization by pcD/Gpd-IL-2 with mucosal enhancement via nasal route. It also stimulates strong mucosal immune effects, thus initiating more efficient immune-protective effects.