Novel CpG oligodeoxynucleotide adjuvant enhances the immune response of inactivated human adenovirus-55 antigen in BALB/c mice
10.3760/cma.j.cn112866-20220322-00064
- VernacularTitle:新型CpG-ODN佐剂增强灭活HAdV-55抗原在BALB/c小鼠体内的免疫应答
- Author:
Yi FENG
1
;
Jie JIANG
;
Ying LIU
;
Ruoqun MA
;
Jianlin CAI
;
Lei CAO
;
Hai LI
;
Hu REN
;
Zhen ZHU
;
Aili CUI
;
Yan ZHANG
;
Wenbo XU
;
Naiying MAO
Author Information
1. 中国疾病预防控制中心病毒病预防控制所，北京 102206
- Keywords:
HAdV-55;
Immunogenicity;
CpG-ODN
- From:
Chinese Journal of Experimental and Clinical Virology
2022;36(4):409-416
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To evaluate the effect of synthetic CpG oligodeoxynucleotide (CpG-ODN) as adjuvant on immune response induced by inactivated human adenovirus (HAdV)-55 antigen in BALB/c mice.Methods:HAdV-55 virus QS prototype strain was purified by plaque to construct a seed bank of vaccine candidate strain. The amplified product of vaccine candidate strain was inactivated by 0.05%β-propiolactone, and purified to prepare perfect virus particle antigen. The purified HAdV-55 antigen was mixed with the same volume CPG-ODN and aluminum hydroxide adjuvant in low-dose group (0.2 mg/ml) and high-dose group (1 mg/ml), respectively, and inoculated BALB/c mice after emulsification. Meanwhile, the control group was set with PBS, and the immunization was enhanced once every 21 days. Respectively on primary immune 21 and 35 days after collecting venous blood in mice and separation of serum, serum was collected at the end of the time of separating spleen lymphocytes in mice. The levels of HAdV-55 specific IgG antibody and neutralization antibody in serum of immunized mice were observed by ELISA and micro-neutralization test, and the levels of lymphocytes secreting IL-4 and IFN-γ cytokines were detected by ELISpot.Results:No matter with or without adjuvant, along with the increase of the number of immunization and vaccination dose of inactivated HAdV-55 antigen induced BALB/c mice virus specific IgG antibody was also significantly increased. However, neutralizing antibody can reach detectable level only after enhanced immunity, and the geometric mean titer (GMT) of neutralizing antibody is between 1: 11 and 1: 23. Different adjuvants have significant effects on the immune response of mice. Low dose antigen combined with CPG-ODN and aluminum hydroxide mixed adjuvant can induce higher humoral and cellular immune responses in mice, and the levels of specific IgG antibody and neutralizing antibody are 2.2 and 1.8 times higher than those in the aluminum hydroxide adjuvant group, respectively. The number of lymphocytes secreting IFN-γ was 2.3 times that of the group immunized with aluminum hydroxide adjuvant.Conclusions:The novel CPG-ODN adjuvant significantly increased the immunogenicity of the inactivated HAdV-55 whole virus antigen in BALB/c mice and directed the cellular immune response toward Th1 type.
