新型抗胃泌素17疫苗的体液免疫原性与抗原性研究

Humoral immunogenicity and antigenicity of a novel anti-gastrin 17 vaccine

目的:研究一种新型胃泌素17抗原表位结合破伤风类毒素蛋白载体疫苗的体液免疫原性与抗原性,为该疫苗的免疫学药效作用提供参考。方法:疫苗以方案(0.5 mg·只^(-1)×免疫1次·2周^(-1)×免疫3次,i.m)对新西兰大白兔(雌性,n=6)进行免疫,以酶联免疫吸附实验(ELISA)检测免疫开始后第4、6、8周动物血清内Ig G抗体滴度;以竞争性ELISA法检测各类人源蛋白[酰胺化胃泌素17(amidated-G17)、甘氨酸延伸型胃泌素17(gly-G17)、酰胺化胃泌素34(amidated-G34)、血管活性肠肽(VIP)]对疫苗抗体结合抗原的抑制率。结果:免疫开始后第4周所有动物体内均可检测到抗体滴度,第6周抗体滴度达到最大值(P<0.05 vs第4周),第8周抗体滴度恢复至第4周水平(P>0.05 vs第4周);随上述蛋白浓度升高(10-4、10^(-3)、10^(-2)、10^(-1)、100、101、102μmol·L^(-1)),amidated-G17、gly-G17对抗体结合抗原的抑制率均显著升高,其抑制率分别为11.1%、14.8%、20%、26.5%、45%、74.5%、80.8%,11.6%、15.8%、19.1%、25.3%、45.3%、73%、78.2%;而amidated-G34、VIP对抗体结合抗原的抑制率均接近0%。结论:该新型抗胃泌素17疫苗(G17-TT)具有较好的体液免疫原性与抗原性。

Objective： To investigate the humoral immunogenicity and antigenieity of a novel gastrin 17 epitope combined with tetanus toxoid protein carrier vaccine, so as to provide a reference for the immunology therapeutic effects determination. Methods： Six female rabbits were immunized with the vaccine （ 0.5 mg·rabbit^-1 ×2 weeks · injection^-1 × 3 injections, i.m ） and their IgG antibody titers in sera were measured using an enzyme- linked immunosorbent assay at week 4, 6, and 8 after immunization, the inhibition ratio of anti-G17 antibodies binding to antigen by humanized proteins [ amidated gastrin 17 （ amidated-G17 ）, glycine-extend gastrin 17 （ gly-G17 ）, amidated gastrin 34 （ amidated-G34 ）, vasoactive intestinal peptide （ VIP ） ] was detected by a competive ELISA. Results： Following three immunizations, antibodies were detectable at week 4 in all rabbits.The initial surge of antibodies by week 4 was followed by a second surge by week 6 （ P〈0.05 vs week d ）, after which the antibody titers declined and approached the level of week 4 at week 8 （ P〉0.05 vs week 4 ）. With the concentration of competive reagents increasing （ 10^-4, 10^-3, 10^-2, 10^-1, 10^0, 10^1, 10^2 μmol· L^-1 ）, the inhibition ratio of anti-G17 antibodies binding to antigen by amidated-G17, gly-G17 were significantly increased, which was 11.1%, 14.8%, 20%, 26.5%, d5%, 74.5%, 80.8%, and 11.6%, 15.8%, 19.1%, 25.3%, 45.3%, 73%, 78.2% respectively; however, no inhibition effect was observed by amidated-G34 or VIP. Conclusion： This novel anti-gastrin 17 vaccine （ G17-TT ）has good humoral immunogenicity and antigenicity.