新型抗胃泌素17疫苗的体液免疫原性与抗原性研究

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IgG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<0.05vs第4周),第8周抗体滴度恢复至第4周水平(P>0.05vs第4周);随上述蛋白浓度升高(10^-4、10^-3、10^-2、10^-1、10⁰、10¹、10² μmol·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 antigenicity 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 enzymelinked 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 4),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^-1,10⁰,10¹,10² 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%,45%,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.