Institute of Biomedicine, University of Turku, Turku, Finland.
Statens Serum Institut, Copenhagen, Denmark.
Emerg Microbes Infect. 2023 Dec;12(1):e2174782. doi: 10.1080/22221751.2023.2174782.
Pertussis toxin (PT) is a unique virulence factor of , and therefore a key component of acellular pertussis vaccines. Although immunity after infection seems to persist longer than after vaccination, the exact mechanisms are not fully known. In this study the overall binding strength (avidity) of anti-PT IgG antibodies was compared after acellular booster vaccination and infection, as a parameter to evaluate long-lasting protection.Danish and Finnish serum samples from a total of 134 serologically confirmed patients and 112 children who received acellular booster vaccines were included in this study. The concentration of anti-PT IgG was first determined by ELISA, followed by two separate ELISAs to evaluate antibody avidity: either with a dilution series of urea as a bond-breaking agent of antibody and antigen binding and a constant anti-PT IgG concentration between the samples or with a constant dilution ratio of sera and detergent. In addition to urea, the use of diethylamine and ammonium thiocyanate as disruptive agents were first compared between each other.A strong Spearman correlation ( > 0.801) was noted between avidity and concentration of anti-PT IgG antibodies if a constant serum dilution method was used, and avidity was noted to be higher in patients in comparison to vaccinees in Denmark, but not in Finland. However, no correlation between antibody concentration and avidity was found if a constant anti-PT IgG concentration was used ( = -0.157). With this method, avidity after vaccination was significantly higher in comparison to that after infection in both Danish and Finnish subjects ( < 0.01). A shorter time since the latest booster vaccination was found to affect avidity positively on the next PT-antigen exposure with either vaccination or infection.
百日咳毒素（PT）是 的一种独特的毒力因子，因此也是无细胞百日咳疫苗的关键成分。虽然感染后的免疫力似乎比接种疫苗后持续时间更长，但确切机制尚不完全清楚。在这项研究中，我们比较了无细胞加强疫苗接种和感染后抗-PT IgG 抗体的总体结合强度（亲和力），以此作为评估长期保护的参数。本研究共纳入了来自丹麦和芬兰的 134 例血清学确诊患者和 112 例接受无细胞加强疫苗接种的儿童血清样本。首先通过 ELISA 测定抗-PT IgG 的浓度，然后通过两个单独的 ELISA 评估抗体亲和力：一种是使用尿素作为抗体和抗原结合的键断裂剂，并在样品之间保持恒定的抗-PT IgG 浓度，另一种是使用恒定的血清稀释比和去污剂。除了尿素之外，我们还首次比较了二乙胺和硫氰酸铵作为破坏剂之间的差异。如果使用恒定的血清稀释方法，亲和力与抗-PT IgG 抗体的浓度之间存在很强的斯皮尔曼相关性（>0.801），并且在丹麦，与疫苗接种者相比，患者的亲和力更高，但在芬兰并非如此。然而，如果使用恒定的抗-PT IgG 浓度，则未发现抗体浓度与亲和力之间存在相关性（= -0.157）。使用这种方法，与感染后相比，丹麦和芬兰的疫苗接种者在接种疫苗后抗体亲和力显著更高（<0.01）。发现最近一次加强疫苗接种后的时间较短会对下一次 PT 抗原暴露时的亲和力产生积极影响，无论是通过接种疫苗还是感染。
