Caboré Raïssa Nadège, Maertens Kirsten, Dobly Alexandre, Leuridan Elke, Van Damme Pierre, Huygen Kris
a National Reference Centre for Bordetella & National Reference Centre for Toxigenic Corynebacteria , Scientific Service Immunology, Scientific Institute of Public Health (WIV-ISP) , Brussels , Belgium.
b Centre for the Evaluation of Vaccination , Vaccine & Infectious Diseases Institute, University of Antwerp , Antwerp , Belgium.
Virulence. 2017 Oct 3;8(7):1245-1254. doi: 10.1080/21505594.2017.1296998. Epub 2017 Feb 22.
Maternal antibodies induced by vaccination during pregnancy cross the placental barrier and can close the susceptibility gap to pertussis in young infants up to the start of primary immunization. As not only the quantity but also the quality of circulating antibodies is important for protection, we assessed whether maternal immunization affects the avidity of infant vaccine-induced IgG antibodies, in the frame of a prospective clinical trial on pregnancy vaccination in Belgium. Infants born from Tdap (Boostrix®) vaccinated (N = 55) and unvaccinated (N = 26) mothers were immunized with a hexavalent pertussis containing vaccine (Infanrix Hexa®) at 8, 12 and 16 weeks, followed by a fourth dose at 15 months of age. Right before and one month after this fourth vaccine dose, the avidity of IgG antibodies against diphtheria toxin (DT), tetanus toxin (TT), pertussis toxin (PT), filamentous hemagglutinin (FHA) and pertactin (Prn) was determined using 1.5 M ammonium thiocyanate as dissociating agent. In both groups, antibody avidity was moderate for TT, PT, FHA and Prn and low for DT after priming. After a fourth dose, antibody avidity increased significantly to high avidity for TT and PT, whereas it remained moderate for FHA and Prn and low for DT. The avidity correlated positively with antibody level in both study groups, yet not significantly for PT. When comparing both study groups, only PT-specific antibodies showed significantly lower avidity in infants born from vaccinated than from unvaccinated mothers after the fourth vaccine dose. The clinical significance of lower avidity of vaccine induced infant antibodies after maternal vaccination, if any, needs further investigation.
孕期接种疫苗所诱导产生的母体抗体可穿过胎盘屏障，在婴儿进行初次免疫接种之前，能够缩小其对百日咳的易感性差距。由于循环抗体的数量和质量对于保护作用均很重要，因此，在比利时一项关于孕期疫苗接种的前瞻性临床试验框架内，我们评估了母体免疫接种是否会影响婴儿疫苗诱导产生的IgG抗体的亲和力。对分别来自接种了无细胞百白破疫苗（Tdap，商品名：博思rix）（N = 55）和未接种疫苗（N = 26）母亲的婴儿，在其8周、12周和16周龄时用含六价百日咳疫苗（商品名：英凡里尔六联疫苗）进行免疫接种，随后在15月龄时接种第四剂疫苗。在第四剂疫苗接种前及接种后1个月，使用1.5M硫氰酸铵作为解离剂，测定针对白喉毒素（DT）、破伤风毒素（TT）、百日咳毒素（PT）、丝状血凝素（FHA）和百日咳黏附素（Prn）的IgG抗体的亲和力。在两组中，初次免疫后针对TT、PT、FHA和Prn的抗体亲和力为中等，而针对DT的抗体亲和力较低。接种第四剂疫苗后，针对TT和PT的抗体亲和力显著升高至高亲和力，而针对FHA和Prn的抗体亲和力仍为中等，针对DT的抗体亲和力则较低。在两个研究组中，抗体亲和力均与抗体水平呈正相关，但针对PT的相关性不显著。比较两个研究组时，仅第四剂疫苗接种后，接种疫苗母亲所生婴儿体内针对PT的特异性抗体的亲和力显著低于未接种疫苗母亲所生婴儿。母体接种疫苗后婴儿疫苗诱导抗体的较低亲和力的临床意义（如有）需要进一步研究。
