There are notable inter-individual variations in vaccine-specific antibody responses in vaccinated children. The aim of our study was to investigate whether early-life environmental factors and adaptive immune maturation prior and close to measles-mumps-rubella (MMR) immunization relate to magnitudes of vaccine-specific antibody titers. In the FARMFLORA birth cohort, including both farming and non-farming families, children were immunized with the MMR vaccine at 18 months of age. MMR vaccine-induced antibody titers were measured in plasma samples obtained at 36 months of age. Infants' blood samples obtained at birth, 3-5 days and at 4 and 18 months of age were analyzed for T- and B-cell numbers, proportions of naive and memory T and B cells, and fractions of putative regulatory T cells. Multivariate factor analyses show that higher anti-MMR antibody titers were associated with a lower degree of adaptive immune maturation, that is, lower proportions of memory T cells and a lower capacity of mononuclear cells to produce cytokines, but with higher proportions of putative regulatory T cells. Further, children born by cesarean section (CS) had significantly higher anti-measles titers than vaginally-born children; and CS was found to be associated with delayed adaptive immunity. Also, girls presented with significantly higher anti-mumps and anti-rubella antibody levels than boys at 36 months of age. These results indicate that delayed adaptive immune maturation before and in close proximity to immunization seems to be advantageous for the ability of children to respond with higher anti-MMR antibody levels after vaccination.

中文翻译：

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延迟的适应性免疫与儿童MMR疫苗诱导的更高抗体滴度有关。

在接种疫苗的儿童中，疫苗特异性抗体反应之间存在显着个体差异。我们研究的目的是调查麻疹-腮腺炎-风疹（MMR）免疫之前和接近免疫早期的环境因素和适应性免疫成熟是否与疫苗特异性抗体滴度的大小有关。在FARMFLORA出生队列中，包括农业和非农业家庭，均在18个月大时使用MMR疫苗对儿童进行了免疫。在36个月大的血浆样品中测量了MMR疫苗诱导的抗体滴度。分析婴儿出生时，3-5天以及4和18个月大时的血液样本中的T细胞和B细胞数量，幼稚和记忆T细胞和B细胞的比例以及假定的调节性T细胞的分数。多因素分析表明，较高的抗MMR抗体滴度与较低的适应性免疫成熟度有关，即较低的记忆T细胞比例和较低的单核细胞产生细胞因子的能力，但较高的推定调节性T细胞比例细胞。此外，剖宫产（CS）出生的孩子比阴道出生的孩子具有更高的抗麻疹滴度。并且发现CS与延迟的适应性免疫有关。此外，女孩在36个月大时表现出的抗腮腺炎和抗风疹抗体水平明显高于男孩。这些结果表明，在免疫接种之前和紧邻免疫接种之前，延迟的适应性免疫成熟似乎有利于儿童在接种疫苗后以更高的抗MMR抗体水平做出反应的能力。