Jang A-Yeung, Choi Min-Joo, Zhi Yong, Ji Hyun-Jung, Noh Ji-Yun, Yoon Jin-Gu, Cheong Hee-Jin, Kim Woo-Joo, Seo Ho-Seong, Song Joon-Young
Department of Internal Medicine, Division of Infectious Diseases, Korea University College of Medicine, Seoul 08308, Korea.
Department of Internal Medicine, International St. Mary's Hospital, Catholic Kwandong University College of Medicine, Incheon 22711, Korea.
Vaccines (Basel). 2021 May 21;9(6):545. doi: 10.3390/vaccines9060545.
(group B , GBS) is a leading cause of neonatal sepsis and meningitis in infants. Limitations of prenatal GBS screening and intrapartum antibiotic prophylaxis render developing GBS vaccines a high priority. In this study, we developed an enzyme-linked immunosorbent assay (ELISA) for the practical and large-scale evaluation of GBS capsular polysaccharide (PS) vaccine immunogenicity against three main serotypes, Ia, III, and V. GBS-ELISA was developed and subsequently validated using a standardized curve-fitting four-parameter logistic method. Specificity was measured using adsorption of serum with homologous and heterologous PS. Homologous adsorption showed a ≥75% inhibition of all three serotypes, whereas with heterologous PS, IgG GBS-ELISA inhibited only ≤25% of serotypes III and V. However, with serotype Ia, IgG antibody levels decreased by >50%, even after adsorption with heterologous PS (III or V). In comparison, the inhibition opsonophagocytic killing assay (OPA) of serotypes Ia GBS exhibited a reduction in opsonophagocytic activity of only 20% and 1.1% for serotypes III and V GBS, respectively. The precision of the GBS-ELISA was assessed in five independent experiments using four serum samples. The coefficient of variation was <5% for all three serotypes. This standardized GBS-ELISA would be useful for GBS vaccine development and its evaluation.
B组链球菌（GBS）是婴儿新生儿败血症和脑膜炎的主要病因。产前GBS筛查和产时抗生素预防的局限性使得开发GBS疫苗成为当务之急。在本研究中，我们开发了一种酶联免疫吸附测定（ELISA），用于对针对三种主要血清型Ia、III和V的GBS荚膜多糖（PS）疫苗免疫原性进行实际大规模评估。开发了GBS-ELISA，并随后使用标准化曲线拟合四参数逻辑方法进行了验证。使用同源和异源PS吸附血清来测量特异性。同源吸附对所有三种血清型均显示出≥75%的抑制作用，而异源PS吸附时，IgG GBS-ELISA仅对血清型III和V抑制≤25%。然而，对于血清型Ia，即使在用异源PS（III或V）吸附后，IgG抗体水平仍下降>50%。相比之下，血清型Ia GBS的抑制性吞噬细胞杀伤试验（OPA）中，血清型III和V GBS的吞噬细胞活性分别仅降低20%和1.1%。使用四个血清样本在五个独立实验中评估了GBS-ELISA的精密度。所有三种血清型的变异系数均<5%。这种标准化的GBS-ELISA将有助于GBS疫苗的开发及其评估。
