Albritton Hannah L, Kozlowski Pamela A, Lillis Rebecca A, McGowin Chris L, Siren Julia D, Taylor Stephanie N, Ibana Joyce A, Buckner Lyndsey R, Shen Li, Quayle Alison J
Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, United States of America.
Department of Medicine, Division of Infectious Diseases, Louisiana State University Health Sciences Center, New Orleans, LA, United States of America.
PLoS One. 2017 Aug 10;12(8):e0183101. doi: 10.1371/journal.pone.0183101. eCollection 2017.
Chlamydia trachomatis (CT) is the leading sexually transmitted bacterial infection. The continued global burden of CT infection strongly predicates the need for a vaccine to supplement current chlamydial control programs. The correlates of protection against CT are currently unknown, but they must be carefully defined to guide vaccine design. The localized nature of chlamydial infection in columnar epithelial cells of the genital tract necessitates investigation of immunity at the site of infection. The purpose of this study was to develop a sensitive whole bacterial enzyme-linked immunosorbent assay (ELISA) to quantify and compare CT-specific IgG and IgA in sera and genital secretions from CT-infected women. To achieve this, elementary bodies (EBs) from two of the most common genital serovars (D and E) were attached to poly-L-lysine-coated microtiter plates with glutaraldehyde. EB attachment and integrity were verified by the presence of outer membrane antigens and the absence of bacterial cytoplasmic antigens. EB-specific IgG and IgA standards were developed by pooling sera with high titers of CT-specific antibodies from infected women. Serum, endocervical and vaginal secretions, and endocervical cytobrush specimens from CT-infected women were used to quantify CT-specific IgG and IgA which were then normalized to total IgG and IgA, respectively. Analyses of paired serum and genital samples revealed significantly higher proportions of EB-specific antibodies in genital secretions compared to sera. Cervical and vaginal secretions and cytobrush specimens had similar proportions of EB-specific antibodies, suggesting any one of these genital sampling techniques could be used to quantify CT-specific antibodies when appropriate normalization methodologies are implemented. Overall, these results illustrate the need to investigate genital tract CT antibody responses, and our assay provides a useful quantitative tool to assess natural immunity in defined clinical groups and CT vaccine trials.
沙眼衣原体（CT）是主要的性传播细菌感染源。CT感染在全球持续造成负担，这有力地表明需要一种疫苗来补充当前的衣原体控制计划。目前尚不清楚针对CT的保护性相关因素，但必须仔细界定这些因素以指导疫苗设计。衣原体感染局限于生殖道柱状上皮细胞，因此有必要研究感染部位的免疫情况。本研究的目的是开发一种灵敏的全细菌酶联免疫吸附测定（ELISA），以定量和比较CT感染女性血清和生殖道分泌物中CT特异性IgG和IgA。为实现这一目标，将两种最常见的生殖道血清型（D和E）的原体（EB）用戊二醛附着于聚-L-赖氨酸包被的微量滴定板上。通过外膜抗原的存在和细菌细胞质抗原的缺失来验证EB的附着和完整性。通过汇集来自感染女性的高滴度CT特异性抗体的血清来制备EB特异性IgG和IgA标准品。使用CT感染女性的血清、宫颈和阴道分泌物以及宫颈细胞刷标本定量CT特异性IgG和IgA，然后分别将其标准化为总IgG和IgA。配对血清和生殖道样本的分析显示，与血清相比，生殖道分泌物中EB特异性抗体的比例显著更高。宫颈和阴道分泌物以及细胞刷标本中EB特异性抗体的比例相似，这表明当实施适当的标准化方法时，这些生殖道采样技术中的任何一种都可用于定量CT特异性抗体。总体而言，这些结果表明需要研究生殖道CT抗体反应，并且我们的测定提供了一种有用的定量工具，可用于评估特定临床组中的自然免疫以及CT疫苗试验。
