Giardina Peter C, Longworth Emma, Evans-Johnson Renee E, Bessette Michaelene L, Zhang Hong, Borrow Ray, Madore Dace, Fernsten Philip
Department of Applied Immunology and Microbiology, Wyeth Vaccines Research, 401 Middletown Road, Pearl River, NY 10965, USA.
Clin Diagn Lab Immunol. 2005 May;12(5):586-92. doi: 10.1128/CDLI.12.5.586-592.2005.
The capsular polysaccharide of Neisseria meningitidis serogroup W135 is expressed in both O-acetyl-positive (OA+) and O-acetyl-negative (OA-) forms. This study investigates the impact of OA status (OA+ versus OA-) on serological measurements of anti-W135 immunoglobulin G (IgG) antibodies in immunized adults. W135-specific serum antibody assignments were made for 28 postimmunization sera from adults by enzyme-linked immunosorbent assay using the meningococcal standard reference serum CDC1992. The established IgG concentration in micrograms per milliliter ([IgG]microg/ml) for CDC1992 against OA+ antigen (16.2 microg/ml) was used as a reference to assign a concentration of 10.13 microg/ml IgG against OA- antigen by cross-standardization. Overall, the IgG assignments for these sera were higher against OA+ antigen (geometric mean concentration [GMC] = 7.16 microg/ml) than against OA- antigen (GMC = 2.84 microg/ml). However, seven sera showed higher specific [IgG]microg/ml values against the OA+ antigen than against the OA- antigen. These sera were also distinguished by the inability of fluid-phase OA- antigen to compete for antibody binding to OA+ solid-phase antigen. Although there was no overall difference in functional activity measured by complement-mediated serum bactericidal assay (SBA) against OA+ and OA- target bacteria (geometric mean titers of 9,642 and 9,045, respectively), three serum specimens showed a large difference in SBA antibody titers against OA+ versus OA- W135 target bacteria, which may reflect different epitope specificities for these sera. Our data indicate that, for some sera, the agreement in anti-OA+ versus anti-OA- W135 IgG assignments is serum specific and does not reflect the functional (killing) activity in vitro.
脑膜炎奈瑟菌W135群的荚膜多糖以O - 乙酰化阳性（OA +）和O - 乙酰化阴性（OA -）两种形式表达。本研究调查了OA状态（OA +与OA -）对免疫成人中抗W135免疫球蛋白G（IgG）抗体血清学检测的影响。使用脑膜炎球菌标准参考血清CDC1992，通过酶联免疫吸附测定法对28份成人免疫后血清进行了W135特异性血清抗体测定。以CDC1992针对OA +抗原的既定IgG浓度（每毫升微克数[IgG]μg/ml，为16.2μg/ml）作为参考，通过交叉标准化确定针对OA -抗原的IgG浓度为10.13μg/ml。总体而言，这些血清针对OA +抗原的IgG测定值（几何平均浓度[GMC] = 7.16μg/ml）高于针对OA -抗原的测定值（GMC = 2.84μg/ml）。然而，有7份血清针对OA +抗原的特异性[IgG]μg/ml值高于针对OA -抗原的值。这些血清的另一个特点是液相OA -抗原无法竞争抗体与OA +固相抗原的结合。尽管通过补体介导的血清杀菌试验（SBA）测定的针对OA +和OA -靶细菌的功能活性没有总体差异（几何平均滴度分别为9,642和9,045），但有3份血清标本针对OA +与OA - W135靶细菌显示出SBA抗体滴度的巨大差异，这可能反映了这些血清不同的表位特异性。我们的数据表明，对于某些血清，抗OA +与抗OA - W135 IgG测定结果的一致性具有血清特异性，并不反映体外的功能（杀菌）活性。
