Troelnikov Alexander, Armour Bridie, Putty Trishni, Aggarwal Anupriya, Akerman Anouschka, Milogiannakis Vanessa, Chataway Tim, King Jovanka, Turville Stuart G, Gordon Tom P, Wang Jing Jing
College of Medicine and Public Health, Flinders University, Bedford Park, Australia; SA Pathology, Adelaide, Australia.
College of Medicine and Public Health, Flinders University, Bedford Park, Australia; SA Pathology, Adelaide, Australia.
J Allergy Clin Immunol. 2023 Jul;152(1):290-301.e7. doi: 10.1016/j.jaci.2023.02.033. Epub 2023 Mar 23.
Predominantly antibody deficiency (PAD) is the most common category of inborn errors of immunity and is underpinned by impaired generation of appropriate antibody diversity and quantity. In the clinic, responses are interrogated by assessment of vaccination responses, which is central to many PAD diagnoses. However, the composition of the generated antibody repertoire is concealed from traditional quantitative measures of serological responses. Leveraging modern mass spectrometry-based proteomics (MS-proteomics), it is possible to elaborate the molecular features of specific antibody repertoires, which may address current limitations of diagnostic vaccinology.
We sought to evaluate serum antibody responses in patients with PAD following vaccination with a neo-antigen (severe acute respiratory syndrome coronavirus-2 vaccination) using MS-proteomics.
Following severe acute respiratory syndrome coronavirus-2 vaccination, serological responses in individuals with PAD and healthy controls (HCs) were assessed by anti-S1 subunit ELISA and neutralization assays. Purified anti-S1 subunit IgG and IgM was profiled by MS-proteomics for IGHV subfamily usage and somatic hypermutation analysis.
Twelve patients with PAD who were vaccine-responsive were recruited with 11 matched vaccinated HCs. Neutralization and end point anti-S1 titers were lower in PAD. All subjects with PAD demonstrated restricted anti-S1 IgG antibody repertoires, with usage of <5 IGHV subfamilies (median: 3; range 2-4), compared to ≥5 for the 11 HC subjects (P < .001). IGHV3-7 utilization was far less common in patients with PAD than in HCs (2 of 12 vs 10 of 11; P = .001). Amino acid substitutions due to somatic hypermutation per subfamily did not differ between groups. Anti-S1 IgM was present in 64% and 50% of HC and PAD cohorts, respectively, and did not differ significantly between HCs and patients with PAD.
This study demonstrates the breadth of anti-S1 antibodies elicited by vaccination at the proteome level and identifies stereotypical restriction of IGHV utilization in the IgG repertoire in patients with PAD compared with HC subjects. Despite uniformly pauci-clonal antibody repertoires some patients with PAD generated potent serological responses, highlighting a possible limitation of traditional serological techniques. These findings suggest that IgG repertoire restriction is a key feature of antibody repertoires in PAD.
主要抗体缺陷（PAD）是最常见的先天性免疫缺陷类型，其基础是适当抗体多样性和数量的产生受损。在临床上，通过评估疫苗接种反应来询问免疫反应，这是许多PAD诊断的核心。然而，传统的血清学反应定量测量方法无法揭示所产生抗体库的组成。利用基于现代质谱的蛋白质组学（MS-蛋白质组学），可以详细阐述特定抗体库的分子特征，这可能解决当前诊断疫苗学的局限性。
我们试图使用MS-蛋白质组学评估PAD患者接种新抗原（严重急性呼吸综合征冠状病毒2疫苗）后的血清抗体反应。
在接种严重急性呼吸综合征冠状病毒2疫苗后，通过抗S1亚基ELISA和中和试验评估PAD患者和健康对照（HC）的血清学反应。通过MS-蛋白质组学对纯化的抗S1亚基IgG和IgM进行分析，以确定IGHV亚家族的使用情况和体细胞超突变分析。
招募了12名对疫苗有反应的PAD患者和11名匹配的接种疫苗的HC。PAD患者的中和抗体和终点抗S1滴度较低。所有PAD患者均表现出抗S1 IgG抗体库受限，使用的IGHV亚家族<5个（中位数：3；范围2-4），而11名HC受试者≥5个（P <.001）。与HC相比，PAD患者中IGHV3-7 的利用率远低于HC（12例中有2例，11例中有10例；P =.001）。各亚家族因体细胞超突变导致的氨基酸替换在两组之间没有差异。抗S1 IgM分别存在于64%的HC队列和50%的PAD队列中，HC和PAD患者之间没有显著差异。
本研究在蛋白质组水平上展示了疫苗接种引发的抗S1抗体的广度，并确定了与HC受试者相比，PAD患者IgG库中IGHV使用的典型限制。尽管抗体库均为寡克隆，但一些PAD患者产生了有效的血清学反应，突出了传统血清学技术可能存在的局限性。这些发现表明IgG库限制是PAD抗体库的一个关键特征。
