Laboratory of Human Pathologies Biology and Center of Genomic of Human Pathologies Biology, Faculty of Sciences, Mohammed V University, Rabat, Morocco.
Mohammed VI Center for Research and Innovation, Rabat, Morocco.
Hum Antibodies. 2024;32(3):85-106. doi: 10.3233/HAB-230017.
Following infection and vaccination against SARS-CoV-2, humoral components of the adaptive immune system play a key role in protecting the host. Specifically, B cells generate high-affinity antibodies against various antigens of the virus. In this review, we discuss the mechanisms of immunity initiation through both natural infection and vaccination, shedding light on the activation of B cell subsets in response to SARS-CoV-2 infection and vaccination. The innate immune system serves as the initial line of primary and nonspecific defence against viruses. However, within several days following infection or a vaccine dose, a virus-specific immune response is initiated, primarily by B cells that produce antibodies. These antibodies contribute to the resolution of the disease. Subsequently, these B cells transition into memory B cells, which play a crucial role in providing long-term immunity against the virus. CD4+ T helper cells initiate a cascade, leading to B cell somatic hypermutation, germinal center memory B cells, and the production of neutralizing antibodies. B-cell dysfunction can worsen disease severity and reduce vaccine efficacy. Notably, individuals with B cell immunodeficiency show lower IL-6 production. Furthermore, this review delves into several aspects of immune responses, such as hybrid immunity, which has shown promise in boosting broad-spectrum protection. Cross-reactive immunity is under scrutiny as well, as pre-existing antibodies can offer protection against the disease. We also decipher breakthrough infection mechanisms, especially with the novel variants of the virus. Finally, we discuss some potential therapeutic solutions regarding B cells including convalescent plasma therapy, B-1 cells, B regulatory cell (Breg) modulation, and the use of neutralizing monoclonal antibodies in combating the infection. Ongoing research is crucial to grasp population immunity trends and assess the potential need for booster doses in maintaining effective immune responses against potential viral threats.
在感染和接种 SARS-CoV-2 疫苗后，适应性免疫系统的体液成分在保护宿主方面发挥着关键作用。具体来说，B 细胞会针对病毒的各种抗原产生高亲和力的抗体。在这篇综述中，我们讨论了通过自然感染和接种疫苗来启动免疫的机制，阐明了 B 细胞亚群对 SARS-CoV-2 感染和接种疫苗的反应激活机制。先天免疫系统是宿主抵御病毒的第一道也是非特异性防线。然而，在感染或接种一剂疫苗后的数天内，就会启动针对病毒的特异性免疫反应，主要由产生抗体的 B 细胞来启动。这些抗体有助于疾病的康复。随后，这些 B 细胞转变为记忆 B 细胞，在提供针对病毒的长期免疫方面发挥着至关重要的作用。CD4+T 辅助细胞启动级联反应，导致 B 细胞体细胞超突变、生发中心记忆 B 细胞和中和抗体的产生。B 细胞功能障碍会加重疾病严重程度并降低疫苗效力。值得注意的是，B 细胞免疫缺陷个体的白细胞介素 6 产生水平较低。此外，本文还深入探讨了免疫反应的多个方面，如混合免疫，混合免疫在增强广谱保护方面显示出了潜力。交叉反应性免疫也受到了关注，因为预先存在的抗体可以提供针对疾病的保护。我们还解析了突破性感染的机制，特别是新型病毒变体。最后，我们讨论了一些针对 B 细胞的潜在治疗解决方案，包括恢复期血浆疗法、B1 细胞、B 调节细胞（Breg）调节以及中和单克隆抗体在抗击感染方面的应用。持续的研究对于了解人群免疫趋势以及评估维持针对潜在病毒威胁的有效免疫反应的潜在需要至关重要。
