B Cell Immunology, German Cancer Research Center, Heidelberg, Germany.
Biosciences Faculty, University of Heidelberg, Germany.
EMBO Mol Med. 2023 Jun 7;15(6):e17454. doi: 10.15252/emmm.202317454. Epub 2023 Apr 21.
Human monoclonal antibodies (mAbs) against the central repeat and junction domain of Plasmodium falciparum circumsporozoite protein (PfCSP) have been studied extensively to guide malaria vaccine design compared to antibodies against the PfCSP C terminus. Here, we describe the molecular characteristics and protective potential of 73 germline and mutated human mAbs against the highly immunogenic PfCSP C-terminal domain. Two mAbs recognized linear epitopes in the C-terminal linker with sequence similarity to repeat and junction motifs, whereas all others targeted conformational epitopes in the α-thrombospondin repeat (α-TSR) domain. Specificity for the polymorphic Th2R/Th3R but not the conserved RII+/CS.T3 region in the α-TSR was associated with IGHV3-21/IGVL3-21 or IGLV3-1 gene usage. Although the C terminus specific mAbs showed signs of more efficient affinity maturation and class-switching compared to anti-repeat mAbs, live sporozoite binding and inhibitory activity was limited to a single C-linker reactive mAb with cross-reactivity to the central repeat and junction. The data provide novel insights in the human anti-C-linker and anti-α-TSR antibody response that support exclusion of the PfCSP C terminus from malaria vaccine designs.
人类针对恶性疟原虫环子孢子蛋白(PfCSP)中央重复区和连接区的单克隆抗体(mAbs)在疟疾疫苗设计方面的研究已经广泛开展,与针对 PfCSP C 末端的抗体相比,这些抗体具有重要的指导意义。在这里,我们描述了 73 种针对 PfCSP C 末端结构域高度免疫原性的人源性单克隆抗体的分子特征和保护潜力。两种 mAbs 识别 C 末端连接子中的线性表位,这些表位与重复区和连接区的序列相似,而其他所有 mAb 则针对 α-血栓素样重复(α-TSR)结构域中的构象表位。针对多态性 Th2R/Th3R,而非 α-TSR 中的保守 RII+/CS.T3 区的特异性与 IGHV3-21/IGVL3-21 或 IGLV3-1 基因的使用有关。尽管针对 C 末端的 mAb 与针对重复区的 mAb 相比表现出更有效的亲和力成熟和类别转换迹象,但活孢子结合和抑制活性仅限于与中央重复区和连接区具有交叉反应性的单个 C 连接子反应性 mAb。该数据为人类针对 C 连接子和 α-TSR 抗体的反应提供了新的见解,支持从疟疾疫苗设计中排除 PfCSP C 末端。
Sci Immunol. 2022-6-10