Rodrigues Kristen A, Cottrell Christopher A, Steichen Jon M, Groschel Bettina, Abraham Wuhbet, Suh Heikyung, Agarwal Yash, Ni Kaiyuan, Chang Jason Y H, Yousefpour Parisa, Melo Mariane B, Schief William R, Irvine Darrell J
Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
Harvard-MIT Health Sciences and Technology Program, Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
NPJ Vaccines. 2023 Aug 12;8(1):117. doi: 10.1038/s41541-023-00711-0.
In the ongoing effort to develop a vaccine against HIV, vaccine approaches that promote strong germinal center (GC) responses may be critical to enable the selection and affinity maturation of rare B cell clones capable of evolving to produce broadly neutralizing antibodies. We previously demonstrated an approach for enhancing GC responses and overall humoral immunity elicited by alum-adjuvanted protein immunization via the use of phosphoserine (pSer) peptide-tagged immunogens that stably anchor to alum particles via ligand exchange with the alum particle surface. Here, using a clinically relevant stabilized HIV Env trimer termed MD39, we systematically evaluated the impact of several parameters relevant to pSer tag composition and trimer immunogen design to optimize this approach, including phosphate valency, amino acid sequence of the trimer C-terminus used for pSer tag conjugation, and structure of the pSer tag. We also tested the impact of co-administering a potent saponin/monophosphoryl lipid A (MPLA) nanoparticle co-adjuvant with alum-bound trimers. We identified MD39 trimer sequences bearing an optimized positively-charged C-terminal amino acid sequence, which, when conjugated to a pSer tag with four phosphates and a polypeptide spacer, bound very tightly to alum particles while retaining a native Env-like antigenicity profile. This optimized pSer-trimer design elicited robust antigen-specific GC B cell and serum IgG responses in mice. Through this optimization, we present a favorable MD39-pSer immunogen construct for clinical translation.
在不断努力研发抗HIV疫苗的过程中，促进强大生发中心（GC）反应的疫苗策略对于筛选和亲和力成熟那些能够进化产生广泛中和抗体的稀有B细胞克隆可能至关重要。我们之前展示了一种通过使用磷酸丝氨酸（pSer）肽标记的免疫原增强铝佐剂蛋白免疫诱导的GC反应和整体体液免疫的方法，该免疫原通过与铝颗粒表面进行配体交换而稳定锚定在铝颗粒上。在此，我们使用一种临床相关的稳定化HIV Env三聚体MD39，系统评估了与pSer标签组成和三聚体免疫原设计相关的几个参数对优化该方法的影响，包括磷酸化合价、用于pSer标签偶联的三聚体C末端氨基酸序列以及pSer标签的结构。我们还测试了将一种有效的皂苷/单磷酰脂质A（MPLA）纳米颗粒共佐剂与铝结合的三聚体共同给药的影响。我们鉴定出带有优化的带正电荷C末端氨基酸序列的MD39三聚体序列，当与具有四个磷酸基团和一个多肽间隔区的pSer标签偶联时，能非常紧密地结合到铝颗粒上，同时保留类似天然Env的抗原性特征。这种优化的pSer - 三聚体设计在小鼠中引发了强烈的抗原特异性GC B细胞和血清IgG反应。通过这种优化，我们提出了一种用于临床转化的良好MD39 - pSer免疫原构建体。
