De Oliveira Athos Silva, Versteeg Leroy, Briggs Neima, Adhikari Rakesh, Villar Maria Jose, Redd JeAnna R, Hotez Peter, Bottazzi Maria Elena, Pollet Jeroen
Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine, Houston, Texas, United States of America.
Texas Children's Hospital Center for Vaccine Development, Houston, Texas, United States of America.
PLoS Negl Trop Dis. 2025 Jan 10;19(1):e0012809. doi: 10.1371/journal.pntd.0012809. eCollection 2025 Jan.
The antigen Na-GST-1, expressed by the hookworm Necator americanus, plays crucial biochemical roles in parasite survival. This study explores the development of mRNA vaccine candidates based on Na-GST-1, building on the success of recombinant Na-GST-1 (rNa-GST-1) protein, currently assessed as a subunit vaccine candidate, which has shown promise in preclinical and clinical studies.
METHODOLOGY/FINDINGS: By leveraging the flexible design of RNA vaccines and protein intracellular trafficking signal sequences, we developed three variants of Na-GST-1 as native (cytosolic), secretory, and plasma membrane-anchored (PM) antigens. After one immunization in mice, mRNA vaccines induced an earlier onset of antigen-specific antibodies compared to rNa-GST-1. Following two immunizations, mRNA vaccines induced similar or superior levels of antigen-specific antibodies compared to rNa-GST-1. Secretory Na-GST-1 was comparable to rNa-GST1 in producing neutralizing antibodies against Na-GST-1's thiol transferase activity, while native Na-GST-1 induced a more robust CD8+ T cell response due to its intracellular accumulation. Although PM Na-GST-1 elicited one of highest titers of antigen-specific antibody and a diverse set of memory T-cell populations, it resulted in a lower ratio of neutralizing antibodies after IgG purification compared to the other vaccine candidates.
CONCLUSIONS/SIGNIFICANCE: These findings emphasize the importance of antigen localization in tailoring immune responses and suggest that extracellular antigens are more effective for inducing humoral responses, whereas cytosolic antigen accumulation enhances MHC-1 peptide presentation. Future studies will determine if these in vitro and immunogenicity findings translate to in vivo efficacy. Altogether, mRNA vaccines offer numerous possibilities in the development of multivalent vaccines with single or multiple antigens.
美洲钩虫表达的抗原Na-GST-1在寄生虫生存中发挥着关键的生化作用。本研究基于重组Na-GST-1（rNa-GST-1）蛋白的成功，探索基于Na-GST-1的mRNA候选疫苗的开发。rNa-GST-1蛋白目前被评估为一种亚单位疫苗候选物，已在临床前和临床研究中显示出前景。
方法/发现：通过利用RNA疫苗的灵活设计和蛋白质细胞内运输信号序列，我们开发了三种Na-GST-1变体，分别作为天然（胞质）、分泌型和质膜锚定（PM）抗原。在小鼠中进行一次免疫后，与rNa-GST-1相比，mRNA疫苗诱导抗原特异性抗体的出现更早。两次免疫后，与rNa-GST-1相比，mRNA疫苗诱导的抗原特异性抗体水平相似或更高。分泌型Na-GST-1在产生针对Na-GST-1硫醇转移酶活性的中和抗体方面与rNa-GST1相当，而天然Na-GST-1由于其在细胞内的积累诱导了更强的CD8 + T细胞反应。尽管PM Na-GST-1引发了最高滴度的抗原特异性抗体之一和多种记忆T细胞群体，但与其他候选疫苗相比，IgG纯化后其产生的中和抗体比例较低。
结论/意义：这些发现强调了抗原定位在调节免疫反应中的重要性，并表明细胞外抗原在诱导体液反应方面更有效，而胞质抗原积累增强了MHC-1肽的呈递。未来的研究将确定这些体外和免疫原性发现是否转化为体内疗效。总之，mRNA疫苗在开发单抗原或多抗原的多价疫苗方面提供了众多可能性。
