MacDonald Nicholas J, Nguyen Vu, Shimp Richard, Reiter Karine, Herrera Raul, Burkhardt Martin, Muratova Olga, Kumar Krishan, Aebig Joan, Rausch Kelly, Lambert Lynn, Dawson Nikiah, Sattabongkot Jetsumon, Ambroggio Xavier, Duffy Patrick E, Wu Yimin, Narum David L
From the Laboratory of Malaria Immunology and Vaccinology, NIAID, National Institutes of Health, Rockville, Maryland 20852.
the Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400 Thailand, and.
J Biol Chem. 2016 Sep 16;291(38):19913-22. doi: 10.1074/jbc.M116.732305. Epub 2016 Jul 18.
Development of a Plasmodium falciparum (Pf) transmission blocking vaccine (TBV) has the potential to significantly impact malaria control. Antibodies elicited against sexual stage proteins in the human bloodstream are taken up with the blood meal of the mosquitoes and inactivate parasite development in the mosquito. In a phase 1 trial, a leading TBV identified as Pfs25-EPA/Alhydrogel® appeared safe and immunogenic, however, the level of Pfs25-specific antibodies were likely too low for an effective vaccine. Pfs230, a 230-kDa sexual stage protein expressed in gametocytes is an alternative vaccine candidate. A unique 6-cysteine-rich domain structure within Pfs230 have thwarted its recombinant expression and characterization for clinical evaluation for nearly a quarter of a century. Here, we report on the identification, biochemical, biophysical, and immunological characterization of recombinant Pfs230 domains. Rabbit antibodies generated against recombinant Pfs230 domains blocked mosquito transmission of a laboratory strain and two field isolates using an ex vivo assay. A planned clinical trial of the Pfs230 vaccine is a significant step toward the potential development of a transmission blocking vaccine to eliminate malaria.
恶性疟原虫传播阻断疫苗(TBV)的研发有可能对疟疾控制产生重大影响。人体血液中针对有性阶段蛋白产生的抗体,会随着蚊子吸食血液而被摄入,并使蚊子体内的寄生虫发育失活。在一项1期试验中,一种被鉴定为Pfs25-EPA/Alhydrogel®的领先TBV似乎安全且具有免疫原性,然而,Pfs25特异性抗体的水平可能过低,无法形成有效的疫苗。Pfs230是一种在配子体中表达的230 kDa有性阶段蛋白,是另一种疫苗候选物。近25年来,Pfs230中独特的富含6个半胱氨酸的结构域阻碍了其重组表达及用于临床评估的特性研究。在此,我们报告重组Pfs230结构域的鉴定、生化、生物物理和免疫学特性。使用体外试验,针对重组Pfs230结构域产生的兔抗体阻断了实验室菌株和两种野外分离株的蚊子传播。Pfs230疫苗的计划临床试验是朝着开发潜在的传播阻断疫苗以消除疟疾迈出的重要一步。