Potent Malaria Transmission-Blocking Antibody Responses Elicited by Plasmodium falciparum Pfs25 Expressed in Escherichia coli after Successful Protein Refolding
Potent Malaria Transmission-Blocking Antibody Responses Elicited by Plasmodium falciparum Pfs25 Expressed in Escherichia coli after Successful Protein Refolding
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DOI：
10.1128/iai.01438-13
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发表时间：
2014-04-01
影响因子：
3.1
通讯作者：
Kumar, Nirbhay
中科院分区：
文献类型：
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作者：
Kumar, Rajesh;Angov, Evelina;Kumar, Nirbhay
Pfs 25是一种恶性疟原虫传播阻断疫苗靶抗原，其功能性构象具有引发有效免疫原性的潜力，其生产仍然是一个重大挑战。在目前的研究中，密码子协调重组Pfs 25（CHrPfs 25）在大肠杆菌中表达，并在简单的氧化重折叠步骤后的纯化蛋白保留还原敏感的构象表位的传输阻断单克隆抗体。在小鼠的临床前研究中，在几种佐剂中配制的CHrPfs 25引起强免疫原性。免疫后产生的抗体识别恶性疟原虫活配子表面上的天然Pfs 25，并表现出完全的疟疾传播阻断活性。即使在完全弗氏佐剂和Montanide ISA 51组中免疫小鼠的血清以1：128稀释后，以及在明矾组中小鼠的血清以1：16稀释后，传播阻断效力仍为100%。阻断是由抗体介导的;纯化的IgG在低至31.25 μ g/ml的浓度下，在采用两种不同种类的蚊子（冈比亚按蚊和斯氏按蚊）的膜摄食测定中表现出100%的传输阻断。本研究首次证明了rPfs 25在大肠杆菌中的成功表达。杆菌纯化蛋白免疫诱导的抗体具有极强的疟疾传播阻断活性，为进一步评价E.大肠杆菌衍生的CHrPfs 25作为疟疾传播阻断疫苗在人类临床试验中的应用
Production of Pfs25, a Plasmodium falciparum transmission-blocking vaccine target antigen, in functional conformation with the potential to elicit effective immunogenicity still remains a major challenge. In the current study, codon-harmonized recombinant Pfs25 (CHrPfs25) was expressed in Escherichia coli, and purified protein after simple oxidative refolding steps retained reduction-sensitive conformational epitopes of transmission-blocking monoclonal antibodies. CHrPfs25 formulated in several adjuvants elicited strong immunogenicity in preclinical studies in mice. Antibodies elicited after immunization recognized native Pfs25 on the surface of live gametes of P. falciparum and demonstrated complete malaria transmission-blocking activity. The transmission-blocking efficacy was 100% even after a 1:128 dilution of sera from immunized mice in the complete Freund's adjuvant and Montanide ISA51 groups and after a 1:16 dilution of sera from mice in the alum group. The blocking was mediated by antibodies; purified IgG at concentrations as low as 31.25 mu g/ml exhibited 100% transmission blocking in membrane feeding assays employing two different species of mosquitoes, Anopheles gambiae and Anopheles stephensi. This study provides the first evidence for successful expression of biologically functional rPfs25 in E. coli. The extremely potent malaria transmission-blocking activity of antibodies elicited by immunization with purified protein provides strong support for further evaluation of E. coli-derived CHrPfs25 as a malaria transmission-blocking vaccine in human clinical trials.