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Abstract：
BACKGROUND: Malaria, a preventive and treatable disease, is still responsible for annual deaths reported in most tropical regions, principally in sub-Saharan Africa. Subunit recombinant transmission-blocking vaccines (TBVs) have been proposed as promising vaccines to succeed in malaria elimination and eradication. Here, a provisional study was designed to assess the immunogenicity and functional activity of alanyl aminopeptidase N (APN1) of Anopheles stephensi, as a TBV candidate, administered with MPL, CpG, and QS21 adjuvants in the murine model.
RESULTS: The mouse groups were immunized with recombinant APN1 (rAPN1) alone or formulated with CpG, MPL, QS-21, or a combination of adjuvants (CMQ), and the elicited immune responses were evaluated after the third immunization. The standard membrane feeding assay (SMFA) measured the functional activity of antibodies against bacterial-expressed APN1 protein in adjuvanted vaccine groups on transmission of P. falciparum (NF54) to An. stephensi mosquitoes. Evaluation of mice vaccinated with rAPN1 formulated with distinct adjuvants manifested a significant increase in the high-avidity level of anti-APN1 IgG and IgG subclasses; however, rAPN1 induced the highest level of high-avidity anti-APN1 IgG1, IgG2a, and IgG2b antibodies in the immunized vaccine group 5 (APN1/CMQ). In addition, vaccine group 5 (receiving APN1/CMQ), had still the highest level of anti-APN1 IgG antibodies relative to other immunized groups after six months, on day 180. The SMFA data indicates a trend towards higher transmission-reducing activity in groups 2 and 5, which received the antigen formulated with CpG or a combination of three adjuvants.
CONCLUSIONS: The results have shown the capability of admixture to stimulate high-affinity and long-lasting antibodies against the target antigen to hinder Plasmodium parasite development in the mid-gut of An. stephensi. The attained results authenticated APN1/CMQ and APN1/CpG as a potent APN1-based TBV formulation which will be helpful in designing a vaccine in the future.
RESULTS: The mouse groups were immunized with recombinant APN1 (rAPN1) alone or formulated with CpG, MPL, QS-21, or a combination of adjuvants (CMQ), and the elicited immune responses were evaluated after the third immunization. The standard membrane feeding assay (SMFA) measured the functional activity of antibodies against bacterial-expressed APN1 protein in adjuvanted vaccine groups on transmission of P. falciparum (NF54) to An. stephensi mosquitoes. Evaluation of mice vaccinated with rAPN1 formulated with distinct adjuvants manifested a significant increase in the high-avidity level of anti-APN1 IgG and IgG subclasses; however, rAPN1 induced the highest level of high-avidity anti-APN1 IgG1, IgG2a, and IgG2b antibodies in the immunized vaccine group 5 (APN1/CMQ). In addition, vaccine group 5 (receiving APN1/CMQ), had still the highest level of anti-APN1 IgG antibodies relative to other immunized groups after six months, on day 180. The SMFA data indicates a trend towards higher transmission-reducing activity in groups 2 and 5, which received the antigen formulated with CpG or a combination of three adjuvants.
CONCLUSIONS: The results have shown the capability of admixture to stimulate high-affinity and long-lasting antibodies against the target antigen to hinder Plasmodium parasite development in the mid-gut of An. stephensi. The attained results authenticated APN1/CMQ and APN1/CpG as a potent APN1-based TBV formulation which will be helpful in designing a vaccine in the future.
摘要：
背景：疟疾，一种可预防和治疗的疾病，仍然是大多数热带地区报告的年度死亡原因，主要在撒哈拉以南非洲。已提出亚单位重组传播阻断疫苗（TBV）作为成功消除和根除疟疾的有希望的疫苗。这里,一项临时研究旨在评估斯氏按蚊的丙氨酰氨基肽酶N（APN1）的免疫原性和功能活性，作为TBV候选人，用MPL管理，CpG,和QS21佐剂在小鼠模型中的应用。
结果：小鼠组用重组APN1（rAPN1）单独或与CpG配制，MPL,QS-21或佐剂组合（CMQ），并在第三次免疫后评估引发的免疫反应。标准膜饲喂测定（SMFA）测量了在将恶性疟原虫（NF54）传播至An时，佐剂化疫苗组中针对细菌表达的APN1蛋白的抗体的功能活性。Stephensi蚊子.用不同佐剂配制的rAPN1疫苗接种的小鼠的评估表明，抗APN1IgG和IgG亚类的高亲和力水平显着增加；然而，rAPN1诱导最高水平的高亲和力抗APN1IgG1，IgG2a，和免疫疫苗组5(APN1/CMQ)中的IgG2b抗体。此外,疫苗组5（接受APN1/CMQ），6个月后，相对于其他免疫组，抗APN1IgG抗体水平仍然最高，第180天SMFA数据表明在接受与CpG或三种佐剂的组合配制的抗原的组2和5中朝向更高的传播减少活性的趋势。
结论：结果表明混合物能够刺激针对靶抗原的高亲和力和持久抗体，以阻止疟原虫寄生虫在An中肠的发育。Stephensi.获得的结果验证了APN1/CMQ和APN1/CpG作为有效的基于APN1的TBV制剂,其将有助于将来设计疫苗。
结果：小鼠组用重组APN1（rAPN1）单独或与CpG配制，MPL,QS-21或佐剂组合（CMQ），并在第三次免疫后评估引发的免疫反应。标准膜饲喂测定（SMFA）测量了在将恶性疟原虫（NF54）传播至An时，佐剂化疫苗组中针对细菌表达的APN1蛋白的抗体的功能活性。Stephensi蚊子.用不同佐剂配制的rAPN1疫苗接种的小鼠的评估表明，抗APN1IgG和IgG亚类的高亲和力水平显着增加；然而，rAPN1诱导最高水平的高亲和力抗APN1IgG1，IgG2a，和免疫疫苗组5(APN1/CMQ)中的IgG2b抗体。此外,疫苗组5（接受APN1/CMQ），6个月后，相对于其他免疫组，抗APN1IgG抗体水平仍然最高，第180天SMFA数据表明在接受与CpG或三种佐剂的组合配制的抗原的组2和5中朝向更高的传播减少活性的趋势。
结论：结果表明混合物能够刺激针对靶抗原的高亲和力和持久抗体，以阻止疟原虫寄生虫在An中肠的发育。Stephensi.获得的结果验证了APN1/CMQ和APN1/CpG作为有效的基于APN1的TBV制剂,其将有助于将来设计疫苗。
