Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran (PII), Pasteur Avenue, P.O. Box 1316943551, Tehran, Iran.
Trauma Research Center, Sina Hospital, Tehran University of Medical Sciences, Hassan Abad Square, Imam Khomeini Avenue, PO BOX: 1136746911, Tehran, Iran.
Malar J. 2020 Feb 19;19(1):79. doi: 10.1186/s12936-020-03154-3.
According to the World Health Organization reports, billions of people around the world are at risk for malaria disease and it is important to consider the preventive strategies for protecting the people that are living in high risk areas. One of the main reasons of disease survival is diversity of vectors and parasites in different malaria regions that have their specific features, behaviour and biology. Therefore, specific regional strategies are necessary for successful control of malaria. One of the tools that needs to be developed for elimination and prevention of reintroduction of malaria is a vaccine that interrupt malaria transmission (VIMTs). VIMT is a broad concept that should be adjusted to the biological characteristics of the disease in each region. One type of VIMT is a vector-based vaccine that affects the sexual stage of Plasmodium life cycle. According to recent studies, the aminopeptidase N-1 of Anopheles gambiae (AgAPN-1) is as a potent vector-based VIMT with considerable inhibition activity against the sexual stage of Plasmodium parasite.
Systems for rapid amplification of cDNA ends (3'-RACE) and genome walking methods were used for sequence determination of apn-1 gene from Anopheles stephensi and distinct bioinformatics software were used for structural analysis. AsAPN-1 was expressed in Spodoptera frugiperda (Sf9) insect cell line using the baculovirus expression system. Recombinant AsAPN-1 was purified under the hybrid condition and its biological activity was assayed.
Asapn-1 gene and its coded protein from An. stephensi were characterized for the first time in this study. Subsequently, the structural features and immunological properties of its coded protein were evaluated by in silico approaches. Enzymatic activity of the recombinant AsAPN-1, which was expressed in Sf9 insect cell line, was equal to 6 unit/μl.
Results of this study revealed that AsAPN-1 is very similar to its counterpart in An. gambiae. In silico evaluation and fundamental data which are necessary for its evaluation as a VIMT-based vaccine in the next steps were acquired in this study and those could be useful for research groups that study on malaria vaccine for countries that An. stephensi is the main malaria vector there.
根据世界卫生组织的报告，全球数亿人面临疟疾风险，因此考虑保护生活在高风险地区的人们的预防策略非常重要。疾病存活的主要原因之一是不同疟疾地区的媒介和寄生虫的多样性，它们具有特定的特征、行为和生物学特性。因此，需要制定特定的区域性策略来成功控制疟疾。消除和防止疟疾再次出现的工具之一是一种中断疟疾传播的疫苗（VIMT）。VIMT 是一个广泛的概念，应该根据每个地区疾病的生物学特征进行调整。VIMT 的一种类型是基于媒介的疫苗，它影响疟原虫生命周期的有性阶段。根据最近的研究，冈比亚按蚊的氨基肽酶 N-1（AgAPN-1）是一种有效的基于媒介的 VIMT，对疟原虫的有性阶段具有相当大的抑制活性。
使用快速扩增 cDNA 末端（3'-RACE）系统和基因组步行方法确定了来自斯氏按蚊的 apn-1 基因的序列，并使用不同的生物信息学软件进行结构分析。使用杆状病毒表达系统在 Spodoptera frugiperda（Sf9）昆虫细胞系中表达 AsAPN-1。在混合条件下纯化重组 AsAPN-1，并测定其生物学活性。
本研究首次对斯氏按蚊的 asapn-1 基因及其编码蛋白进行了特征描述。随后，通过计算机方法评估了其编码蛋白的结构特征和免疫特性。在 Sf9 昆虫细胞系中表达的重组 AsAPN-1 的酶活性等于 6 单位/μl。
本研究结果表明，AsAPN-1 与冈比亚按蚊非常相似。在本研究中获得了作为基于 VIMT 的疫苗进一步评估所需的计算评估和基本数据，这些数据对于研究冈比亚按蚊是主要疟疾媒介的国家的疟疾疫苗的研究小组可能有用。
