Pooe Ofentse Jacob, Köllisch Gabriele, Heine Holger, Shonhai Addmore
Department of Biochemistry, Westville Campus, University of KwaZulu-Natal, Private Bag X54001, Durban 4000. South Africa.
Parasitology, Philipps University Marburg. Germany.
Protein Pept Lett. 2017;24(6):503-510. doi: 10.2174/0929866524666170214141909.
Heat shock protein 70 (Hsp70) family are conserved molecules that constitute a major part of the cell's protein folding machinery. The role of Hsp70s of parasitic origin in host cell immune modulation has remained contentious. This is largely due to the fact that several studies implicating Hsp70 in immune modulation rely on the use of recombinant protein derived from bacteria which is often fraught with lipopolysaccharide (LPS) contamination. For this reason, there is need to clarify the role of parasite Hsp70 in modulating host immune cells.
The current study sought to investigate the role of Plasmodium falciparum Hsp70 (PfHsp70) in immune modulation.
We expressed recombinant PfHsp70 using three bacterial expression hosts: E. coli XL1 Blue, E. coli ClearColi BL21 and Brevibacillus choshinensis, respectively. We further investigated the immunostimulatory capability of PfHsp70 by monitoring cytokine production by murine immune cells cultured in the presence of the protein.
Recombinant PfHsp70 produced using E. coli XL1 Blue expression host induced IL6 and IL8 cytokines. On the other hand, PfHsp70 produced in E. coli ClearColi and B. choshinensis expression systems was associated with no detectable traces of LPS and exhibited no immunomodulatory activity.
Our findings demonstrate that PfHsp70 does not possess immunomodulatory function. Furthermore, our study further confirm E. coli ClearColi and B. choshinensis as appropriate expression systems for the production of LPS-free recombinant protein.
热休克蛋白70（Hsp70）家族是保守分子，构成细胞蛋白质折叠机制的主要部分。寄生源Hsp70在宿主细胞免疫调节中的作用一直存在争议。这主要是因为一些涉及Hsp70免疫调节的研究依赖于使用源自细菌的重组蛋白，而这种蛋白常常受到脂多糖（LPS）污染。因此，有必要阐明寄生虫Hsp70在调节宿主免疫细胞中的作用。
本研究旨在探讨恶性疟原虫Hsp70（PfHsp70）在免疫调节中的作用。
我们分别使用三种细菌表达宿主：大肠杆菌XL1 Blue、大肠杆菌ClearColi BL21和嗜碱芽孢杆菌来表达重组PfHsp70。我们通过监测在该蛋白存在下培养的小鼠免疫细胞产生的细胞因子，进一步研究PfHsp70的免疫刺激能力。
使用大肠杆菌XL1 Blue表达宿主产生的重组PfHsp70诱导了IL6和IL8细胞因子。另一方面，在大肠杆菌ClearColi和嗜碱芽孢杆菌表达系统中产生的PfHsp70未检测到LPS痕迹，且未表现出免疫调节活性。
我们的研究结果表明PfHsp70不具有免疫调节功能。此外，我们的研究进一步证实大肠杆菌ClearColi和嗜碱芽孢杆菌是生产无LPS重组蛋白的合适表达系统。
