Title:Plasmodium falciparum Heat Shock Protein 70 Lacks Immune Modulatory Activity
Volume: 24
Issue: 6
Author(s): Ofentse Jacob Pooe, Gabriele Köllisch, Holger Heine and Addmore Shonhai*
Affiliation:
- Department of Biochemistry, School of Mathematical and Natural Sciences, University of Venda, Thoyoyandou,south africa
Keywords:
Plasmodium falciparum Hsp70, recombinant protein, immune modulation, lipopolysaccharide, TLR2, TLR4.
Abstract: Background: 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.
Objective: The current study sought to investigate the role of Plasmodium falciparum Hsp70
(PfHsp70) in immune modulation.
Method: 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.
Results: 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.
Conclusion: 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.
