DEAD-box proteins, like Leishmania eIF4A, modulate interleukin (IL)-12, IL-10 and tumour necrosis factor-alpha production by human monocytes

• Published in: Parasite immunology 2013-06, Vol.35 (5-6), p.194-9
• Main Authors: Barhoumi, M., Meddeb-Garnaoui, A., Tanner, N. K., Banroques, J., Kaabi, B., Guizani, I.
• Format: Article
• Language: English
• Subjects: Life Sciences
• ISSN: 0141-9838; 1365-3024
• DOI: 10.1111/pim.12026

Previously we showed that His-tagged, recombinant, Leishmania infantum eukaryotic initiation factor (LeIF) was both an RNA-dependent ATPase and an ATP-dependent RNA helicase in vitro, as described for other members of the DEAD-box helicase family. In addition, we showed that LeIF induces the production of IL-12, IL-10, and TNF-α by human monocytes. This study aims to characterize the cytokine-inducing activity in human monocytes of several proteins belonging to the DEAD-box family from mammals and yeast. All tested proteins contained the 11 conserved motifs (Q, I, Ia, GG Ib, II, III, IV, QxxR, V and VI) characteristic of DEAD-box proteins, but they have different biological functions and different percentages of identities with LeIF. We show that these mammalian or yeast recombinant proteins also are able to induce IL-12, IL-10 and TNF-α secretion by monocytes of healthy human subjects. This cytokine-inducing activity is proteinase K sensitive and polymyxin B resistant. Our results show that the induction of cytokines in human monocytes is not unique to the protein LeIF of Leishmania, and it suggests that the activity of certain DEAD-box proteins can be exploited as adjuvant and/or to direct immune responses towards a Th1 profile in vaccination or immunotherapy protocols.