Poster Presentation 50th Lorne Proteins Conference 2025

Enhancing the plasma half-life of broad-spectrum chemokine binding tick proteins by fusion to XTEN tags (#343)

Mikaela Bell 1 , Ram Bhusal 1 , Pramod Aryal 1 , Shankar Devkota 1 , Barbara Kemp-Harper 1 , Martin Stone 1
  1. Monash University, Clayton, VICTORIA, Australia

Evasins (EVA) are a family of chemokine binding anti-inflammatory proteins identified in the saliva of some species of ticks (1). EVA-ACA1001, EVA-P974 and EVA-AAM1001 have been identified as high affinity binders and potent inhibitors of various CC chemokines (2, 3), making them promising as potential treatments for inflammatory diseases. As evasins are small proteins (11-12 kDa) their half-life in vivo may be too short for therapeutic applications. Despite this, very little is known about their pharmacokinetics. To improve the half-life of evasins, we have successfully produced and purified fusion evasins using the XTEN fusion partner, a genetically-encoded analogue of polyethylene glycol (PEG) (4). XTEN is an unstructured polypeptide chain that can be produced at various lengths to scale the size and plasma half-life of the protein of interest. Here we describe the expression, purification, functional validation, and pharmacokinetic analysis of three different length XTEN fusion to our evasins of interest. By improving the pharmacokinetics of evasins, this research helps to overcome a significant challenge in their practical application as effective anti-inflammatory therapeutics.

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  2. 2. Bhusal RP, Aryal P, Devkota SR, Pokhrel R, Gunzburg MJ, Foster SR, et al. Structure-guided engineering of tick evasins for targeting chemokines in inflammatory diseases. Proceedings of the National Academy of Sciences. 2022;119(9):e2122105119.
  3. 3. Devkota SR, Aryal P, Pokhrel R, Jiao W, Perry A, Panjikar S, et al. Engineering broad-spectrum inhibitors of inflammatory chemokines from subclass A3 tick evasins. Nature Communications. 2023;14(1):4204.
  4. 4. Schellenberger V, Wang C-w, Geething NC, Spink BJ, Campbell A, To W, et al. A recombinant polypeptide extends the in vivo half-life of peptides and proteins in a tunable manner. Nature Biotechnology. 2009;27(12):1186-90.