Construction of genetically modified lactic acid bacteria producing an Anti-Interleukin-31 receptor A Single-chain...

Nemolizumab, which targets the receptor for interleukin-31 (IL-31R), was approved in Japan in 2022 as a therapeutic antibody agent for atopic dermatitis. IL-31 is a cytokine involved in skin inflammation and pruritus, and recent studies have shown that it is also involved in pulmonary and respiratory diseases. Although antibody therapies such as nemolizumab have proven effective, their drug delivery methods remain suboptimal. Thus, in this study, we attempted to establish a novel local delivery system for IL-31Ra single-chain variable fragment (scFv) using recombinant lactic acid bacteria with the goal of enhancing the value of nemolizumab for future application to respiratory diseases.

The genetically modified lactic acid bacteria (gmLAB) constructed by electroporation was confirmed by Western blotting to produce recombinant scFv in a nisin-dependent manner. The binding of the recombinant scFv to its target protein, human IL-31Ra, was verified by ELISA. Furthermore, in vitro assay using A549 cells, the purified recombinant scFv was found to significantly inhibit signal transducer and activator of transcription (STAT3) phosphorylation induced by IL-31 stimulation.

We successfully constructed a novel tool for expressing IL-31Ra scFv designed based on nemolizumab using gmLAB. The scFv produced by gmLAB specifically bound human IL-31Ra and suggesting that it inhibits IL-31/IL-31Ra signaling. Taken together, our results suggest that the gmLAB established in this study may represent an efficient and convenient new tool for administering IL-31Ra scFv, with potential application to pulmonary and respiratory diseases.