Development and identification of a fully human single-chain variable fragment 29 against TSLP.

Thymic stromal lymphopoietin is a key initiator for inducing Th2-type inflammation and a potential therapeutic target for allergic disease. In the present study, the naive human antibody library was enriched using human thymic stromal lymphopoietin (hTSLP) as an antigen by phage display. Single clones were randomly picked from the enriched antibody library after three rounds of selection, and these were expressed for enzyme-linked immunosorbent assay (ELISA). The positive single-chain fragment variables (scFvs) determined by ELISA were further identified by Western blot, Biacore, and flow cytometry. After three rounds of phage display, 35% of the scFv clones were positive by ELISA and could bind well with hTSLP. Further identification revealed that scFv29 had satisfactory characteristics. The scFv29 was specific to hTSLP, and had no cross-reaction with hIL-33, hIL-4, and hIL-13. The scFv29 could bind to hTSLP in competition with the TSLP receptor and could also bind to mouse TSLP. Cellular experiments revealed that mTSLP could stimulate myeloid dendritic cell (DC) to mature, and scFv29 blocking could reduce the maturation rate of DC. These findings suggest that scFv29 could be used as a neutralizing antibody to block the signaling of TSLP, and this work provides the foundation for further study of the therapeutic roles of TSLP in allergic inflammation diseases.