Development of human monoclonal antibodies against TARM1 by yeast display.

TARM1, a leukocyte immunoglobulin-like receptor expressed on myeloid cells, functions as a costimulatory receptor promoting proinflammatory cytokine secretion. Recent studies have revealed the involvement of TARM1 in immune-mediated diseases. Despite its biological importance, research tools for elucidating human TARM1 function have been limited. Here, we generated monoclonal antibodies (mAbs) against human TARM1 by a yeast display platform combined with a human single-chain variable fragment (scFv) library. Two scFv clones were isolated and converted into IgG1 antibodies, both of which bound recombinant TARM1 with high affinity and cell-surface TARM1. Importantly, these antibodies induced activation signals into Jurkat NFAT-GFP reporter cells expressing TARM1-CD28-4-1BB-CD3ζ chimera, indicating agonistic activity. These mAbs provide valuable tools for dissecting TARM1-mediated function and represent a potential approach for therapeutic strategies in inflammatory diseases and cancer.