The development of bispecific antibodies that redirect the cytotoxic activity of CD3+ T cells against tumors is a promising immunotherapy strategy for hematological malignancies and solid tumors. The discovery and development of novel anti-CD3 antibodies are key to the efficacy and safety of the bispecific antibodies. Camelid-derived nanobodies have significant potential in bispecific antibodies as T cell engagers due to their small size, low production cost, high stability, and antigen specificity.
In this study, we identified variable nanobodies specific for the CD3 by immunizing a Vicugna pacos (alpaca) with recombinant human CD3 epsilon domain. In particular, the anti-CD3 Nb 1D10 clone showed a moderate affinity with recombinant human and Macaca fascicularis (cynomolgus monkey) CD3 and binding to CD3+ cell lines. These results highlight the potential of the nanobody for the development of nanobody-based bispecific antibodies as a T cell engager.