Antibody constructs for FLT3 and CD3

A bispecific antibody construct comprising a first binding domain which binds to human and macaque Fms-like tyrosine kinase 3 (FLT3) on the surface of a target cell and a second binding domain which binds to human CD3 on the surface of a T cell, wherein the first binding domain comprises a VH region comprising CDR-H1, CDR-H2 and CDR-H3 and a VL region comprising CDR-L1, CDR-L2 and CDR-L3, wherein said CDR-HI, CDR-H2, CDR-H3, CDR-LI, CDR-L2, and CDR-L3 comprise the amino acid sequences selected from the group consisting of:

• SEQ ID NOs:
• 181-186, SEQ ID NOs:
• 201-206, SEQ ID NOs:
• 211-216, SEQ ID NOs:
• 221-226, SEQ ID NOs:
• 251-256, SEQ ID NOs:
• 261-266, SEQ ID NOs:
• 281-286, SEQ ID NOs:
• 291-296, SEQ ID NOs:
• 301-306, SEQ ID NOs:
• 311-316, SEQ ID NOs:
• 331-336, SEQ ID NOs:
• 341-346, SEQ ID NOs:
• 431-436, SEQ ID NOs:
• 451-456, SEQ ID NOs:
• 461-466, SEQ ID NOs:
• 471-476, SEQ ID NOs:
• 491-496, SEQ ID NOs:
• 531-536, SEQ ID NOs:
• 541-546, SEQ ID NOs:
• 561-566, SEQ ID NOs:
• 591-596, SEQ ID NOs:
• 611-616, SEQ ID NOs:
• 631-636, and SEQ ID NOs:
• 701-706.