Given the important role of CTLA4 in regulating T-cell activation and enhancing antigen-presenting capacity, researchers have combined the CTLA4 immunoglobulin variable region (IgV_CTLA4) with novel multiepitope vaccine proteins to develop a new vaccine against brucellosis, and this vaccine demonstrates superior immunogenicity and antigenicity both in vitro and in vivo [35]. This evidence concerns the gene CTLA4 and brucellosis.