bispecific t cell engager 

BiTE only consists of the variable regions from distinct antibodies. It is expressed by transfected mammalian cells with four tandem variable regions connected by flexible peptides. One of its paratopes targets certain tumor-associated cell surface antigen, while the other binds CD3 so as to recruit T cells. Without Fc region, its samller size (~55 kDa) gives BiTE a short serum half-life, however, it also ensures a closer proximity to the surface of both T cell and target cell. BiTEs have more than thousands of times of efficiency in lysing tumor cell compared with other CD3-bispecific or IgG antibodies. Even with a concentration as low as 10 pg/ml in cell culture, BiTEs are still able to direct multiple rounds of target cell lysis by T cells with a low effector cell : target cell ratio. All of these properties have made it one of the most important T cell recruiters for cancer treatment and immune regulation.
https://www.creativebiolabs.net/Bispecific-T-cell-engager-BiTE.htm