Engineering a patient’s own T cells to express tumor-targeting heterodimeric
T-cell receptors (TCRs) is a promising therapeutic strategy.
Even so, development of this method has been undermined by
unintended dimerization of endogenous and exogenous TCR chains,
resulting in hybrid receptors that lead to off-target effects and autoimmunity,
and by suboptimal expression of the introduced tumor-specific
TCR. Provasi et al. overcome these obstacles by first disrupting
the endogenous TCR a and b chains using zinc-finger nucleases.
Subsequent expression of tumor-targeting TCR chains delivered by
lentiviral vectors produced high levels of expression of the expected
antigen-specific TCRs. Tested in a series of experimental mouse models,
the engineered cells did not set off an auto-immune response
and protected the mice against leukemia. (Nat. Med. advance online
publication, doi:10.1038/nm.2700, 1 April 2012)