A novel strategy for the negative selection in mouse embryonic stem cells operated with immunotoxin-mediated cell targeting.

Immunotoxoin-mediated cell targeting (IMCT) is a technique for conditionally ablating specific cell types based on the cytotoxic activity of a recombinant immunotoxin anti-Tac (Fv)-PE40. To examine the feasibility of this technique for the negative selection in mouse embryonic stem (ES) cells, we investigated the responsiveness of cells expressing human interleukin-2 receptor alpha subunit to anti-Tac(Fv)-PE40. The immunotoxin treatment efficiently eliminated only ES cells bearing the receptor as a consequence of the target specificity of anti-Tac(Fv)-PE40, indicating that IMCT can be used as a novel strategy for positive and negative selection to enrich ES cell clones with a targeted mutation.