Protocol for intracardiac delivery and live imaging of NK-tumor interactions in an ex ovo chick embryo model

We present a protocol to evaluate natural killer (NK)-tumor interactions using an ex ovo chick embryo system. We describe procedures to culture GFP-labeled SH-SY5Y neuroblastoma cells, expand and Hoechst-label human NK cells, and perform sequential intracardiac injections. We use fluorescence imaging to visualize NK and tumor cell distribution in vivo and live imaging to assess interactions in vitro. This approach provides a rapid and accessible platform to quantify NK cell activity in a living vertebrate model.