It's been a while I'm trying to isolate tumor-infiltrating lymphocytes from 4T1 mice tumor, but I haven't been successful so far. I already tried different tumor processing protocols, but all of them have resulted in a low yield of viable cells (Live Cells
For 4T1 mice tumor, a simple method is to remove the tumor, cut into pieces with a scalpel, and mash with the blunt side of a syringe, then pass through a 70um cell strainer. RBC lysis, lymphocytes can be isolated by flow cytometry. The Miltenyi kit is good, but I don't think it can solve the problem of cell death. In my opinion, tumor cells are dead in vivo, not because of the purification procedures.
You are welcome! Most of implanted tumor cells die because of apoptosis. You can confirm it with Trypan blue staining directly after taking out tumor and a gentle mash.