Fig. 6.

Expanded Dog NK Cells Persist in the Tumor Microenvironment post Intra-tumoral Injection. a. Flow cytometry pre- (Left) and post (Right)-NK isolation and expansion demonstrates a significant depletion of CD3 and CD4 cells with a residual CD3+ population after 14-days in co-culture of approximately 10% consistent with minimal T cell contamination despite the positive expression of CD8. Flow cytometry staining is shown from patient #10. b. Using Cell Proliferation Dye Cell Tracker Red (eFluor® 670), we labelled NK cells prior to intra-tumoral injection in patient #10. Analysis of PBMCs 1 week following NK transfer shows near uniform staining of ex vivo labelled cells (Left) but no evidence of recovery of labelled 7AAD-CD45 + AF647+ NK cells in the peripheral blood. c. In the same patient (#10) tumor biopsy 1 week following NK transfer shows recovery of (Left) 7AAD-CD45+ and (Right) labelled 7AAD-CD45 + AF647+ NK cells, indicating persistence of adoptively-transferred NK cells in the tumor microenvironment. Representative flow cytometry data of NK labelling injections from 3 patients are shown