Detecting treatment effects on intra-tumor immune cell populations using a syngeneic model of murine BRAF-mutant melanoma

To identify the immune cells in the tumor microenvironment specifically elicited by the regimen of anti-PD-L1 lead-in prior to MEKi combination, we sampled tumors (n=3-4/group) with vehicle or anti-PD-L1 (priming) treatments on day 7 and tumors (n=3-4/group) 3 days and 7 days after treatments in four regimens: (i) MEKi starting day 7, (ii) MEKi+anti-PD-L1 starting day 7, (iii) anti-PD-L1 day0-7, MEKi starting day 7, and (iv) anti-PD-L1 day0-7, anti-PD-L1+MEKi starting day 7.