Fig. 1

CCL2 enhances killing of 67NR cells but not 4 T1 cells by neutrophils. Tumor cells were seeded with and without neutrophils at a ratio of 30 neutrophils to 1 tumor cell in the absence and presence of CCL2. After 18-h incubation at 37 °C, cells were lysed and luciferase was measured to determine tumor cell killing. Luminescence was analyzed using the Kruskal-Wallis (KW) test with Dunn’s post-test if the KW test was statistically significant (p < 0.05). a & b Naïve as well as tumor entrained neutrophils were able to kill 4 T1 tumor cells (p = 0.002 and p < 0.001, respectively). c Naïve neutrophil killing of 67NR cells resulted in a p value of 0.058, but the addition of CCL2 resulted in a statistically significant killing of 67NR cells (p = 0.001) d. TEN were not capable of killing tumor cells, but addition CCL2 to TEN enhanced this effect in 67NR models (p-0.02 for 67NR + TEN vs. 67NR + TEN + CCL2, p = 0.004 for 67NR vs. 67NR + TEN + CCL2) Kruskal-Wallis test with Dunn’s test for multiple comparisons. Values are graphed as mean ± SD