Research Paper Volume 14, Issue 5 pp 2131—2147

Figure 3. Activated primary NK cells selectively eliminate senescent cells. (A) Quantitative Realtime PCR was performed to detect the mRNA levels of CCL5, CXCL9, and CXCL11 in non-senescent and senescent IMR-90 fibroblasts. The results are presented as mean fold change in NS compared to S samples from two independent experiments performed in triplicate, and error bars represent ±SEM. Statistical analysis performed using unpaired t test. *p < 0.05, **p < 0.01, and ***p < 0.001. (B) NS or S IMR-90 fibroblasts were co-incubated with NK cells for 16 h at T:E ratios of 1:1, 1:2 and 1:3 and cytotoxicity was evaluated by LDH release. The graphs show the mean and S.E. of % LDH release. NS or S (C-i) doxorubicin-treated (n=6), (C-ii) irradiated (n=3) or (C-iii) etoposide-treated (n=3) IMR-90 fibroblasts or (C-iv) doxorubicin-treated endothelial cells (n=2) were overlayed with NK cells for 16 hours at T:E ratio of 1:1, and cytotoxicity was evaluated by LDH release. The results are plotted as mean % cytotoxicity for NS and S cells with each experiment performed in at least triplicate. The graphs show mean % LDH release. (D) NK cells isolated and enriched from three different individuals were co-cultured with NS or S IMR-90 cells at T:E ratio of 1:1 and cytotoxicity was evaluated by LDH release after 16 hours of co-culture. Experiments were performed in triplicate and the results are plotted as mean % cytotoxicity for NS and S. Donor sex and age are indicated in the figure. Statistical analysis performed using unpaired t test. *p < 0.05, **p < 0.01, and ***p < 0.001.