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78 | Chapter 3 further borne out by observed degranulation levels of NK cells in response to exposure to the cervical cancer cell lines, as measured by CD107a surface expression. These were comparably and significantly elevated in the PBNK + CET and UCB-NK conditions over PBNK alone (Figure 2c, Supplementary Figure 2). UCB-NK were not tested in combination with CET due to their low surface expression of CD16a, which is essential for ADCC in combination with therapeutic mAbs (data not shown). Interestingly, PBNK degranulation levels were low Figure 2: PBNK and UCB-NK cytotoxicity against cervical cancer cells (a) Cytotoxicity levels (∆7AAD) of PBNK (open bars) and UCB-NK (hatched bars) against ten cervical cancer cell lines. Bars are means of triplicate values from four experiments with four different donors for C33A, HeLa, SiHa, CC11B, CC11A, CC10B, CC10A, CaSki and two experiments with two different donors for CSCC7 and CC8 using PBNK and five experiments for UCB-NK using five different donors for all cell lines; Bars represent mean ± SEM. PBNK data used to compare with UCB-NK in Figure a are the same dataset as Figure 1a. (b) Significantly higher cytotoxicity levels (∆7AAD) were observed in all cell lines after co-culture with UCB-NK compared to PBNK. (c) Significantly higher levels of NK degranulation (∆CD107a) in PBNK + cetuximab (CET) and UCB-NK conditions compared to PBNK only condition. Triangles denote cell lines with low EGFR levels, i.e. C33A, HeLa, and SiHa. *P <0.05, **P < 0.01 and ***P < 0.001 calculated in A and B with unpaired t test, in C with one-way ANOVA, Bonferroni’s multiple comparison test.