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. Author manuscript; available in PMC: 2017 Nov 1.
Published in final edited form as: Clin Cancer Res. 2016 May 23;22(21):5229–5237. doi: 10.1158/1078-0432.CCR-15-2971

Figure 4. Panitumumab activates CD32 receptors on monocytes to a greater degree than cetuximab but does not induce ADCC against HNSCC cells.

Figure 4

Surface activation markers, CD32 (A) and CD80, CD86 (B) of isolated monocytes (CD14+ positive selection) co-cultured with JHU029 and PCI15B HNSCC cells and treated with 10 μg/mL of cetuximab, panitumumab or isotype controls (IgG1 or IgG2) for 72h were measured by flow cytometry. Monocytes treated with panitumumab activate surface CD32 to a greater extent than those treated with cetuximab as demonstrated by downregulation of surface CD32. There is no significant difference in CD80 or CD86 expression on monocytes treated with cetuximab or panitumumab. (C) CD14+ cells co-cultured for 4h with 51Cr labeled JHU-029 HNSCC cells coated with 10 μg/mL of cetuximab, panitumumab or isotype controls (IgG1 or IgG2) at different E:T ratios (5:1, 10:1 and 20:1). Results demonstrate that monocytes did not mediate ADCC above isotype controls in the presence of either cetuximab or panitumumab. Data are mean + SEM,*p<0.05 cetuximab compared with panitumumab.