In Vitro and In Vivo Comparison of Lymphocytes Transduced with a Human CD16 or with a Chimeric Antigen Receptor Reveals Potential Off-Target Interactions due to the IgG2 CH2-CH3 CAR-Spacer

Figure 6

Immunohistochemical analysis of BT474 tumor sections. NK-92 were directly stained with CSFE and tumor cells were visualized by counterstaining with DAPI. (a) NK- and NK- could be found in different parts of the tumors, either as a cluster or as single cells and preinjection of trastuzumab did not affect NK- frequency within the tumor (panels 2 and 3). Panel 4 shows the absence of NK- within the tumors. (b) Comparison of effectors spreading between NK- and NK- within the tumors using direct CFSE visualisation (green): NK- appeared clustered at the edge of the tumor only whereas NK- are observed everywhere in the tumor. (c) Merge colocalization (yellow arrow) of mice macrophages (red) using Iba1 staining and NK- cells (green) are always located at the edge of the tumor (blue) whereas isolated macrophages (red arrow) can be found everywhere within the tumor. This was not observed with NK-. Typical representative images are presented.

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(b)

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