The overexpression of OVA in CT26.WT-OVA tumor cells can improve the immunogenicity of tumor cells and be used for screening the efficacy of immuno-oncology (I/O) therapeutics.
 

Gene targeting strategy for CT26.WT-OVA cells. The coding sequence of chicken ovalbumin gene (SERPINB14) was transduced into CT26.WT cells by lentiviral.

OVA expression analysis in CT26.WT-OVA cells by flow cytometry. Single cell suspensions from wild-type CT26.WT and CT26.WT-OVA cultures were stained with species-specific anti-OVA antibody. OVA was detected on the surface of CT26.WT-OVA cells but not wild-type CT26.WT cells. The A4 clone of CT26.WT-OVA cells were used for in vivo experiments.

Subcutaneous homograft tumor growth of CT26.WT-OVA cells. CT26.WT-OVA cells (1x10⁵) and wild-type CT26.WT cells (1x10⁵) were subcutaneously implanted into BALB/c mice (female, 8-week-old, n=5). Tumor volume and body weight were measured twice a week. (A) Average tumor volume ± SEM. (B) Body weight (Mean ± SEM). Volume was expressed in mm³ using the formula: V=0.5 X long diameter X short diameter². As shown in panel A, CT26.WT-OVA cells were able to establish tumors in vivo and can be used for efficacy studies.

CT26.WT-OVA tumor cells growth of individual mice. CT26.WT-OVA cells (1x10⁵) and wild-type CT26.WT cells (1x10⁵) were subcutaneously implanted into BALB/c mice (female, 8-week-old, n=5). As shown in panel, CT26.WT-OVA cells were able to establish tumors in vivo and can be used for efficacy studies.

CT26.WT-OVA cells were subcutaneously transplanted into BALB/c mice. At the end of the experiment, tumor cells were harvested and assessed for OVA expression by flow cytometry. As shown, OVA was expressed on the surface of tumor cells.

Flow cytometry analysis of tumor infiltrating lymphocytes (TILs). Tumor cells were harvested in the end of the experiment. Flow cytometry analysis of the lymphocytes were performed to assess cell number and proportion changes compared to the wild-type CT26.WT. CD4+ T cells, CD8+ T cells and Treg cells were increased, and the ratio of CD8+ T cells were significantly increased compared to the wild-type CT26.WT. Therefore, CT26.WT-OVA cells can be used for in vivo efficacy studies of immuno-oncology (I/O) therapeutics. Values are expressed as mean ± SEM (P＜0.05).