Colorectal Cancer Cell Line for In Vivo Studies

The BALB/cJ CT26 colorectal cancer cell line expressing GUCY2C and luciferase^{19 (link)} was used for in vivo tumor studies. For most studies, six days after final immunizations, mice received 5 × 10⁵ CT26 cells via intravenous (i.v.) tail vein injection. However, for memory studies, tumor challenges occurred 63 days after the final immunization. Tumor burden was quantified by subcutaneous injection of 3.75 mg of D-luciferin potassium salt (Gold Biotechnologies) in PBS followed by an eight-minute incubation and imaging with a ten-second exposure using a Caliper IVIS Lumina XR imaging station (PerkinElmer). Total radiance (photons/second) was measured using Living Image In Vivo Imaging Software (PerkinElmer).