The 7D12-5GS-6H4 bispecific VHH inhibits tumor growth in vivo. Immunodeficient BRGS mice grafted with SW480Gluc cells were treated with PBS (control group; (A), cetuximab (500 µg i.p.; group (B), Vγ9Vδ2-T cells (1*107 i.v.; group (C) or Vγ9Vδ2-T cells and 7D12-5GS-6H4 VHH (1*107and 1 µg, respectively, both i.v.; group (D) at days 1, 4 and 7. IL-2 (10,000 U, i.p.) was administered on days 1, 4, 7, 10, and 14 to the groups receiving Vγ9Vδ2-T cells. A) A schematic overview of the treatment schedule. B and C) Bioluminescence imaging at day 35 of 4 mice per treatment group. B) Heat map indicating the sites and relative level of tumor cell activity in individual mice. Red squares indicate the image field used for quantification analysis. C) Quantified bioluminescence signal measured per mouse expressed as the measured radiance normalized to the number of pixels, time and angle of imaging. Shown are means ± SEM of n = 4 mice per group. p-Values were calculated with a unpaired T-test (* indicates p<0.05). D) Kaplan-Meier analyses of mouse survival, n = 6 mice per group. p-Values were calculated with a Mantel-Cox test (* indicates p<0.05, ** indicates p<0.01 and *** indicates p<0.001). Abbreviations: Gly4Ser (GS).