To estimate the density of the tumor-specific CTLs needed to control the growth of B16 tumor cells, Budhu et al. [58] performed a series of experiments in which variable numbers of SIINFEKL peptide-pulsed B16 tumor cells and SIINFEKL-specific CTLs (activated OT1 CD8 T cells) were co-inoculated in collagen–fibrin gels, and the number of surviving tumor cells was calculated at different time points (see Figure A1 and the Materials and Methods Section for more details). Here, CD8A is linked to neoplasm.