Human xenograft treatment via 2G9-Salmonella bearing the HSV-TK enzyme. (A) Intracellular 2G9-Salmonella and empty vector-Salmonella measured 24 hours after intratumoral injection into mice bearing both CD20⁺ and CD20⁻ Karpas299 tumors. (B) Tracking of acute-phase tumor growth after a single intratumoral injection of the indicated bacteria into mice bearing both CD20⁺ Namalwa and CD20⁻ Karpas299 tumors (n = 8 mice per group). (C) Tracking of long-term Namalwa tumor growth coincident with the intratumoral administration of 2G9-AT-Salmonella (with or without HSV-TK), empty vector-Salmonella-HSV-TK, or PBS into mice bearing CD20⁺ Namalwa tumors, along with the intraperitoneal administration (twice daily) of either ganciclovir (100 mg/kg/day) or PBS. All data shown are taken from single experiments, which were representative of at least 2 separate experiments yielding similar results. (D) Actual cfus injected as determined after injection by limiting dilution assay of the injected bacterial solution, corresponding to the data presented in (C). (E) Tracking of Namalwa tumor growth after intravenous injection of 2G9-AT-HSV-TK (n = 7), 2G9-AT (n = 4), empty vector-AT-HSV-TK (n = 5), or PBS (n = 4) bacterial strains, along with intraperitoneal administration of ganciclovir. (F) Tracking of murine CD20+MCA203 fibrosarcoma tumors after intravenous administration following the same schedules or groupings as indicated in (E).