Figure 2.
Systemic delivery of mixed leukocytes ex vivo pre-loaded with TNF-armed MYXV as compared to i.v. infusion of free virus
(A) Diagram of experimental setup. BALB/c mice had K7M2-Luc cells implanted at day 0 via i.v. injection. Single dose systemic infusion with vMyx-hTNF (MYXV-TNF), either as free “naked” virus, after pre-loading ex vivo onto BALB/c PBMC carrier cells, or after pre-loading ex vivo onto BALB/c BM leukocytes was at 3 days after tumor inoculation. Animals were then followed for 100 days. (B) Kaplan-Meier survival curves of animals treated with three doses of PBMCs loaded ex vivo with vMyx-hTNF: 1 × 106 (n = 10), 2 × 106 (n = 10), and 4 × 106 (n = 10) PBMCs, each loaded with an MOI of 10 ffu/cell each. Each cell/virus dose level treatment led to a similarly significant increase in mean survival time over untreated controls (n = 5). (C) Scatterplot showing individual luminescence signals at 5 weeks after tumor inoculation. Animals treated with 2 × 106 and 4 × 106 PBMCs loaded with vMyx-hTNF had significantly smaller tumor luminescence signals than did untreated animals. (D) Representative luminescence images from 2 and 5 weeks after tumor inoculation of animals left untreated (i and iii) or treated with 4 × 106 PBMCs loaded with vMyx-hTNF. (E) Kaplan-Meier plot comparing a single dose of BM- versus PBMC-based ex vivo loading of vMyx-hTNF. Both treatments led to a significant increase in mean survival compared to untreated animals but were not significantly different from each other. (F) Kaplan-Meier plot comparing a single dose of PBMC-loaded vMyx-hTNF to a single systemic infusion of the identical dose (2 × 107 infectious units) of free (naked) vMyx-hTNF. Both treatments led to a significant increase in mean survival time; however, the single dose PBMCs+vMyx-hTNF led to a significant further increase in mean survival time when compared to systemic i.v. infusion of a single dose of naked virus.