Figure 2.
Combination treatment with alloDCs and an infection-enhanced adenoviral vector providing TAA results in efficient induction of endogenous TAA-specific T cells. (A) C57BL/6NRj mice were vaccinated s.c. in a prime (day 0) and boost (day 10) prophylactic setup with 5×109 evg of Ad5M(gp100) either alone or after transduction of 1×106 alloDCs. (B) Blood was collected one week later (day 17) and the presence of T cells (CD8a+CD3+) with a TCR for the human gp10025-33 epitope (gp100-TCR+) were analyzed with an H-2Db/hgp10025-33-PE tetramer in flow cytometry. Presence of gp100-TCR+ T cells was determined as positive if a distinct population above 0.5% of the parental CD8a+CD3 a+ population (cut off value for Ad5M(MOCK)) was observed. Shown is a chart with the number of mice with gp100-TCR+ T cells. (C, D, E) The vaccinated mice were then inoculated (day 18) with 2×105 Hcmel12 cells, derived from a primary HGF-CDK4(R24C) melanoma25 and tumor growth was monitored. Shown is a scatter plot representing the correlation of tumor size and % of gp100-TCR+ T cells at the time of the first recorded tumor-related death (day 40) for (C) all controls and treatments pooled (r = −0.3271, p = 0.0450), (D) mice treated with Ad5M(gp100) and control (r = −0.1256, p = 0.5681) and (E) mice treated with Ad5M(gp100)-alloDC and control (r = −0.5434, p = 0.0074). (F) For a therapeutic setting, C57BL/6NRj mice were inoculated with 5 ×105 Hcmel3 cells, another primary HGF-CDK4(R24C) melanoma with slower growth kinetics,26 and received three consecutive weekly i.t injections with 5×109 evg Ad5M(gp100) alone or after transduction of 1×106 alloDCs. Control mice were treated with 5×109 evg Ad5M(MOCK) or 1×106 alloDCs. (G) The presence of gp100-TCR+ T cells was evaluated by tetramer flow cytometry, one month after inoculation of tumors. (H) Scatter plot representing the correlation of tumor size and % of gp100-TCR+ T cells of CD3+ T cells (r = −0.5837, p = 0.0155) at the time of sacrifice.