Figure 1.
Radiation decreases immunity generated by adenovirus encoding MART-1 cDNA transduced dendritic cells (AdVMART-1/DC). C57BL/6 mice were treated with 5 × 105 irradiated (10 Gy) or non-irradiated AdVMART-1/DC. A second immunization was performed 10 days later with 5 × 105 irradiated or non-irradiated AdVMART-1/DC. One week after the last immunization, MART-1-specific (a) interferon-γ (IFN-γ) and (b) interleukin-4 (IL-4) responses were assessed using enzyme-linked immunospot (ELISPOT) assays. Splenocytes were restimulated for 48 hr with EL4(MART-1) cells (black bars) or EL4 cells (white bars), or were not restimulated (control; grey bars). Mice immunized with AdVMART-1/DC that had been irradiated showed a reduced number of IFN-γ- and IL-4-expressing cells compared to those injected with non-irradiated dendritic cells. Furthermore, irradiated AdVMART-1/DC, whether given before or after AdVMART-1/DC, decreased their ability to generate responses. Results are shown as mean ± 1 standard error of the mean (SEM) of triplicate data of one representative of three independent experiments [*P< 0·05 compared with the EL4(MART-1)-restimulated group; **P< 0·0001 as compared with the AdVMART-1/DC-injected group].