FIGURE 6.

Effect of down-regulation of CD166 expression on recognition by 47-LDA-induced cellular responses in vitro (A and B) and in vivo (C and D). CTL activities of 47-LDA vaccine-induced CD8⁺ splenocytes in A/J mice against Neuro2a (A) and Neuro2a-cl number 1 (B) cells were analyzed in a standard ⁵¹Cr-release assay. CD8⁺ T cells from the sham plasmid-immunized mice were used as controls. All determinations were made in triplicate samples, and the SD was <10%. Results are presented as the means ± SD of three independent experiments. The effect of a prophylactic 47-LDA vaccine on Neuro2a (C) and Neuro2a-cl number 1 (D) tumor growth in A/J mice. Groups of A/J mice (n = 5) were immunized i.m. with the 47-LDA vaccine delivered in combination with IL-15 and IL-21 genes and injected s.c. with Neuro2a or Neuro2a-cl number 1 tumor (2 × 10⁶ cells per injection) 2 wk after the third booster immunization. Tumor-challenged mice that were immunized with the sham plasmid served as controls. Animals were examined daily until the tumor became palpable, after which tumor growth was monitored by measuring s.c. tumors once to three times a week.