Induction of antigen-specific CTLs and antitumor effects of F37A in vivo.

(A–C) Mice immunized with F37A plus MPL (signal adjuvant) elicited a significant antigen-specific CTL in vivo. Mice were intradermally immunized three times with Peptide (free OVA SIINFEKL) or F37A, without and with MPL or CFA. The cytotoxicity of splenic T cells was measured using a standard 51Cr releasing assays (CTL assay) against E.G7-OVA cells or OVA-negative EL-4 cells at the target∶effector ratios indicated on the X-axis. Values are expressed as mean ± SD (n = 3). (D–F) Immunization with F37A plus MPL or CFA inhibited tumor growth in mice. Following immunization, E.G7-OVA cells (2×106 cells) were inoculated into the backs of mice (n = 8) and tumor volume was monitored. Each dot indicates the tumor volume in an individual mouse 3 weeks after tumor inoculation.