Mouse model of CMV lipopeptide vaccination.

Peptide A (see Table 2) without adjuvant or the CMVpp65_495-503 epitope, emulsified with the synthetic PADRE T_H epitope and incomplete Freund's adjuvant (IFA) were each injected s.c. into two separate transgenic HLA A2.1 mouse littermates. After twelve days, all mice were sacrificed, the spleens were removed, and a cell suspension was made. The immune spleen cells were restimulated twice in vitro at 7d intervals with peptide-pulsed syngeneic lipopolysaccharide-stimulated (LPS) blasts as described.^23,118  After 14d, the restimulated spleen cells were tested for recognition of the immunizing CTL epitope on T2 cells (CMVpp65 peptide) or endogenously presented epitope on CMV-infected HLA A^*0201-expressing fibroblasts (MRC-5+CMV) in a chromium release assay (CRA). As controls, an irrelevant peptide-sensitized T2 cell (p53 peptide), uninfected MRC-5 fibroblasts, and HLA-mismatched fibroblasts infected with CMV (CW+CMV) were also tested in the CRA. Data shown is representative of four mice immunized with either peptide, and spleen cells analyzed for CMV-specific immune response.