Epitope-specific CD4⁺ and CD8⁺ T-cell activation in peptide-immunized HLA-A*0201 transgenic mice.

Splenocytes were isolated on day 17 from mice immunized twice subcutaneously with the peptides 3, 13, 14, 17, 23, or vehicle at day 0 and day 10. The splenocytes were labeled with CFSE and cultured in the presence or absence of 10 µg/mL of the respective peptides for 8 days. Proliferation of CD4⁺ (A) or CD8⁺ (B) lymphocytes in response to the different CD8 epitopes was analyzed by flow cytometry using anti-CD4 or CD8 antibodies conjugated with PE-Cy5. Results are presented as cell division index (CDI) as described in the Materials and Methods. (C) The splenocytes were stimulated in vitro with or without the peptides and were stained with anti-CD8 antibody conjugated with FITC, and then fixed and stained for intracellular IFN-γ using PE-conjugated anti-IFN-γ antibody. The percentage of CD8⁺ IFN-γ⁺ T cells was calculated. *(p<0.05) and **(p<0.01) indicate they are significantly different from the unstimulated splenocytes. Data is representative of results derived from three independent experiments.