Genetic Immunization with CDR3-Based Fusion Vaccine Confers Protection and Long-Term Tumor-Free Survival in a Mouse Model of Lymphoma

Figure 2

Immune responses elicited after pTTV_HCDR3 and pTT immunizations. Humoral immunity was assayed by ELISA for mice sera V_H peptide (D₁₀₁-L-₁₂₂) reactive antibodies 3 weeks after priming (a) and 2 weeks after boosting. (b) Unimmunized mice represent the control group. Each marker indicates a value from a single mouse; group means are represented by a horizontal bar. Experimental groups (pTTV_HCDR3 group, 𝑛 = 7; control groups, 𝑛 = 6) were compared by unpaired, two-tailed t-test. (c) The frequency of IFN-γ-positive CD8⁺ T cells was assessed ex vivo by intracellular cytokine staining. Splenic lymphocytes were harvested 1 week after booster injection, stimulated with V_H peptide (D₁₀₁-L-₁₂₂), and assayed for IFN-γ production on gated T lymphocytes. Representative flow cytometric plots from pooled mice (3 animals/experimental groups) splenocytes are shown. Numbers in FACS plots refer to CD8⁺ IFN-γ ⁺ cells as a percentage of the total T cells population. (d) Data were pooled from two identical independent experiments to indicate the mean percentage of CD8⁺ T cells producing IFN-γ in response to V_H peptide. An 𝑋² test for the comparison of the two proportions, expressed as a percentage, was performed. Error bars: SEM. ^(*) denotes a statistically significant value (𝑃<.0001).

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