Fig 6. MCMV.env immunization leads to induction of strong Env_123-141-specific CD4⁺ T cell responses.

CB6F1 mice were immunized with MCMV.env, or a non-transgene-encoding control MCMV, either once, or twice in a three-week time interval, and Env-specific immune responses were analysed in peripheral blood cells by MHC II tetramer staining two weeks after the first immunization (A) or five weeks after the first immunization (B). (C) Correlation analysis of Env-specific CD4⁺ T cells shown in (B) and viral loads in spleens of immunized mice shown in Fig 4D. (D) Two weeks after the first immunization, cytokine production of CD4⁺ T cells from peripheral blood was analysed after in vitro restimulation with a pool of Env-derived peptides. (A-C) Each dot indicates an individual mouse, columns indicate the mean values, dotted line indicates the detection limit, grey lines indicate the 95% confidence interval. (A) Data were obtained in two (MCMV) or five independent experiments (MCMV.env, unvaccinated), using 5 (MCMV), 9 (unvaccinated) or 21 mice (MCMV.env) per group. (B) Data were obtained in two (MCMV), three (MCMV.env_single,late) or five independent experiments (MCMV.env_twice, unvaccinated), using 4 (MCMV), 12 (MCMV.env_single,late) or 14 mice (unvaccinated, MCMV.env_twice) per group. (D) Data were obtained in one experiment; dots indicate mean values, whiskers indicate the standard deviation. Statistically significant differences compared to unvaccinated mice are indicated by * (P < 0.05, One Way ANOVA on Ranks, Dunn’s post test).