Fig. 6: Immunological memory response.

a Memory T cells were analyzed by ELISA for IFN-γ release in the culture supernatants of CD4⁺ T cells, isolated from the spleen of the experimental mice and co-cultured with BMDCs, pulsed with rT2544. Data represents mean( ± SD) of three independent experiments. b The percentages of T_EM (CD4⁺CD44^hiCD62L^lo) and T_CM (CD4⁺CD44^hiCD62L^hi) cells from the spleens of different experimental groups were quantified using flow cytometry. Representative images from one of the experiments and statistical analysis of the data from all three experiments are shown. c Serum antibody titers (mean ± SD) measured in the immunized mice (n = 6) at the indicated time points are shown. Arrows indicate primary (3 doses at 0, 12 and 24th day) and booster (108th day) immunization. Mean ± SD were plotted for CTB-T2544 and T2544. d Avidity assay. Anti-T2544 avidity index was measured by ELISA and represented as the ratio of IgG bound to T2544 in the presence and absence of 4 M urea, multiplied by 100. Significance was calculated using one way (a, d) and two-way (b) ANOVA with post hoc analysis using Tukey’s multiple comparison test. Error bars represent SD. ****p < 0.0001.