A, T cell proliferation assay (MTT) demonstrating augmentation of proliferation when ttMo were cultivated with APC in comparison to baseline (baseline=endogenous proliferation of non‐stimulated cells, P=0.002, ANOVA with 2 repeated factors). Proliferation could be blocked by supplementation of anti‐MHC II (P=0.003, ANOVA with 2 repeated factors). This result indicates the dependence of MHC II receptor‐mediated tt antigen presentation by ttMo. B, Quantitative analysis of CD4+ T‐cell proliferation after co‐cultivation with ttMo in an in vitro CFSE assay compared to baseline (repeated measurement ANOVA, P=0.022); (C) Quantitative analysis of IL‐2 production in spleen‐derived T cells from immunized mice after stimulation with ttMo, neMo or co‐cultivation with pure tt. IL‐2 production increased after adding ttMo to an APC co‐culture in comparison to co‐culturing with neMo or supplementation of pure tt (P=0.002, ANOVA). This augmentation of IL‐2 production could be blocked completely when anti‐MHC II was added to the cell suspension (P=0.023). No significant difference in IL‐2 production was observed between pure tt and neMo groups (P=0.153 paired t test). The bar charts represent the results as the means±standard errors. The asterisks indicate significant pairwise comparisons (P<0.05, without α‐adjustment). ANOVA indicates analysis of variance; APC, antigen‐presenting cell; CFSE, carboxyfluorescein‐diacetate‐succinimidyl‐ester; IL, interleukin; MHC, major histocompatibility complex; MTT, 3‐[4,5‐dimethylthiazol‐2‐yl]‐2,5‐diphenyltetrazolium bromide; neMo, non‐engineered monocytes; ttMo, tetanus toxoid monocytes.