Figure 5

Antitumor effect of redirected AML patient-derived T cells against autologous AML blasts via hMSC-produced bsAb CD33–CD3 and surface presented 4-1BBL molecule. (a) 1 × 10⁵ AML patient-derived MNCs were cultured together with 48 h pre-seeded 1x10⁴ hMSCs. After 96 h of co-cultivation the percentages of surviving HLA-DR⁺ AML blasts and CD3⁺ T cells were determined respectively as proportions of all CD45⁺ cells by flow cytometry analysis. (b) Total AML blasts number after 24, 48 and 96 h of co-incubation was calculated. The average of surviving cells and the s.d. of triplets are shown for one representative donor out of three. (c) Total numbers of CD3^-CD123⁺HLA-DR⁺CD45⁺ AML blasts (left) and CD3⁺CD123^-HLA-DR^-CD45⁺ T cells (right) after 96 h of co-cultivation with or without control/bsAb- and 4-1BBL-expressing hMSCs are reported for three independent donors. Numbers of each subpopulation were calculated according to their relative percentages as determined by staining for specific cell surface markers. (d) Absolute autologous T-cell number was measured after 96 h and overall expansion of the cells in the presence of hMSCs was determined. Data are presented as means±s.d. from three different donors. Statistical significance was determined using one-way analysis of variance with Bonferroni multiple comparison test. *P<0.05; **P<0.01; ***P<0.001.