Boosting cellular immune response through the CD28Apt7 dimer. (a) Detection of IFN-γ by Enzyme-Linked ImmunoSorbent Assay (ELISA) from supernatant obtained after a 48 h co-culture of irradiated A20 cells and lymphocytes obtained from mice previously immunized with irradiated A20 cells plus 400 pmol of the CD28Apt7 dimer, or CD28 agonistic antibody 37.51, or a scramble aptamer. The results are expressed as mean and SEM of triplicate experiments. (b) Detection of IFN-γ-producing lymphocytes through Enzyme-Linked ImmunoSpot Assay (ELISpot) after 24 h co-culture of irradiated A20 cells and lymphocytes obtained from mice previously immunized with irradiated A20 cells plus 400 pmol of the CD28Apt7 dimer, or CD28 agonistic antibody 37.51, or a scramble aptamer. The results are expressed as mean and SEM of triplicate experiments. (c) Detection of IL-2 by ELISA from supernatant obtained after a 48 h co-culture of irradiated A20 cells and lymphocytes obtained from mice previously immunized with irradiated A20 cells plus 400 pmol of the CD28Apt7 dimer, or CD28 agonistic antibody 37.51, or a scramble aptamer. The results are expressed as mean and SEM of triplicate experiments. * p < 0.05. IFN, interferon; IL, interleukin; NS, not significant. Reproduced from Pastor et al. [60].