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. Author manuscript; available in PMC: 2010 Apr 28.
Published in final edited form as: Sci Transl Med. 2010 Feb 3;2(17):17ra10. doi: 10.1126/scitranslmed.3000116

Figure 2. Monovalent CD28 antagonists block allorecognition but do not impede the function of Treg cells in vitro.

Figure 2

(A) Mixed-lymphocyte reaction using human (n=10), baboon (n=15) or macaque (n=9) PBMC. Black bars: mean ±SD in control conditions (mouse irrelevant IgG1). White bars: mean ± SD with 10 µg/ml sc28AT. (B) IL-2 secretion by Jurkat T cells stimulated with bacterial superantigen (staphylococcal enterotoxin E, SEE) and Raji B cells in the presence of sc28AT (n=8) or CTLA4-Ig (n=3). Results are expressed as percentage of IL-2 secretion observed in the absence of Ab (100%). (C) Suppressive activity of human Treg is not impeded by CD28 blockade. Tregs were added to CD4+CD25− T cells stimulated with allogeneic irradiated PBMC at the indicated ratio in the presence of 10µg/ml of CD28 or CTLA-4 blocking antibodies. Results are mean cpm ± SD of one representative assay out of 3. (D) Suppressive activity of human Treg pre-treated with CD28 or CTLA-4 blocking Ab. Treg were first cultured with allogeneic mature DC in the presence of sc28AT or anti-CTLA-4 Fab fragments (10µg/ml) for 18h, washed and assessed in a suppression assay. Results are mean cpm ± SD of a representative assay out of 3. *, ** and *** indicate a significant difference at p<0.05, 0.01 and 0.001, respectively.