Abatacept reduces T cell proliferation in vitro. (A-C) SFMC from RA patients (n=6) were sorted into CD4+CD25- T effector cells as well as CD4+CD25++ Treg and were co-cultured with CD3-APC for 6 days in the presence of plate-bound α-CD3, either in the presence or absence of 10 μg/ml abatacept. (A) Synovial CD4+CD25- T effector cells were cultured alone and in the presence of different ratios of CD4+CD25++ Treg. The graph depicts the percentage of suppression by CD4+CD25++ Treg in co-culture either in the absence (black line) or the presence of abatacept (grey line). A summary of six experiments is shown and all values are expressed as mean+SD. (B) The graph displays the suppression of proliferation at the 1:1 ratio of T effector cells and Tregs. (C) Proliferation of CD4+CD25- T effector cells alone was measured by thymidine incorporation in the absence or presence of abatacept (n=6). (D-F) SFMC from RA patients were stimulated with α-CD3 (white bars) or influenza vaccine (grey bars) in the presence of 10 μg/ml abatacept or a control compound. Proliferation of SFMC was measured by thymidine incorporation following 72 hours (α-CD3) or 6 days (influenza) in culture. All values are expressed as mean+SD. (D) All patients are displayed, (α-CD3: n=15 patients; Influenza: n=7). (E) Only ACPA-positive patients are displayed, (α-CD3: n=9 patients; Influenza: n=5). (F) Only ACPA-negative patients are displayed, (α-CD3: n=6 patients; Influenza: n=2).
Pieper et al. BMC Immunology 2013 14:34 doi:10.1186/1471-2172-14-34