Figure 1

In vitro expression and activity of CTLA4IgG. (A) In vitro expression of CTLA4IgG was detected by western blot of media from AAV2-CTLA4 transfected cells (lane 3). As a control, purified recombinant mouse CTLA4/Fc was also run on the gel (lane 2). (B) Biological activity of CTLA4IgG, based on its ability to bind and block B7.1, was determined by incubating with either medium from naïve HEK-293T cells (column 1) or from cells transfected with AAV2CTLA4 (column 2). Unbound B7.1 was then tested by flow cytometry using an antibody to B7.1. Data shown is mean from three independent experiments (asterisk, P = 0.0400). Unpaired student-t test was used in this analysis.