The TCR/CD3 complex represents the ligand for SLE serum IgG that is responsible for the increased expression of –180/protein complex formation. (A) Wild-type Jurkat T cells or J.EMS.T3.3 cells (a Jurkat T cell subline missing the TCR/CD3 complex) were treated with 1% normal or SLE sera for 3 hours, and nuclear extracts were subjected to a shift assay using the –180 oligonucleotide. (B) Cumulative data (n = 4) are shown. The y axis indicates relative densitometric units with the effect on TCR/CD3–positive cells set at 1. *P < 0.05. (C) Normal or SLE sera were adsorbed for 30 minutes at room temperature and another 30 minutes at 4–C on either Jurkat or J.EMS.T3.3 T cells and used to treat normal T cells for 3 hours. Nuclear extracts were subjected to a shift assay using the –180 oligonucleotide. (D) Cumulative data showing the effect of adsorption of SLE sera (n = 4) on TCR/CD3–positive and –negative Jurkat T cells. The y axis indicates relative densitometric units with the effect of sera adsorbed on TCR/CD3–positive cells set at 1. *P < 0.05. (E) SLE sera were adsorbed on TCR/CD3–positive and –negative cells, and the IgG fraction was isolated and used to treat normal T cells for 3 hours. Nuclear extracts were isolated and subjected to a shift assay using the –180 oligonucleotide. One of 2 similar experiments is shown.