FIGURE 7.

β₂GPI-reactive CD4⁺ T cell clones derived from an autoimmune patient recognize the same peptide as H-2^b-bearing mice. β₂GPI-specific T cell clones OM9 (A) and OM13 (B) were evaluated for proliferative responses to GP-1 (Domains I and II), GP-2 (Domains III and IV), GP-3 (Domains IV and V), GP-F (full-length β₂GPI), or MalBP (control fusion protein) (20 μg/ml) or to peptides (10 μg/ml) covering the entire sequence of Domains I and II of β₂GPI using an in vitro T cell assay. MHC class II haplotype restriction of β₂GPI-specific T cell clones OM9 (C) and OM13 (D) was evaluated using a series of L cell transfectants expressing a single human HLA class II molecule in the presence or absence of peptide 23. Cells were incubated for 72 h, and cell proliferation was measured using [³H]thymidine incorporation. Values represent mean [³H]thymidine incorporation (cpm) ± S.E. of triplicate samples. The data shown are representative of two independent experiments. DMSO, dimethyl sulfoxide; Ag, antigen; EBV-B; Epstein-Barr virus-transformed B cells.