Fig. 2.

A cDNA clone isolated from the 1869 cDNA library encodes an antigen recognized by C111 T cells. The 293 cells expressing the MHC DRβ1*0402 or 1301 molecules were transfected with the 1D8 cDNA clone, or COA-1a, which corresponds to nucleotides 209-1318 of the COA-1 gene (Fig. 3). Target cells were either transfected with the COA-1a product alone or were cotransfected with a mixture of COA-1a and the full-length HLA class II Ii. Additional targets were transfected with a control plasmid encoding green fluorescent protein. Eighteen h after the addition of 5 × 10⁴ C111 T cells to the transfectants, supernatants were collected and IFN-γ release was measured by ELISA.