CD4⁺ T-cell inhibition of LCL and lymphoma cell line outgrowth. HLA class II–matched and –mismatched LCLs and HLA-matched lymphoma lines L591, U266, and BJAB were seeded at doubling dilutions of 10⁴ to 300 cells/well either alone or with the addition of 10⁴ CD4⁺ T cells of LCL-specific clones N1c3, N1c9, and N1c1, respectively. In each case the efficiency of target cell outgrowth, scored at 3 to 4 weeks, is expressed as the minimum target cell seeding required for successful outgrowth from T cell–target cocultures (■) compared with target cells cultured alone (). Results are shown from a single experiment representative of several such assays.