Expression of cytolytic mediators in alloantigen-specific human CD4⁺ and CD8⁺ CTLs. Expression of messenger RNAs (mRNAs) for perforin, granzyme B, and Fas ligand was investigated by RT-PCR. The mRNAs were extracted from CD4⁺clone #1-1 (lane 1), CD4⁺ clone #3-1 (lane 2), CD8⁺ clone #2-1 (lane 3), CD8⁺ clone #4-1 (lane 4), and a negative control B-cell line (lane 5). Lane M shows 100-bp ladder markers.