① ② Human recombinant TNF Spleen cells are isolated Anti-TNF Ab-producing plasma cell is isolated and ③ Antibody-producing the Ab-coding DNA sequence is purified human plasmacelle Genes Antibody Genes Antibody VL 8 CI CH3CH2 VH CHI CH3CH2 CHI Genes coding for human constant regions(CH,CL) and mouse variant regions (VH,VL)are combined Binds TNF