FIG. 1.
Characterization of human TH clones by RT-PCR. Single-cell cloning of human peripheral blood was performed as described in Materials and Methods. Presence of mRNA for IFN-γ and IL-4 in these clones was measured 7 days after antigen activation, using RT-PCR as described in Materials and Methods. (A) Clones isolated under TH1 conditions. Lane 1, IFN-γ; lane 2, IL-4; lane 3, GAPDH. Arrows indicate positions of cytokine standards. (B) Clones isolated under TH2 conditions. Lane 1, standard (STD) for IL-4 (427 bp); lane 2, standard for IFN-γ (459 bp) (Clontech). GAPDH (not shown) was used as a loading control.