Characterization of human genomic DNA sequences homologous to the interleukin 2 cDNA.

Southern blot analysis of human placental DNA under low stringency hybridization conditions revealed several DNA fragments hybridizable to the human interleukin 2 (IL-2) cDNA. Four phage clones carrying these IL-2 cDNA-like sequences were isolated and their structures analyzed. A DNA fragment derived from one of the clones gave the strongest hybridization signal. Sequence analysis of this fragment revealed the presence of a cluster of three DNA segments, i.e. 20 base pairs (bp), 57 bp and 18 bp in length and having about 85%, 80% and 83% homology to three different parts of the coding region of human IL-2 cDNA, respectively.