The isolation and sequence of sheep interleukin 4

A cDNA corresponding to sheep IL-4 has been isolated and sequenced. The cDNA was synthesized using PCR and oligonucleotides designed from conserved regions of IL-4 cDNA published sequences. The nucleotide and amino acid sequences of a sheep IL-4 cDNA are presented and compared with sequences from other species. At the nucleic acid level, the sheep cDNA shared 73 and 62% homology with human and mouse cDNA homologues, respectively, while comparisons at the amino acid level revealed 50% homology with human IL-4 and 33% with the mouse homologue. Total amino acid homology between these species was 27%.