Expression of the synthetic human interleukin-10 gene and its mutant variants in Escherichia coli cells

The human interleukin-10 gene was obtained by chemico-enzymatic synthesis, and vectors for cytoplasmic and periplasmic expression of the recombinant IL-10 gene in Escherichia coli cells were constructed. Mutant IL-10 genes bearing substitutions in a region upstream of the ATG codon and in the triplet coding for the second amino acid residue in the protein were obtained by in vitro mutagenesis. High levels of expression were observed for the fusion protein composed of IL-10 and an N-terminal fragment of IL-3 and for the mutant IL-10 containing cystein as the second amino acid residue.