CLONING, SEQUENCING AND EXPRESSION OF THE OVINE INTERLEUKIN-6 GENE

Gene amplification by reverse transcriptase PCR with heterologous primers has been used to obtain a cDNA clone encoding the structural sequences of ovine interleukin 6 from alveolar macrophages. This cDNA encodes a protein of M(r) = 23 429, which is 53% homologous in amino acid sequence to human IL = 6, The clone hybridizes to an RNA of size 1260 nt in alveolar macrophages, expression of which is potentiated by LPS, The ovine IL-6 structural gene has been cloned into the yeast expression vector pOGS40, and used to produce a recombinant protein, This protein is capable of causing increased immunoglobulin production in pokeweed mitogen stimulated ovine peripheral blood mononuclear cells at concentrations of 10-100 ng/ml, but it only causes very limited replication of B9 cells, a murine IL-6 dependent cell line, This is in contrast to recombinant human IL-6, which is capable of stimulating B9 cell proliferation, but not immunoglobulin production by ovine PBMC.