Characterization of caprine interleukin-4

Caprine interleukin-4 (IL-4) cDNA was cloned from RNA of mitogen stimulated goat peripheral blood mononuclear cells utilizing reverse transcriptase-po lymerase chain reaction. The sequence of caprine IL-4 cDNA corresponds to a 535 nucleotide mRNA with 5'- and 3'-untranslated regions and a 405 nucleot ide open reading frame, the first 66 nucleotides of which encode a putative signal peptide. Mature IL-4 is a 12.8 kDa protein containing six cysteine residues and two potential N-linked glycosylation sites and is highly homol ogous with other ruminant IL-4. The predicted molecular mass of mature ungl ycosylated IL-4 was confirmed by western blot of recombinant caprine IL-4 e xpressed in bacteria with a monoclonal antibody against a carboxyterminal p eptide derived from the predicted amino acid sequence of bovine IL-4. Eukar yotic expression plasmids containing caprine IL-4 cDNA were used to charact erize recombinant IL-4. Transcription of IL-4 mRNA was confirmed by transfe ction of COS-7 and goat synovial membrane cells, and recombinant IL-4 produ ced by stably transfected L929 cells inhibited inducible nitric oxide synth ase in macrophages. Genetic immunization of mice with a caprine IL-4 cDNA e xpression plasmid induced antibodies against recombinant caprine IL-4 produ ced in bacteria. (C) 2001 Elsevier Science B.V. All rights reserved.