Expression of Recombinant Rat Interleukin-13 (IL-13) and Generation of a Neutralizing Rat IL-13 Antiserum

Using baculoviral and bacterial systems, we expressed biologically active recombinant rat IL-13 and generated neutralizing rat IL-13 antiserum. Recombinant rat IL-13 produced by baculovirus-infected insect cells stimulated proliferation of TF-1 premyeloid cell line and induced expression of 15-lipoxygenase mRNA in human peripheral blood monocytes. Antiserum generated by immunizing a rabbit with recombinant bacterial rat IL-13 specifically inhibited TF-1 proliferation induced by baculoviral rat IL-13 but did not neutralize human IL-13 mitogenic activity. Western blotting with anti-rat IL-13 serum revealed a ∼12 kD protein band in supernatants of insect cells infected with recombinant baculovirus carrying the rat IL-13 cDNA. The availability of recombinant rat IL-13 and rat IL-13 antibodies should facilitate studying the role of IL-13 in rat models of human inflammatory disorders.