Eosinophil-specific biological activity of recombinant ovine interleukin-5.
Recombinant ovine interleukin-5 (rovIL-5) expressed from Chinese hamster ovary (CHO) cells was tested for cell-specific bioreactivity, in vitro, in a soft agar clonogenic assay and in an enzyme-based microassay for eosinophil potentiating activity (EPA). In soft agar assays, colony and cluster formation from sheep bone marrow cells (SBMC) incubated with rovIL-5 was significantly enhanced compared with SBMC incubated with control supernatants from mock-transfected CHO cells. Colony analysis at 14 days demonstrated that for three separate rovIL-5 preparations 45%, 61% and 66% of colonies were eosinophilic, as were 55%-71% of clusters. In contrast, no eosinophil colonies were detected in parallel control cultures. RovIL-5 was also shown to possess potent and dose-responsive EPA, on the basis of eosinophil peroxidase (EPO) and arylsulphatase (EAS) assay in 7 day SBMC cultures. This activity was inhibited in a dose-responsive manner by TRFK-5, a rat anti-murine IL-5 monoclonal antibody (MAb) previously shown to have cross-reactivity in the ovine EPA assay. The results demonstrate that rovIL-5 exhibited eosinophil-specific properties similar to those of IL-5 derived from other mammalian species.
Stevenson
L M
LM
Napier University, Edinburgh, Scotland, UK. l.stevenson@napier.ac.uk
McInnes
C J
CJ
Haig
D M
DM
Jones
D G
DG
D000362:Agar; D000818:Animals; D001854:Bone Marrow Cells / Q000187:drug effects; D016466:CHO Cells; D002478:Cells, Cultured; D002999:Clone Cells / Q000187:drug effects; D006224:Cricetinae; D004804:Eosinophils / Q000187:drug effects*; D007124:Immunoenzyme Techniques / Q000662:veterinary; D015848:Interleukin-5 / Q000494:pharmacology*; D051381:Rats; D011994:Recombinant Proteins / Q000494:pharmacology; D012756:Sheep
D015848:Interleukin-5; D011994:Recombinant Proteins; D000362:Agar