Cloning, expression and biological activity of equine interleukin (IL)-5

F. M. Cunningham, E. Vandergrifft, S. R. Bailey, M. F. Sepulveda, N. T. Goode, D. W. Horohov

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


The cytokine, interleukin (IL)-5 stimulates eosinophil differentiation, activation and survival and can prime these cells, increasing the response to other mediators. In view of its many effects on eosinophils, IL-5 has been implicated in the pathogenesis of allergic disease in man. Here we report the cloning of equine IL-5 and expression of the recombinant protein by transfection of Chinese hamster ovary (CHO) cells. The cloned cDNA sequence consisted of 405 nucleotides and encoded a protein of 135 amino acids. There is >85% identity with feline, bovine, ovine, canine, and human IL-5 sequences at the nucleotide and protein level. Supernatants containing equine IL-5 were also examined for biological activity. CHO supernatant containing equine recombinant (eqr) IL-5, like the human ortholog (hrIL-5), induced concentration dependent equine eosinophil adherence to autologous serum-coated plastic (9.7±1.5% with a 1:100 dilution of eqrIL-5 and 9.1±1.6% adherence with 1nM hrIL-5; n=4). The eqr protein also caused concentration dependent superoxide production (11.9±2.4nmol {reduced cytochrome (cyt) C}/10 6 cells at a 1:50 dilution, n=4). In contrast, hrIL-5 only caused significant superoxide production when diluted in conditioned CHO medium, an effect that was inhibited by the anti-human mAb, TRFK5 (4.4±0.3 versus 0.3±0.4nmol/106 cells for 0.5nM hrIL-5 in the presence of the isotype matched IgG1 control (10μM) and TRFK5 (10μM), respectively). TRFK5 also significantly inhibited hrIL-5 induced adherence at concentrations of 0.3μg/ml and above but had no significant inhibitory effect on either superoxide or adherence caused by eqrIL-5. These results demonstrate that equine IL-5 expressed by CHO cells stimulates equine eosinophils, suggesting that this cytokine could play a role in eosinophil recruitment and activation in equine allergic disease. The anti-human and murine moAb TRFK5 does not appear to recognise the equine protein.

Original languageEnglish
Pages (from-to)63-72
Number of pages10
JournalVeterinary Immunology and Immunopathology
Issue number1-2
StatePublished - Sep 15 2003

Bibliographical note

Funding Information:
We are grateful to the Home of Rest for Horses (MFS, SB) and Equine Health Studies Program (LSU) for financial support.


  • Adherence
  • Eosinophil
  • Horse
  • Interleukin (IL)-5
  • Superoxide

ASJC Scopus subject areas

  • Immunology
  • Veterinary (all)


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