Parameters related to the application of recombinant ovine interleukin-1β as an adjuvant

This paper describes aspects of the safety and efficacy of recombinant ovine interleukin-1β (rovIL-1β) as an immunological adjuvant. A dose-response relationship was established using the intramuscular route, and significant adjuvant activity was observed following delivery of 10 or 100 μg of the cytokine delivered either in PBS or in combination with alum. Similar doses of rovIL-1β also showed adjuvant activity when delivered via the subcutaneous route. In experiments in both mice and sheep, rovIL-1β-mediated adjuvant activity was neutralised by a monoclonal antibody (mAb), 3.41, confirming that the adjuvant effect was due to the biological activity of the cytokine. Serum clearance rates and physiological responses to intravenous, intramuscular or subcutaneous administration of rovIL-1β in sheep were also determined. RovIL-1β was shown to have a serum half-life of 2 min. Transient body temperature increases of 2°C following intravenous or subcutaneous delivery, or 1°C following intramuscular delivery, were observed. White blood cell counts also fluctuated post-injection, which was shown to be due to changes in the number of circulating neutrophils. The action of the neutralising mAb on serum clearance, body temperatures and white cell counts was also determined. Co-injection of rovIL-1β with the mAb 3.41 prevented rapid clearance of the cytokine from the serum, and was associated with an extension in elevated body temperature. The mAb appeared to have no significant influence on the white blood cell profile induced following injection with rovIL-1β.