An antiserum against Atlantic salmon IFNa1 detects IFN and neutralizes antiviral activity produced by poly I:C stimulated cells

Abstract

Type I interferons (IFNs) play a crucial role in innate immune responses against virus infections in vertebrates. Two IFNs (IFNa1 and IFNa2) have previously been cloned from Atlantic salmon. In the present work a polyclonal antiserum, which was generated against salmon IFNa1 was used to study its production in cells by immunoblot detection and neutralization of antiviral activity. The antiserum was first confirmed to detect and neutralize the antiviral activity of recombinant salmon IFNa1 produced in HEK293 cells. The antiserum also detected IFNa1 and neutralized 95-98% of the antiviral activity in supernatants of poly I:C stimulated salmon TO cells. This suggests that IFNa1/IFNa2 are the major IFNs produced by poly I:C stimulated TO cells. The antiserum neutralized most of the IFN activity in poly I:C stimulated head kidney leucocytes from three of five individuals, but in stimulated leucocytes from the other two individuals only 75% of the antiviral activity was neutralized. This shows that although IFNa1/IFNa2 are major IFNs secreted by poly I:C stimulated leucocytes, these cells can also produce additional molecules with IFN-like activity.