Inactivation of interferon by serum and synovial fluids

The stability of interferons-alpha, -beta, and -gamma (IFN) in serum and synovial fluids were compared. Interferon-beta was the least stable interferon species, losing at least 75% of its activity during incubation in samples of both serum and synovial fluid. Interferon-alpha was the most stable IFN, but interferon-gamma under these conditions approached the stability of the alpha species. The inactivation of IFN-beta was found due to dialyzable factors and hence not classical antibodies.