Induction and properties of guinea pig serum interferon. Preliminary report

Guinea pigs, 250-350 g body weight, both sexes, were injected with 5X10(8.5) EID50 NDV (Radom strain) intracardially and intraperitoneally simultaneously. The animals were bled by cardiac puncture 0, 3, 6, 12, 24 and 48 hours after injection. After virus inactivation, serum interferon titration was performed in cultures of guinea pig embryo kidney cells with 50 percent plaque inhibition test using VSV. The highest interferon titer (64 u./ml) was found after 6 hours of inductor injection. Interferon titer decreased quickly and after 12 hours it was lower than 16 u./ml. Guinea pig serum interferon induced by NDV was resistant to pH 2 and 56 degrees C during 1 hour. Interferon was inactivated by trypsin. The decribed interferon did not protect heterologous species cells (swine) against Teschen Disease Virus infection. Other properties of this interferon are being studied.