The effect of cobra venom factor on alternative pathway hemolytic activity in mice.

The in vivo effect of cobra venom factor (CVF) on murine alternative complement pathway hemolytic activity was measured with a recently developed microassay. Four different dosage schedules of CVF were compared. Hemolytic titers were lowered to less than 5% of the baseline value by 6 hours after the first dose of CVF (62.5 - 200 U/kg), and remained low for 3-5 days, depending upon total dose, route and schedule of CVF administration. Titers at days 6-9 after initial CVF injection increased above baseline in animals given two doses of CVF separated by 48 hours.