Inactivation of viruses in labile blood derivatives. II. Physical methods

Area of Science:

• Biochemistry
• Virology
• Biotechnology

Background:

• Blood derivatives, such as anti-hemophilic factor (AHF) concentrates, are crucial for treating bleeding disorders.
• Ensuring the viral safety of these labile blood products is paramount to patient health.
• Viruses pose a significant risk to recipients of blood-derived therapies.

Purpose of the Study:

• To evaluate the thermal inactivation of viruses in anti-hemophilic factor (AHF) concentrates.
• To determine the impact of additives and different physical states (liquid vs. lyophilized) on virus inactivation and protein activity.
• To assess the efficacy of gamma irradiation as a viral inactivation method for AHF concentrates.

Main Methods:

• Marker viruses (VSV, Sindbis, Sendai, EMC) were added to AHF concentrates.
• Thermal inactivation studies were conducted at 60, 70, and 80 degrees C, with and without additives (glycine, sucrose, potassium citrate).
• Lyophilized AHF was subjected to heat and gamma irradiation (cobalt 60 source).
• Virus inactivation was quantified by infectious units, and AHF activity was measured.
• Protein changes were analyzed using electrophoresis.

Main Results:

• Additives like glycine and sucrose, or potassium citrate, reduced the rate of virus inactivation at 60°C but allowed significant viral clearance (at least 10^4 infectious units) within 10 hours.
• Temperatures above 60°C (70-80°C) caused substantial loss (≥90%) of AHF activity.
• Heating lyophilized AHF at 60°C for up to 72 hours did not reduce AHF activity, though some protein alterations were observed.
• Gamma irradiation of lyophilized AHF at 1 megarad inactivated VSV (≥6.0 logs) and Sindbis virus (3.3 logs) while maintaining acceptable AHF yield.
• Higher irradiation doses (2 megarads) resulted in unacceptable AHF yield.

Conclusions:

• Thermal inactivation is effective for viral clearance in AHF concentrates, but careful temperature control is needed to preserve protein activity.
• Lyophilization offers protection against thermal damage to AHF during viral inactivation.
• Gamma irradiation at 1 megarad is a viable method for viral inactivation in lyophilized AHF concentrates, balancing safety and efficacy.