Polson and Turner investigated the pH stability and purification methods for lumpy skin disease (LSD) virus grown in chicken egg allantoic fluid. They demonstrated that LSD virus remains infectious across a wide pH range (2.0-10.0) under various time and temperature conditions, showing stability comparable to other known viruses. The researchers developed practical purification techniques based on virus adsorption properties. At pH 4.5, virus concentrated in protein precipitates formed by dialysis, with approximately 100-fold enrichment of virus in the precipitate compared to supernatant fluid over the pH range 3.2-4.4. Calcium phosphate also effectively adsorbed the virus. Further purification attempts using tryptic digestion and chloroform extraction achieved approximately 400-fold concentration with 40% virus recovery, though aggressive chemical extraction reduced infectivity. The authors concluded that the virus acts as an adsorbent on bulk protein precipitates rather than being selectively precipitated, providing useful concentration methods for future LSD virus studies.

Key findings

• Lumpy skin disease virus is stable across pH 2.0-10.0 at various temperatures and durations, with rapid inactivation only at extreme pH values (1.0 and 11.8)
• Virus concentrates in protein precipitates formed at pH 4.5 during dialysis, achieving 100-fold enrichment relative to supernatant fluid
• Calcium phosphate effectively adsorbs LSD virus and can be used for virus concentration
• Tryptic digestion of virus-protein precipitates achieved approximately 400-fold concentration with 40% recovery of infectious virus
• The virus likely adsorbs nonspecifically to protein precipitates rather than being selectively precipitated based on unique properties