STUDIES IN RODENT POLIOMYELITIS : II. CULTIVATION OF THE MURINE STRAIN OF SK POLIOMYELITIS VIRUS

Area of Science:

• Virology
• Microbiology
• Cell Culture

Background:

• Murine viruses present challenges for in vitro cultivation.
• Understanding viral propagation and infectivity is crucial for developing antiviral strategies.

Purpose of the Study:

• To establish optimal conditions for in vitro growth of a murine virus.
• To characterize the physical and biological properties of the cultured murine virus.
• To investigate the potential of the cultured virus as an interfering agent.

Main Methods:

• Cultivation of murine virus in embryonic mouse brain-serum ultrafiltrate.
• Optimization of culture pH for maximum virus potency.
• Determination of virus propagation rates and infectivity through mouse inoculation.
• Filtration studies to estimate particle size.
• Cross-infection experiments and interference assays with poliomyelitis virus.

Main Results:

• Murine virus successfully cultured in vitro, failing to grow in chick tissues or eggs.
• Optimal virus titers achieved at pH 7.3-7.6.
• Rapid virus propagation observed, with peak titers at 19 hours (large inoculum) and 72 hours (small inoculum).
• Cultured virus maintained infectivity via intracerebral injection but lost it via peripheral routes after subcultivation.
• Particle size estimated between 10-15 mmicro.
• Murine culture virus demonstrated distinctness from lymphocytic choriomeningitis virus.
• Interference with poliomyelitis virus in monkeys was observed, effective against smaller doses.

Conclusions:

• The murine virus can be effectively cultured in vitro under specific conditions.
• The cultured virus exhibits distinct characteristics and maintains infectivity through intracerebral routes.
• Murine culture virus shows potential as an interfering agent against other viral infections, notably poliomyelitis.