THE CULTIVATION OF THE GRANULES OF VACCINIA VIRUS

Area of Science:

• Virology
• Cell Biology
• Immunology

Background:

• Glycerolated vaccinia calf lymph is a source of vaccine virus.
• Understanding the viability and potency of vaccinia virus components is crucial for vaccine development and efficacy.
• Previous studies have focused on whole virus preparations, leaving the properties of isolated components less explored.

Purpose of the Study:

• To describe a technique for isolating and cultivating vaccinia "granules" in vitro.
• To determine the viability and characteristics of these isolated granules.
• To assess the potency of vaccinia granules compared to the remaining lymph fluid.

Main Methods:

• Separation of vaccinia "granules" from glycerolated vaccinia calf lymph.
• In vitro cultivation of isolated granules with embryonic tissues.
• Viability testing using rabbit corneal inoculation.
• Potency assessment based on cultivation with living versus dying cells.

Main Results:

• Isolated vaccinia granules remained viable for up to 71 days when cultured with embryonic tissues.
• Granule viability was dependent on the host cells; they remained potent with living cells but not dying cells.
• The potency of vaccinia granules increased with the age of the in vitro culture.
• The fluid portion of the vaccinia lymph, after granule removal, was found to be consistently impotent.

Conclusions:

• Vaccinia "granules" represent a viable and potent component of vaccinia calf lymph.
• The in vitro culture system effectively maintains the viability and characteristics of vaccinia granules.
• These findings highlight the importance of the "granule" fraction for vaccinia virus infectivity and potential vaccine applications.