Process development for the mass production of Ehrlichia ruminantium

Area of Science:

• Veterinary Microbiology
• Bioprocess Engineering
• Vaccine Development

Background:

• Heartwater disease, caused by Ehrlichia ruminantium (ER), poses a significant threat to ruminant health.
• Current production methods for ER are not optimized for large-scale, cost-effective vaccine manufacturing.

Purpose of the Study:

• To optimize a cost-effective stirred tank bioreactor process for the mass production of Ehrlichia ruminantium (ER).
• To validate the scalability and economic viability of this process for heartwater vaccine production.

Main Methods:

• Optimization of ruminant endothelial cell culture conditions in stirred tanks, including inoculum size, microcarrier type, serum concentration, and agitation rate.
• Scale-up strategies for cell inoculum were tested.
• Validation of ER production using two ER strains (Gardel and Welgevonden) under optimized conditions, analyzing infection parameters and medium strategies.
• Process suitability was assessed up to a 2-liter scale.

Main Results:

• Successfully optimized cell growth parameters for mass production of ruminant endothelial cells in stirred tanks.
• Achieved a 6.5-fold increase in ER production yields under serum-free conditions in stirred tank bioreactors.
• Demonstrated process suitability up to a 2-liter scale.
• Preliminary cost analysis indicated stirred tanks as the most economical culture method.

Conclusions:

• Stirred tank bioreactors provide a scalable and controlled method for producing Ehrlichia ruminantium (ER).
• The optimized process significantly enhances ER production yields, crucial for developing effective heartwater vaccines.
• This advancement offers new possibilities for producing vaccines against other Ehrlichia species impacting human and animal health.