Theileria annulata Schizont Infected Cell line Culture in Aerobic Bioreactor System.

The protozoan Theileria annulata is the causative agent of malignant bovine Theileriosis in Iran. The sporozoites of the parasite invade bovine MHC II cells, where they differentiate into schizonts, and stimulate the infected cells to unlimited cell divisions. The in vitro culture of infected bovine monocytes/macrophages has been used for production of live attenuated bovine Theileriosis for a long time in many involved countries including Iran. The method of vaccine production briefly is the culture of Theileria annulata infected bovine cell lines in tissue culture flasks. But the method has some disadvantages, high risk of contamination during cell passage and culture manipulating, needs to more space, incubator area, sterilization facility and necessity manipulation for culture, passages and cell harvesting. The efficacy of vaccine in preventing the disease and on the other hand, rare side effects of live attenuated vaccine in imported sensitive cattle lead to high demands for vaccine from national veterinary organization. This request for live vaccine needs producing the vaccine during all the year and preserving it in appropriate condition. However, cell culture in short period of time and high yield of production in each lot are the advantages of the new proposed methodology. In this study culture of Theileria annulata infected cell lines were carried out in simple tissue culture bottles and then in 10 liter automated aerobic bioreactor. Precise control of temperature (centigrade degree), aeration (soluble oxygen), agitation (round per minute), adding antifoam and daily sampling in sterile condition were some of the advantages of this new proposed and experimental method of tissue culture. The results of this research showed the schizont infected cell lines tolerate the new system even in agitating to 300 rpm very well. In addition, the effect of aeration, antifoam and the quantity of preliminary seeds per ml were evaluated. In conclusion, using the new system for propagation of T.annulata in infected cell lines makes high production to more than 200% increase and decreasing the risk factors in cell culture manipulating and we anticipate the success of this technique for developing the bovine Theileriosis vaccine by scaling up the production in aerobic bioreactors.