EFFECTIVENESS OF CRYOPRESERVED CHICKEN EMBRYOFIBROBLAST CELLS FOR PROPAGATION OF DUCK ENTERITISVIRUS AND FOWLPOX VIRUSHIRAMONI SARMAH, SAMSUN NEHER, SOPHIA M. GOGOI, NAYANMONIKONWAR, KEVISENUO EVALYN VIZO, PRANITA SHERPA, HIMASRI DAS, KANYAGA PARAMESHWARIM., N.N BARMAN AND D.P BORAAbstract Primary chicken embryo fibroblast (CEF) cultures are excellent model systems for in-vitro viruspropagation. However, the cumbersome preparation process of CEF makes cryopreservation highlyessential. Cryopreservation in Liquid Nitrogen liquid phase (-196 °C) or vapour phase (-156 °C) arefrequently used methods. In the present study, efficiency of cryopreserved primary CEF cells for thepropagation of Duck plague virus and Fowl pox virus was evaluated. The cells were preserved for differenttime periods and different cooling methodologies were employed in order to assess the effects exerted bythese variations. The efficiency of the cells was compared based on cell viability/ revival rate, ability to formmonolayer and TCID50 of the propagated viruses. Cell count revealed viability of 75.60% and 68% post 2weeks and 6 months of cryopreservation respectively following step freezing method. On the other hand,cells preserved using insulated cryo-containers exhibited 89% and 80% viability post 2 weeks and 6 monthsof cryopreservation respectively. Development of complete monolayer could be seen within 24 hours in allthe batches irrespective of the cooling method used and the cryopreservation storage time. Infection withDPV and FPV yielded respective cytopathic effect from 48 hours onwards. CPE observed in the freshlyprepared CEF and in those revived 2 weeks and 6 months post freezing, were similar in terms of typicalcharacteristics and duration of appearance. From the findings of the present study it is evident thatcryopreservation of CEF cells is a convenient and practical approach for virus propagation.Cryopreservation of primary cells offers a definite advantage over repeated culture preparation which islabour intensive, time consuming and dependent on the availability of embryonated eggs. |