Abstract
Infectious bronchitis virus is an acute contagious disease cause severe economic losses in poultry production worldwide. Virus isolation is the golden standard for IBV diagnosis so the aim of this study was comparing the different biological systems for isolation of infectious bronchitis virus. The Egyptian varian2 IBV strain representative to the current circulating strain in Egypt was isolated in SPF-ECE, chicken embryo kidney cell (CEK) and in vero cell line and was confirmed for IBV detection by Reverse transcriptase Real time PCR (RRT-PCR) using IB specific primers. Comparison of different isolation methods was done by generating a standard curve by real time PCR. The results revealed that The propagated virus in CEK showed the highest virus titer (5.952 x 106 and 3.245 x 106) than vero cell line (7.184 x 101 and 2.14 x 103) and ECE (7.536 x 103 and 5.444 x 105) after both 48 and 72 hours respectively.

Key words: Infectious bronchitis virus, Chicken Embryo Kidney (CEK), Vero cell, isolation, standard curve, Embryonated Chicken Egg (ECE)