[Experimental study of apoptosis induced by infectious bursal disease virus, using tunel assay]

The purpose of the present in vivo study was to evaluate correlation of the virulence of the infectious bursal disease virus with the rate of apoptotic changes of the immature B lymphocytes in Bursa Fabricius [BF] and lymphoid cells of spleen. Experimental study. 21-day-old SPF chicks of leghorn breed.90 chicks were divided into three groups [TEST-IBDV, TEST -VAC and Control] of30 chicks each. Inoculation of the TEST-IBDV, TEST -VAC and Control groups were done with 1R-499 serotype of high-virulence infectious bursal disease Virus [WIBDV], D78 intermediate vaccine and normal saline, respectively. Furthermore, 20 chicks were categorited into two groups [Test and Control] of 10 chicks each. Test and Control groups were inoculated with WIBDV and normal saline, respectively. 3 days after inoculation, samples of BF and splenic tissues were sent to Pathology Lab for LM, H and Esatinig and TUNEL studies. Kruskal-Wallis, ANOVA and Mann-Whimeytest.LM and H and E staining showed many significant differences among groups. Furthermore, we showed VP2 and VP5, INF-gamma and TNF-alpha were the major inductive factors for development of apoptosis in the immature B lymphocytes of BF and spleen.The present in vivo research showed that there is always a significant correlation between the virulence of the virus and the rate of apoptotic changes in the BF tissue. Moreover, apoptosis can be considered as a definite factor in the pathogenesisof infectious bursaldisease [IBD]