鸡传染性法氏囊病超强毒感染后SPF鸡免疫器官病理学观察

Pathological Observation on Immune Organs of Special-Pathogen-Free(SPF) Chicks Inoculated with Very Virulent Infectious Bursal Disease Virus

IBDV超强毒株LX株接种 2周龄SPF雏鸡后 ,其致病性不同于经典强毒株CJ80 1株 ,它主要引起接种鸡全身性炎症反应 ,法氏囊、脾脏、盲肠扁桃体等免疫器官中大量异嗜性白细胞、巨噬细胞浸润 ,淋巴细胞严重坏死崩解 ,胸腺皮质严重萎缩、坏死 ,骨髓中造血细胞减少、巨噬细胞和脂肪细胞增生。在接种后 14d法氏囊淋巴滤泡严重萎缩、淋巴细胞排空形成囊腺样结构 ,未见恢复正常 ,其它免疫器官形态基本恢复正常。电镜观察 ,接种后 2和4d可见胸腺淋巴细胞胞浆浓集、染色质周边化形成新月形 ,表现细胞凋亡特征 ;在法氏囊坏死淋巴细胞胞浆中可见6 0nm大小呈晶格排列或散在的病毒粒子。研究初步探明了鸡传染性法氏囊病病毒超强毒的致病机理。

2-week-old SPF chicks inoculated with very virulent infectious bursal disease virus(vvIBDV)strain LX was characterized by general inflammatory response,resulting in infiltration in large quantities of heterophils and macrophages into the bursa,spleen,and cecal tonsil with severe necrosis and depletion of lymphocytes,severe atrophy of the thymic cortex with necrosis of thymocytes,and infiltration of macrophages and adipose cells into bone marrow accompanied by marked decrease in matopoietic cells,which was different from those of the chicks inoculated with classical virulent IBDV strain CJ801.Chicks with the strain LX developed severe atrophy,bursal lymphoid follicles were replaced by proliferated reticular cells on the fourteenth day after inoculation,whereas other lymphoid tissues including the spleen,thymus,cecal tonsils,bone marrow,and Harderian gland returned to normal at 14 days post-inoculation.By using electron microscope technique,apoptosis characterized by condensed cytoplasm and crescent-shaped chromatin abutting the nuclear membrane was observed in lymphocytes in the thymus,and crystalline-arrayed or scattered viral particles with the size of 60nm were observed in the cytoplasm of necrotic bursal follicles on the second and fourth day post-inoculation with the strain LX.It showed that the pathogenesis of vvIBDV to SPF chicks had been preliminarily discerned from this report.