Silva S V, Little P B
Department of Pathology, Ontario Veterinary College, University of Guelph.
Can J Vet Res. 1990 Jun;54(3):326-30.
A semi-purified outer membrane anionic antigen (AA) fraction was isolated from Haemophilus somnus by a modified procedure of anion exchange chromatography to yield a protein fraction free of lipopolysaccharides (LPS). The AA fraction (1 mg) was administered with or without the homologous lipopolysaccharide (10 micrograms/kg body weight) as vaccines to groups of cattle twice, three weeks apart. A control group which did not receive any antigen was included in the trial. Six weeks after the first vaccination, the animals were challenged intratracheally with a virulent pneumonic strain of H. somnus (70986) and observed for clinical signs of respiratory disease. The cattle were euthanized six days later and the lungs were evaluated for the severity of lesions macroscopically as well as histopathologically. Vaccination with AA alone provided the best protection against pneumonia as indicated by significantly lower clinical scores, less extensive gross lung lesions and mild histopathological lesions with immune cell infiltration. However, when AA was combined with LPS in the vaccination, this protective effect was negated and the animals showed more detrimental histopathological lesions than the controls.
通过改良的阴离子交换色谱法从睡眠嗜血杆菌中分离出一种半纯化的外膜阴离子抗原（AA）组分，以获得不含脂多糖（LPS）的蛋白质组分。将AA组分（1毫克）与同源脂多糖（10微克/千克体重）一起或不与同源脂多糖一起作为疫苗给牛群接种两次，间隔三周。试验中包括一个未接受任何抗原的对照组。首次接种疫苗六周后，给动物气管内接种一株强毒的睡眠嗜血杆菌肺炎菌株（70986），并观察呼吸道疾病的临床症状。六天后对牛实施安乐死，并从宏观和组织病理学方面评估肺部病变的严重程度。单独用AA疫苗接种提供了最佳的肺炎防护效果，表现为临床评分显著降低、肺部大体病变范围较小以及伴有免疫细胞浸润的轻度组织病理学病变。然而，当在疫苗接种中AA与LPS联合使用时，这种保护作用被抵消，并且动物表现出比对照组更严重的组织病理学病变。
