Rajeev S, Kania S A, Nair R V, McPherson J T, Moore R N, Bemis D A
Department of Comparative Medicine, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA.
Vaccine. 2001 Sep 14;19(32):4842-50. doi: 10.1016/s0264-410x(01)00226-2.
Leukotoxin produced by Mannheimia (Pasteurella) haemolytica is an important virulence factor in shipping fever pneumonia in feedlot cattle and is a critical protective antigen. In this study, the immune response to a chimeric protein generated by combining a gene fragment encoding neutralizing epitopes of M. haemolytica leukotoxin and a fimbrial protein gene (fim N) from Bordetella bronchiseptica was evaluated. The recombinant gene was cloned in a bacterial expression vector under the control of the tac promoter and expressed as a fusion protein with glutathione-S-transferase (GST) in Escherichia coli. Immunization of mice with the recombinant protein, GST-LTXFIM elicited a significantly stronger anti-leukotoxin antibody response than comparable immunizations with GST-LTX fusion proteins lacking FIM N. The GST-LTXFIM was also more stable than GST-LTX during storage at -80 degrees C, thus alleviating a stability problem inherent to leukotoxin. This chimeric protein may be a candidate for inclusion in new generation vaccines against shipping fever pneumonia.
溶血曼氏杆菌（巴斯德氏菌）产生的白细胞毒素是育肥牛运输热肺炎中的一种重要毒力因子，也是一种关键的保护性抗原。在本研究中，评估了对通过将编码溶血曼氏杆菌白细胞毒素中和表位的基因片段与支气管败血波氏杆菌的菌毛蛋白基因（fim N）相结合而产生的嵌合蛋白的免疫反应。重组基因在tac启动子控制下克隆到细菌表达载体中，并在大肠杆菌中作为与谷胱甘肽-S-转移酶（GST）的融合蛋白表达。用重组蛋白GST-LTXFIM免疫小鼠，比用缺乏fim N的GST-LTX融合蛋白进行的类似免疫引发了明显更强的抗白细胞毒素抗体反应。在-80℃储存期间，GST-LTXFIM也比GST-LTX更稳定，从而缓解了白细胞毒素固有的稳定性问题。这种嵌合蛋白可能是新一代抗运输热肺炎疫苗的候选成分。
