Fedorka-Cray P J, Stine D L, Greenwald J M, Gray J T, Huether M J, Anderson G A
Department of Veterinary Science, IANR, University of Nebraska, Lincoln.
Vet Microbiol. 1993 Oct;37(1-2):85-100. doi: 10.1016/0378-1135(93)90184-9.
Current bacterins provide only partial protection against morbidity and mortality in swine following infection by Actinobacillus pleuropneumoniae. We compared the efficacy of a cell-free concentrate from mid-log phase growth cultures of Actinobacillus pleuropneumoniae (APP) serotype 1 to four commercial bacterins. This cell-free preparation contained carbohydrate, endotoxin, and protein, and had hemolytic and cytotoxic activity. Sodium dodecyl-sulfate polyacrylamide gel electrophoresis analysis indicated the presence of one major 110,000-molecular-weight protein. This protein band also stained by the periodic acid Schiff method, indicating the presence of carbohydrate. Cell-free concentrates of APP serotypes 5 and 7 had identical profiles following electrophoresis and staining with either Coomassie blue for protein or Schiff reagent for carbohydrate. Lipopolysaccharide profiles for the cell-free concentrates of serotypes 1 and 5 were semi-rough while the LPS profile for serotype 7 was smooth. Five A. pleuropneumoniae-free SPF pigs per group were vaccinated on days 0 and 21 with cell-free concentrate of serotype 1 plus adjuvant, or one of four commercial bacterins according to the manufacturer's directions. Control pigs were vaccinated with PBS mixed with adjuvant. All pigs were challenged intranasally on day 35 with serotype 1 and necropsied on day 50. Protection was greatest in the cell-free concentrate group, as compared with all other groups, in that no deaths occurred, clinical scores were less severe, and percent lung affected was significantly reduced (P < 0.05). In addition, whole-cell ELISA titers were significantly increased (P < 0.05) postvaccination in the cell-free concentrate group, and postvaccination and postchallenge sera neutralized the hemolytic activity of the cell-free concentrate from serotypes 1 and 5 (P < 0.05), as compared with all other groups. No serum neutralization to the hemolysin of serotype 7 was observed. Immunoblot analysis using antisera derived from gnotobiotic pigs indicated that the cell-free vaccine generated a response that was identical to the response observed following live challenge. Similar, but not identical, responses were observed when antisera generated against the bacterins was used. This study indicates that an acellular vaccine containing multiple virulence factors can provide complete protection from mortality and significantly reduced morbidity to homologous challenge.
目前的疫苗仅能为感染胸膜肺炎放线杆菌的猪提供部分保护，降低发病率和死亡率。我们比较了1型胸膜肺炎放线杆菌（APP）对数中期生长培养物的无细胞浓缩物与四种商业疫苗的效力。这种无细胞制剂含有碳水化合物、内毒素和蛋白质，并具有溶血和细胞毒性活性。十二烷基硫酸钠聚丙烯酰胺凝胶电泳分析表明存在一种主要的分子量为110,000的蛋白质。这条蛋白带也能用过碘酸希夫氏法染色，表明存在碳水化合物。5型和7型APP的无细胞浓缩物在电泳以及用考马斯亮蓝染蛋白质或用希夫试剂染碳水化合物后具有相同的图谱。1型和5型无细胞浓缩物的脂多糖图谱为半粗糙型，而7型的脂多糖图谱为光滑型。每组五只无APP的SPF猪在第0天和第21天按照制造商的说明用1型无细胞浓缩物加佐剂或四种商业疫苗之一进行接种。对照猪用与佐剂混合的PBS进行接种。所有猪在第35天经鼻用1型菌进行攻毒，并在第50天进行剖检。与所有其他组相比，无细胞浓缩物组的保护效果最佳，该组没有死亡发生，临床评分较轻，肺脏受影响百分比显著降低（P<0.05）。此外，无细胞浓缩物组接种疫苗后全细胞ELISA滴度显著升高（P<0.05），与所有其他组相比，接种疫苗后和攻毒后的血清中和了1型和5型无细胞浓缩物的溶血活性（P<0.05）。未观察到对7型溶血素的血清中和作用。使用来自无菌猪的抗血清进行免疫印迹分析表明，无细胞疫苗产生的反应与活攻毒后观察到的反应相同。当使用针对商业疫苗产生抗体的抗血清时，观察到了相似但不完全相同的反应。这项研究表明，一种含有多种毒力因子的无细胞疫苗可以提供完全的死亡保护，并显著降低同源攻毒的发病率。
