Furesz S E, Mallard B A, Bossé J T, Rosendal S, Wilkie B N, MacInnes J I
Department of Pathobiology, Ontario Veterinary College, University of Guelph, Canada.
Infect Immun. 1997 Feb;65(2):358-65. doi: 10.1128/iai.65.2.358-365.1997.
Current porcine pleuropneumonia bacterins afford only partial protection by decreasing mortality but not morbidity. In order to better understand the type(s) of immune response associated with protection, antibody- and cell-mediated immune responses (CMIR) were compared for piglets before and after administration of a commercial bacterin, which confers partial protection, or a low-dose (10(5) CFU/ml) aerosol challenge with Actinobacillus pleuropneumoniae CM5 (LD), which induces complete protection. Control groups received phosphate-buffered saline or adjuvant. Serum antibody response, antibody avidity, delayed-type hypersensitivity (DTH), and lymphocyte blastogenic responses were measured and compared among treatment groups to the lipopolysaccharide (LPS), capsular polysaccharide (CPS), hemolysin (HLY), and outer membrane proteins (OMP) of A. pleuropneumoniae. Peripheral blood lymphocytes and sera were collected prior to and following primary and secondary immunization-infection and high-dose A. pleuropneumoniae CM5 (10(7) CFU/ml) aerosol challenge. Serum antibody and DTH, particularly that to HLY, differed significantly between treatment groups, and increases were associated with protection. LD-infected piglets had higher antibody responses (P < or = 0.01) and antibody avidity (P < or = 0.10) than bacterin-vaccinated and control groups. Anti-HLY antibodies were consistently associated with protection, whereas anti-LPS and anti-CPS antibodies were not. LD-infected animals had higher DTH responses, particularly to HLY, than bacterin-vaccinated pigs (P < or = 0.03). The LD-infected group maintained consistent blastogenic responses to HLY, LPS, CPS, and OMP over the course of infection, unlike the bacterin-vaccinated and control animals. These data suggest that the immune responses induced by a commercial bacterin are very different from those induced by LD aerosol infection and that current bacterins may be modified, for instance, by addition of HLY, so as to stimulate responses which better reflect those induced by LD infection.
目前的猪胸膜肺炎疫苗仅通过降低死亡率而非发病率来提供部分保护。为了更好地了解与保护相关的免疫反应类型，在给仔猪接种可提供部分保护的商业疫苗后，或用胸膜肺炎放线杆菌CM5（低剂量，10⁵CFU/ml）进行气溶胶攻击（可诱导完全保护）之前和之后，对其抗体介导的免疫反应和细胞介导的免疫反应（CMIR）进行了比较。对照组接受磷酸盐缓冲盐水或佐剂。在各治疗组中，测定并比较了针对胸膜肺炎放线杆菌的脂多糖（LPS）、荚膜多糖（CPS）、溶血素（HLY）和外膜蛋白（OMP）的血清抗体反应、抗体亲和力、迟发型超敏反应（DTH）和淋巴细胞增殖反应。在初次和二次免疫感染以及高剂量胸膜肺炎放线杆菌CM5（10⁷CFU/ml）气溶胶攻击之前和之后，收集外周血淋巴细胞和血清。治疗组之间血清抗体和DTH存在显著差异，尤其是对HLY的差异，且增加与保护相关。与接种疫苗和对照组相比，感染低剂量的仔猪具有更高的抗体反应（P≤0.01）和抗体亲和力（P≤0.10）。抗HLY抗体始终与保护相关，而抗LPS和抗CPS抗体则不然。与接种疫苗的猪相比，感染低剂量的动物具有更高的DTH反应，尤其是对HLY的反应（P≤0.03）。与接种疫苗和对照动物不同，感染低剂量的组在感染过程中对HLY、LPS、CPS和OMP保持一致的增殖反应。这些数据表明，商业疫苗诱导的免疫反应与低剂量气溶胶感染诱导的免疫反应非常不同，并且目前的疫苗可能需要改进，例如通过添加HLY，以刺激更能反映低剂量感染诱导的反应。
