Suckow M A, Bowersock T L, Nielsen K, Grigdesby C F
Laboratory Animal Program, Purdue University, West Lafayette, USA.
Lab Anim. 1996 Apr;30(2):120-6. doi: 10.1258/002367796780865808.
Cholera toxin (CT) is a potent adjuvant for the mucosal immune system. The purpose of this study was to determine if coadministration of CT with a potassium thiocyanate extract of Pasteurella multocida (PTE) leads to enhanced anti-PTE antibody activity and increased protection of rabbits against infection with P. multocida and associated disease. Groups of rabbits were immunized intranasally on days 0, 7, and 14, with phosphate buffered saline (PBS), 200 micrograms of CT, 1.0 mg of PTE, or 1.0 mg PTE with 200 micrograms CT. Nasal lavage and serum samples were collected over 28 days after initial immunization and evaluated by ELISA for specific antibody directed against PTE. Marked increases in serum (IgG) and nasal lavage (IgA) anti-PTE antibody activity were found beginning after day 14 in rabbits immunized with PTE. Rabbits immunized with PTE and CT demonstrated further increases in this activity. Tracheobronchial lavage samples collected at the time of necropsy demonstrated a significant level of anti-PTE IgA activity in animals immunized with PTE, and coadministration with CT stimulated a further significant increase in this activity. Groups of similarly immunized rabbits were challenged 16 days after initial immunization with 5 x 10(7) CFUs of P. multocida. Nasal lavage samples were cultured for P. multocida over the next 10 days. Rabbits were euthanized within 10 days after challenge, tissues cultured for P. multocida, and histopathologic lesion severity graded using a numeric scale. Rabbits immunized with PTE survived longer, had less severe lesions of the lungs, pleura, and liver, and fewer P. multocida CFUs cultured from samples than PBS or CT controls. Coadministration of CT led to further reductions in lesion severity of those tissues and numbers of P. multocida CFUs cultured from samples. Increased nasal turbinate atrophy of rabbits immunized with PTE with or without CT was associated with increased mean survival time. In summary, coadministration of CT with PTE enhanced protective immunity to P. multocida disease and infection in rabbits.
霍乱毒素（CT）是一种对黏膜免疫系统有效的佐剂。本研究的目的是确定CT与多杀巴斯德菌硫氰酸钾提取物（PTE）联合使用是否能增强抗PTE抗体活性，并增强兔对多杀巴斯德菌感染及相关疾病的抵抗力。将兔分组，在第0、7和14天经鼻免疫，分别给予磷酸盐缓冲盐水（PBS）、200微克CT、1.0毫克PTE或1.0毫克PTE与200微克CT。在初次免疫后的28天内收集鼻腔灌洗液和血清样本，并用ELISA法检测针对PTE的特异性抗体。在用PTE免疫的兔中，在第14天后血清（IgG）和鼻腔灌洗液（IgA）抗PTE抗体活性显著增加。用PTE和CT免疫的兔该活性进一步增加。在尸检时收集的气管支气管灌洗液样本显示，用PTE免疫的动物中抗PTE IgA活性达到显著水平，与CT联合使用可进一步显著提高该活性。将相似免疫的兔组在初次免疫16天后用5×10⁷CFU的多杀巴斯德菌进行攻毒。在接下来的10天内对鼻腔灌洗液样本进行多杀巴斯德菌培养。在攻毒后10天内对兔实施安乐死，对组织进行多杀巴斯德菌培养，并使用数字评分法对组织病理学病变严重程度进行分级。用PTE免疫的兔存活时间更长，肺、胸膜和肝脏的病变较轻，样本中培养出的多杀巴斯德菌CFU比PBS或CT对照组少。CT联合使用导致这些组织的病变严重程度和样本中培养出的多杀巴斯德菌CFU数量进一步减少。无论有无CT，用PTE免疫的兔鼻甲骨萎缩增加与平均存活时间延长有关。总之，CT与PTE联合使用增强了兔对多杀巴斯德菌疾病和感染的保护性免疫。
