Kidane A, Guimond P, Ju T R, Sanchez M, Gibson J, Bowersock T L
Pharmacia & Upjohn, Animal Health, Kalamazoo, MI 49001-0199, USA.
Vaccine. 2001 Mar 21;19(17-19):2637-46. doi: 10.1016/s0264-410x(00)00494-1.
The goal of this study was to examine the efficacy of oral delivery of alginate encapsulated outer membrane proteins (OMP) of Pasteurella haemolytica and a commercial One-Shot vaccine in inducing protection in mice against lethal challenge with virulent P. haemolytica. We examined two alginate microsphere formulations and compared them with oral unencapsulated and subcutaneously administered vaccines. Alginate microspheres were made by the emulsion-cross-linking technique. They were examined for size, hydrophobicity, and antigen loading efficiency before they were used in the study. Mice were vaccinated by administering 200 microg of antigens in 200 microl of microspheres suspension orally or subcutaneously. One group of mice received blank microspheres and a second group was given unencapsulated antigen orally. A third and a fourth group received different formulations of alginate encapsulated antigens by oral administration. Three groups received subcutaneous inoculations (alginate encapsulated, non-adjuvanted and unencapsulated antigens, and adjuvanted One-Shot), and one group received water (naïve group). Mice were vaccinated orally for four consecutive days and challenged with P. haemolytica 5 weeks after the first vaccination. Weekly serum and feces samples were assayed for antigen specific antibodies. The number of dead mice in each group 4 days post challenge was used to compare the efficacy of the various vaccination groups. The mean volume sizes of blank alginate microsphere formulations A, and AA were 15.9, 16 and 9.2 microm, respectively. Hydrophobicity of the microspheres was evaluated by measuring contact angle on a glass slide coated with the microspheres. The contact angles on A and AA were 37.8 and 74.3 degrees, respectively. Antigen concentration in a 1:1 w/w suspension of microspheres in water was 0.9 mg/ml. Rate of death for the blank group was 42.8% whereas for groups vaccinated with antigens encapsulated in A and AA the death rates were 40 and 33.33%, respectively. The death rate in mice vaccinated with unencapsulated antigens was 55.6%. Groups vaccinated by subcutaneous inoculation showed the lowest death rate. These results show that encapsulating OMP and One-Shot in alginate microspheres improves their performance as an oral vaccine.
本研究的目的是检验口服海藻酸盐包封的溶血巴斯德菌外膜蛋白（OMP）和一种市售的一次性疫苗在诱导小鼠抵抗强毒溶血巴斯德菌致死性攻击方面的效果。我们研究了两种海藻酸盐微球制剂，并将它们与口服未包封疫苗及皮下注射疫苗进行比较。海藻酸盐微球采用乳化交联技术制备。在用于研究之前，对其大小、疏水性和抗原负载效率进行了检测。通过口服或皮下给予小鼠200微升微球悬液中的200微克抗原进行疫苗接种。一组小鼠接受空白微球，另一组口服未包封的抗原。第三组和第四组通过口服给予不同制剂的海藻酸盐包封抗原。三组接受皮下接种（海藻酸盐包封、无佐剂和未包封抗原以及佐剂一次性疫苗），一组接受水（未免疫组）。小鼠连续4天口服接种疫苗，并在首次接种5周后用溶血巴斯德菌进行攻击。每周对血清和粪便样本检测抗原特异性抗体。攻击后4天每组死亡小鼠的数量用于比较不同疫苗接种组的效果。空白海藻酸盐微球制剂A和AA的平均体积大小分别为15.9、16和9.2微米。通过测量微球包被的载玻片上的接触角来评估微球的疏水性。A和AA上的接触角分别为37.8度和74.3度。微球在水中1:1 w/w悬液中的抗原浓度为0.9毫克/毫升。空白组的死亡率为42.8%，而接种A和AA包封抗原组的死亡率分别为40%和33.33%。接种未包封抗原的小鼠死亡率为55.6%。皮下接种疫苗的组死亡率最低。这些结果表明，将OMP和一次性疫苗包封在海藻酸盐微球中可提高其作为口服疫苗的性能。
