Unidad de Biología Parasitaria, Departamento de Biología Celular y Molecular, Facultad de Ciencias, Instituto de Higiene, UdelaR. Av. A. Navarro 3051, CP11600 Montevideo, Uruguay.
Vaccine. 2011 Nov 8;29(48):9057-63. doi: 10.1016/j.vaccine.2011.09.020. Epub 2011 Sep 20.
Fasciola hepatica M17 leucine aminopeptidase (FhLAP) is thought to play a role in catabolizing peptides generated by the concerted activity of gut-associated endopeptidases on host polypeptides, thus releasing amino acids to be used in protein anabolism. In this study, a recombinant functional form of this homo hexameric metallopeptidase produced in Escherichia coli was used in combination with adjuvants of different types in a vaccination trial in Corriedale sheep against experimental challenge with F. hepatica metacercariae. The experimental assay consisted of 6 groups of 10 animals; 5 of the groups (1-5) were subcutaneously inoculated at weeks 0 and 4 with 100 μg of rFhLAP mixed with Freund's complete plus incomplete adjuvant (group 1), Alum (group 2), Adyuvac 50 (group 3), DEAE-D (group 4) and Ribi (group 5); the adjuvant control group (group 6) received Freund's adjuvant. Two weeks after the booster, the sheep were orally challenged with 200 metacercariae. Immunization with rFhLAP induced significant reduction in fluke burdens in all vaccinated groups: 83.8% in the Freund's group, 86.7% in the Alum group, 74.4% in the Adyuvac 50 group, 49.8% in the Ribi group and 49.5% in the DEAE-D group compared to the adjuvant control group. Morphometric analysis of recovered liver flukes showed no significant size modifications in the different vaccination groups. All vaccine preparations elicited specific IgG, IgG1 and IgG2 responses. This study shows that a liver fluke vaccine based on rFhLAP combined with different adjuvants significantly reduced worm burden in a ruminant species that was high in animals that received the enzyme along with the commercially approved adjuvants Alum and Adyuvac 50.
肝片形吸虫 M17 亮氨酸氨肽酶（FhLAP）被认为在分解由肠道相关内肽酶协同作用于宿主多肽产生的肽中发挥作用，从而释放氨基酸用于蛋白质合成代谢。在这项研究中，使用重组的功能性同型六聚金属肽酶，该酶在大肠杆菌中产生，与不同类型的佐剂结合，在科里代尔羊中进行了针对肝片形吸虫囊蚴实验性挑战的疫苗接种试验。实验检测由 6 组每组 10 只动物组成；其中 5 组（1-5）在第 0 周和第 4 周通过皮下接种 100 μg 的 rFhLAP，与弗氏完全佐剂和不完全佐剂（第 1 组）、明矾（第 2 组）、Adyuvac 50（第 3 组）、DEAE-D（第 4 组）和 Ribi（第 5 组）混合；佐剂对照组（第 6 组）接受弗氏佐剂。加强针后两周，羊通过口服感染 200 个囊蚴。用 rFhLAP 免疫可显著降低所有接种组的吸虫负担：弗氏佐剂组 83.8%、明矾组 86.7%、Adyuvac 50 组 74.4%、Ribi 组 49.8%和 DEAE-D 组 49.5%与佐剂对照组相比。对回收的肝吸虫的形态计量学分析显示，不同疫苗接种组的大小没有明显改变。所有疫苗制剂都引起了特异性 IgG、IgG1 和 IgG2 反应。这项研究表明，基于 rFhLAP 的肝片形吸虫疫苗与不同佐剂联合使用，可显著降低在高动物中用该酶和商业批准的佐剂明矾和 Adyuvac 50 接种的反刍动物物种的蠕虫负担。
