Wang Shiyan, Jiao Wenjie, Zhao Dannan, Gong Yuzhu, Ni Jingying, Wu Huawei, Du Jige, Wang Tuanjie, Yin Chunsheng
China Institute of Veterinary Drug Control, Beijing 100081, China.
College of Veterinary Medicine, Hunan Agricultural University, Changsha 410128, China.
Vaccines (Basel). 2025 Jul 16;13(7):758. doi: 10.3390/vaccines13070758.
Canine parvovirus (CPV) is a highly pathogenic virus that predominantly affects puppies, with mortality rates exceeding 70%. Although commercial multivalent live attenuated vaccines (MLV) are widely employed, their efficacy is often compromised by maternal antibody interference. Consequently, the development of novel vaccines remains imperative for effective CPV control. Recombinant CPV VP2 protein (rVP2) and canine interlukine 12 protein (rcIL-12) were expressed using the Bac-to-Bac baculovirus expression system and the biological activity of these proteins was assessed through hemagglutination, Cell Counting Kit-8 (CCK8) and IFN-γ induction assays. The combined immunoenhancement effect of rVP2 and rcIL-12 protein was evaluated in puppies. Both rVP2 and rcIL-12 were successfully expressed and purified, exhibiting confirmed antigenicity, immunogenicity, and bioactivity. Co-administration of rVP2 with rcIL-12 elicited higher neutralizing antibody titer (6-7 times higher), complete challenge protection efficiency (no clinical symptoms and tissue and organ lesions), fewer viral shedding (decreasing significantly 8-day post challenge) and superior viral blockade (lower viral load in the organism) compared to rVP2 alone. Our findings demonstrate that rVP2 co-administered with rcIL-12 induces robust protective immunity in puppies and significantly mitigated the inhibitory effects of maternal antibodies. This represents a promising strategy for enabling earlier vaccination in puppies and rational design of CPV subunit vaccines.
犬细小病毒（CPV）是一种高致病性病毒，主要感染幼犬，死亡率超过70%。尽管商业多价减毒活疫苗（MLV）被广泛使用，但其效力常受母源抗体干扰的影响。因此，开发新型疫苗对于有效控制CPV仍然至关重要。使用杆状病毒表达系统表达重组CPV VP2蛋白（rVP2）和犬白细胞介素12蛋白（rcIL-12），并通过血凝试验、细胞计数试剂盒-8（CCK8）和IFN-γ诱导试验评估这些蛋白的生物活性。在幼犬中评估rVP2和rcIL-12蛋白的联合免疫增强效果。rVP2和rcIL-12均成功表达并纯化，表现出确定的抗原性、免疫原性和生物活性。与单独使用rVP2相比，rVP2与rcIL-12联合给药可诱导更高的中和抗体滴度（高6 - 7倍）、完全的攻毒保护效率（无临床症状以及组织和器官病变）、更少的病毒排出（攻毒后8天显著减少）以及更好的病毒阻断效果（机体中的病毒载量更低）。我们的研究结果表明，rVP2与rcIL-12联合给药可在幼犬中诱导强大防御性免疫，并显著减轻母源抗体的抑制作用。这代表了一种有前景的策略，可实现幼犬更早接种疫苗并合理设计CPV亚单位疫苗。
