Leptospirosis is a debilitating infectious disease that detrimentally affects both animals and humans; therefore, disease prevention has become a high priority to avoid high incidence rates of disease in the herd and break the transmission cycle to humans. Thus, there remains an important unmet need for a prophylactic vaccine that can provide long-term immunity against leptospirosis in cattle. Herein, a novel vaccine formulation was developed where poly(diaminosulfide) polymer was employed to fabricate microparticles encapsulating the antigen of Leptospira borgpetersenii serovar Hardjo strain HB15B203 (L203-PNSN). A prime-boost vaccination with a L203-PNSN microparticle formulation increased the population of L203-specific CD3+ T cells and CD21+ B cells to levels that were significantly higher than those of cattle vaccinated with L203-AlOH or the vehicle control (empty PNSN microparticles and blank AlOH). In addition, L203-PNSN was demonstrated to stimulate durable humoral immune responses as evidenced by the increases in the antibody serum titers following the vaccination. It was also found that cattle vaccinated with L203-PNSN produced higher macroscopic agglutinating titers than cattle in other groups. Thus, it can be concluded that L203-PNSN is a novel first-in-class microparticle-based Leptospira vaccine that represents a powerful platform with the potential to serve as a prophylactic vaccine against leptospiral infection in cattle.

中文翻译：

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用于递送钩端螺旋体抗原的基于聚（二氨基硫化物）微粒的疫苗。

钩端螺旋体病是一种使人衰弱的传染病，对动物和人类都有不利影响；因此，疾病预防已成为避免畜群疾病高发病率和打破向人类传播的循环的重中之重。因此，对于可以在牛中提供针对钩端螺旋体病的长期免疫力的预防性疫苗仍然存在重要的未满足需求。在此，开发了一种新型疫苗制剂，其中使用聚（二氨基硫化物）聚合物来制造包封博氏钩端螺旋体 Hardjo 菌株 HB15B203 (L203-PNSN) 抗原的微粒。使用 L203-PNSN 微粒制剂的初免加强疫苗接种将 L203 特异性 CD3+ T 细胞和 CD21+ B 细胞的数量增加到显着高于接种 L203-AlOH 的牛或载体对照（空的 PNSN 微粒和空白 AlOH)。此外，L203-PNSN 被证明可刺激持久的体液免疫反应，疫苗接种后抗体血清滴度的增加就证明了这一点。还发现接种 L203-PNSN 的牛比其他组的牛产生更高的肉眼凝集效价。因此，可以得出结论，L203-PNSN 是一种新型的一流的基于微粒的钩端螺旋体疫苗，它代表了一个强大的平台，有可能用作牛的钩端螺旋体感染的预防性疫苗。