Pathogenic spirochetes from genus Leptospira are etiologic agents of leptospirosis. Cellular vaccines against Leptospira infection often elicit mainly response against the LPS antigen of the serovars present in the formulation. There is no suitable protein candidate capable of replacing whole-cell vaccines, thus requiring new approaches on vaccine development to improve leptospirosis prevention. Our goal was to develop a whole-cell vaccine sorovar-independent based on LPS removal and conservation of protein antigens exposure, to evaluate the protective capacity of monovalent or bivalent vaccines against homologous and heterologous virulent Leptospira in hamster. Leptospire were subjected to heat inactivation, or to LPS extraction with butanol and in some cases further inactivation with formaldehyde. Hamsters were immunized and challenged with homologous or heterologous virulent serovars, blood and organs were collected from the survivors for bacterial quantification, chemokine evaluation, and analysis of sera antibody reactivity and cross-reactivity by Western blot. Immunization with either heated or low LPS vaccines with serovar Copenhageni or Canicola resulted in 100% protection of the animals challenged with homologous virulent bacteria. Notably, different from the whole-cell vaccine, the low LPS vaccines produced with serovar Canicola provided only partial protection in heterologous challenge with the virulent Copenhageni serovar. Immunization with bivalent formulation results in 100% protection of immunized animals challenged with virulent serovar Canicola. All vaccines produced were able to eliminate bacteria from the kidney of challenged animals. All the vaccines raised antibodies capable to recognize antigens of serovars not present in the vaccine formulation. Transcripts of IFNγ, CXCL16, CCL5, CXCL10, CXCR6, and CCR5, increased in all immunized animals. Conclusion: Our results showed that bivalent vaccines with reduced LPS may be an interesting strategy for protection against heterologous virulent serovars. Besides the desirable multivalent protection, the low LPS vaccines are specially promising due to the expected lower reatogenicity.

钩端螺旋体属的致病性螺旋体是钩端螺旋体病的病原体。抗钩端螺旋体感染的细胞疫苗通常主要引起针对制剂中存在的血清型的LPS抗原的应答。没有合适的候选蛋白质能够替代全细胞疫苗，因此需要新的疫苗开发方法来改善钩端螺旋体病的预防。我们的目标是基于LPS去除和蛋白质抗原暴露的保守性，开发一种不依赖全细胞疫苗的猪，以评估单价或二价疫苗对仓鼠中同源和异源强毒钩端螺旋体的保护能力。钩藤进行热灭活，或用丁醇进行LPS萃取，在某些情况下用甲醛进一步灭活。免疫仓鼠并用同源或异源的强力血清型攻击，从幸存者中收集血液和器官用于细菌定量，趋化因子评估，并通过蛋白质印迹分析血清抗体反应性和交叉反应性。用血清型Copenhaci或Canicola的加热或低LPS疫苗免疫可对受到同源有毒细菌攻击的动物提供100％的保护。值得注意的是，与全细胞疫苗不同，用Canicola血清型生产的低LPS疫苗仅能在强毒的Copenhageni血清型的异源攻击中提供部分保护。使用二价制剂免疫可对受强毒血清型Canicola攻击的免疫动物提供100％的保护。所生产的所有疫苗都能够消除受攻击动物肾脏的细菌。所有疫苗都产生了能够识别疫苗制剂中不存在的血清抗原的抗体。在所有免疫的动物中，IFNγ，CXCL16，CCL5，CXCL10，CXCR6和CCR5的转录本均增加。结论：我们的结果表明，LPS降低的二价疫苗可能是一种针对异源性强毒血清的保护的有趣策略。除了理想的多价保护，由于预期的较低的致畸性，低LPS疫苗特别有前途。