Immune-enhanced effect of Iris polysaccharide is protective against leptospirosis

Leptospirosis, caused by pathogenic Leptospira species, is an essential but neglected zoonosis. There are more than 300 serovars of Leptospira, while inactivated bacteria offers only short-term serovar-specific protection. Leptospirosis treatment mainly dependent on the use antibiotics. However, side effects antibiotics and risk antibiotic resistance remain major problems. Thus, alternative agents which fewer humans efficient in leptospirosis would be welcome. Many studies have reported that polysaccharides could used as immunostimulants treating infection cancer. In this study, we examined protective effect isolated from Iris against leptospirosis. To our knowledge, it first time to report (IP) immunostimulant infection. The results showed IP significantly increased survival rate hamsters challenged a lethal dose leptospires. Besides, tissue injury leptospiral load were reduced IP-treated group compared with untreated at 4 days post-infection (p.i.). Intriguingly, sustained intense immune response p.i. analyzed qPCR. exhibited gene expression TLR2 TLR4 was coinjected leptospires infected controls. And IL-1β TNF-α also up-regulated after treatment, except kidney. Our not broaden medicinal value Iris, provide competent candidate for control