It seems that the appearance of 65 kDa protein in immunoblotting (Figure 5A) was due to non-specific reactions because EVP4593 in vitro normal hamster urine had the 65 kDa protein (Figure 5A) and normal rabbit serum also reacted with such protein (data not shown). During 0–6 days after infection, urine still appeared normal and leptospires were not shed in urine. Further study is needed to identify these proteins. Hamsters and humans also have enzymes similar to leptospiral HADH. The amino acid sequences of this protein are conserved among Leptospira spp., however, the amino acid homology between

hamster or human and L. interrogans serovar Copenhageni were only 25.08% or 32.44%, respectively. It is, therefore, expected that the antisera against leptospiral HADH cannot recognize the protein of hamsters. Several studies previously reported that the abundant proteins or LPS on the surface of outer membrane were suitable as targets for PRI-724 supplier vaccine and diagnosis of leptospirosis such as outer membrane proteins [38, 39], LIC11207 [40], OmpL1 [41, 42], MPL17 and MPL21 [43], HbpA [44], LigA [45], LP29 and LP49 [46], LipL32 [47–50], LipL21 [50, 51], LipL41 [42], flagellin protein [52]. Moreover, it was also reported that different proteins were expressed in leptospires shed in chronically selleck chemicals infected rats compared to leptospires cultured in vitro[53],

and that the leptospires in rat urine affected urinary protein composition [54]. However, we were not able to identify any of the previously reported leptospiral proteins in the urine either by immunoblotting with anti-L. interrogans pAb or MS/MS analysis. The polyclonal antibodies were produced in rabbits, and we confirmed that proteins were recognized by this antibody using immunoblotting and MS/MS analyses. The antibody could recognize some membrane proteins such as LipL32 MycoClean Mycoplasma Removal Kit and LipL41 when bacterial cells were used for immunoblotting (unpublished data). However, leptospiral membrane lipoproteins were not detected in the urine, probably due to their low concentration. These results suggest that not

only membrane proteins but also intracellular proteins, such as HADH, can be used as candidates for leptospirosis diagnosis. We investigated the changes in the attributes of hamster urine prior to infection and a day just before death in a hamster model, and found that the conditions drastically changed one day prior to death. The pH of hamster urine is usually about 8, and it was found to have become acidic before death (Figure 1B). Urinary test results suggest that this acidification was caused by renal failure, like nephritis. Hamster urine is usually cloudy due to a high concentration of calcium carbonate [55]. But, it became clear on the day prior to death due to leptospirosis. Calcium carbonate is deposited in alkali conditions, and dissolved in acidic conditions.