Mouse anti-Human C1r monoclonal antibody, clone 370205

Leishmania donovani, the causative agent of Indian visceral leishmaniasis has to face several barriers of the immune system inside the mammalian host for its survival. The complement system is one of the first barriers and consists of a well-balanced network of proteases including S1A family serine proteases (SPs). Inhibitor of serine peptidases (ISPs) is considered as inhibitor of S1A family serine peptidases and is reported to be present in trypanosomes, including Leishmania. In our previous study, we have deciphered the role of ISPs [LdISP1 and L. donovani inhibitor of serine peptidases 2 (LdISP2)] in the survival of L. donovani inside the sandfly midgut. However, the role of theses ISPs in the survival of L. donovani inside mammalian host still remains elusive. In the present study, we have deciphered the inhibitory effect of LdISPs on the host complement S1A serine peptidases, such as C1r/C1s and MASP1/MASP2. Our study suggested that although both rLdISP1 and rLdISP2 inferred strong interaction with C1complex and MBL-associated serine proteases (MASPs) but rLdISP2 showed the stronger inhibitory effect on MASP2 than rLdISP1. Moreover, we found that rLdISP2 significantly reduces the formation of C3, C5 convertase, and membrane attacking complex (MAC) by lectin pathway (LP) resulting in significant reduction in serum mediated lysis of the parasites. The role of LdISP2 on neutrophil elastase-mediated C5aR signaling was also evaluated. Notably, our results showed that infection of macrophages with ISP2-overexpressed Leishmania parasites significantly induces the expression of C5aR both at the transcript and translational level. Simultaneously, infection with ISP2KD parasites results in downregulation of host PI3K/AKT phosphorylation and increased in IL-12 production. Taken together, our findings clearly suggest that LdISP2 promotes parasite survival inside host by inhibiting MAC formation and complement-mediated lysis via LP and by upregulation of C5aR signaling.

This research is focused on evaluating the efficiency and failure mechanism of joints using a komisen (Japanese traditional square key) of compressed sugi (Japanese ceder; Cryptomeria japonica D. Don), and to evaluate to what extend hozo-komisen (Japanese traditional mortise and tenon) joint strength is being influenced by the recovery of compressed sugi komisen when exposed to long term humidity cycling. Compressed sugi komisen showed a change of yield and rupture mode compared to shirakashi (Quercus myrsinaefolia Blume) komisen, as did the komisen inserting direction into the joint because it has characteristic and anisotropic properties. The compressed sugi komisen joint (C1R), when inserted according to the R-type, yielded by shear of the komisen and reached its maximum strength (P-max : 12.5 kN) just before rupture at 10 mm displacement at the tenon. The failure mode showed a different pattern, compared to the shirakashi komisen joint (SIR) where the central komisen yielded in bending. The strength of the compressed sugi komisen joint (C1RH) exposed to cyclic changes of humidity (40-80%RH) during two years increased in maximum strength, yield strength, and energy absorption. This is in contrast to the shirakashi komisen joint (C1RH) that showed a dramatic and remarkable strength decrease when exposed to the climatic environment.