Efficacy of ormutivimab, a novel recombinant human anti-rabies monoclonal antibody, in post-exposure prophylaxis animal models.

Human rabies is a serious public health problem that can't be ignored. Rabies immune globulin (RIG) is an indispensable component of rabies post-exposure prophylaxis (PEP). However, current PEP relies on RIG purified from pooled human or equine plasma, which are either in chronic shortage or associated with safety concerns. Monoclonal antibodies have become widely accepted as safer and more cost-effective alternatives to RIG products in recent years. Here, we assessed the neutralization breadth of human monoclonal antibody ormutivimab and its protective efficacy in PEP models. Ormutivimab was able to neutralize a broad panel of Chinese prevalent street RABVs with neutralizing potency form 198-1487.6 IU/mL. Furthermore, ormutivimab offered comparable protection to that with HRIG both at standard doses (20 IU/kg) and higher doses (100 IU/kg and 200 IU/kg). The interference of ormutivimab on vaccine potency was also analyzed and found slightly reduced neutralizing antibody titers similar to HRIG. The broad-spectrum neutralization activities, highly protective potency, and rapid onset of action make ormutivimab an effective candidate for human rabies PEP.

Liver-specific ZP domain-containing protein (LZP) as a new partner of Tamm-Horsfall protein harbors on renal tubules.

Liver-specific ZP domain-containing protein (LZP) was recently identified as a secreted protein that is specifically expressed in liver. However, the physiological effects of LZP are largely unknown. In this study, we found that LZP was detectable in mouse kidneys, testes, ovaries and heart, in addition to liver. LZP was localized in the spermatid cells of testes, corpus luteum cells of ovaries, and cardiac muscle cells of heart. But the protein mainly anchored on the apical membrane of the thick ascending limb of the loop of Henle (TAL) cell in mouse kidney. In rat kidney LZP and Tamm-Horsfall protein (THP) were co-localized in TAL. The in vivo interaction between LZP and THP was confirmed in kidney and urine by co-immunoprecipitation assay, and the in vitro interaction was detected by GST pull-down assay, implying that the interaction could be independent on N-linked glycosylated modification of LZP. Surprisingly, LZPs with intramolecular disulfide bridges could self-interact, and then self-aggregate into spheres of varying sizes, but not polymerize into filaments. The finding that LZP might act as a new partner of THP would provide novel insights into renal functions related to THP and LZP, such as the urothelial permeability barrier and the host defense against the adhesion of pathogens.