Abstract
No countermeasures currently exist for the prevention or treatment of the severe sequelae of Filovirus (such as Ebola virus; EBOV) infection. To overcome this limitation in our biodefense preparedness, we have designed monoclonal antibodies (mAbs) which could be used in humans as immunoprotectants for EBOV, starting with a murine mAb (13F6) that recognizes the heavily glycosylated mucin-like domain of the virion-attached glycoprotein (GP). Point mutations were introduced into the variable region of the murine mAb to remove predicted human T-cell epitopes, and the variable regions joined to human constant regions to generate a mAb (h-13F6) appropriate for development for human use. We have evaluated the efficacy of three variants of h-13F6 carrying different glycosylation patterns in a lethal mouse EBOV challenge model. The pattern of glycosylation of the various mAbs was found to correlate to level of protection, with aglycosylated h-13F6 providing the least potent efficacy (ED(50) = 33 μg). A version with typical heterogenous mammalian glycoforms (ED(50) = 11 μg) had similar potency to the original murine mAb. However, h-13F6 carrying complex N-glycosylation lacking core fucose exhibited superior potency (ED(50) = 3 μg). Binding studies using Fcγ receptors revealed enhanced binding of nonfucosylated h-13F6 to mouse and human FcγRIII. Together the results indicate the presence of Fc N-glycans enhances the protective efficacy of h-13F6, and that mAbs manufactured with uniform glycosylation and a higher potency glycoform offer promise as biodefense therapeutics.
Highlights
No countermeasures currently exist for the prevention or treatment of the severe sequelae of Filovirus infection
Vaccines and monoclonal antibody antivirals have been identified as priorities by the U.S Department of Health and Human Services for protection from Ebola viruses (EBOV) used in acts of bioterrorism or war
13F6 is a murine monoclonal antibodies (mAbs), one of four highly protective antiEBOV glycoprotein (GP) mAbs identified at U.S Army Medical Research Institute of Infectious Diseases [2]. 13F6 recognizes the heavily glycosylated mucin-like domain of EBOV GP and was shown to provide 100% prophylactic and therapeutic protection in a mouse challenge model [2]
Summary
No countermeasures currently exist for the prevention or treatment of the severe sequelae of Filovirus (such as Ebola virus; EBOV) infection. To overcome this limitation in our biodefense preparedness, we have designed monoclonal antibodies (mAbs) which could be used in humans as immunoprotectants for EBOV, starting with a murine mAb (13F6) that recognizes the heavily glycosylated mucin-like domain of the virion-attached glycoprotein (GP). 13F6 recognizes the heavily glycosylated mucin-like domain of EBOV GP and was shown to provide 100% prophylactic and therapeutic protection in a mouse challenge model [2]. Comparing the efficacy of h-13F6 produced aglycosylated and glycosylated in two different production systems may help identify the mechanism(s) of action and a preferred manufacturing system for continued development of the EBOV therapeutic
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have