A humanized IgG but not IgM antibody is effective in prophylaxis and therapy of yellow fever infection in an AG129/17D-204 peripheral challenge mouse model

Arthropod-borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, 80523, USA.
Antiviral research (Impact Factor: 3.94). 02/2012; 94(1):1-8. DOI: 10.1016/j.antiviral.2012.02.001
Source: PubMed


Yellow fever virus (YFV), a member of the genus Flavivirus, is a mosquito-borne virus found in tropical regions of Africa and South America that causes severe hepatic disease and death in humans. Despite the availability of effective vaccines, YFV is responsible for an estimated 200,000 cases and 30,000 deaths annually. There are currently no prophylactic or therapeutic strategies approved for use in human YFV infections. Furthermore, implementation of YFV 17D-204 vaccination campaigns has become problematic due to an increase in reported post-vaccinal adverse events. We have created human/murine chimeric MAbs of a YFV-reactive murine monoclonal antibody (mMAb), 2C9, that was previously shown to protect mice from lethal YFV infection and to have therapeutic activity. The new chimeric (cMAbs) were constructed by fusion of the m2C9 IgG gene variable regions with the constant regions of human IgG and IgM and expressed in Sp2 murine myelomas. The 2C9 cMAbs (2C9-cIgG and 2C9-cIgM) reacted with 17D-204 vaccine strain in an enzyme-linked immunosorbent assay and neutralized virus in vitro similarly to the parent m2C9. Both m2C9 and 2C9-cIgG when administered prophylactically 24h prior to infection protected AG129 mice from peripheral 17D-204 challenge at antibody concentrations ≥1.27 μg/mouse; however, the 2C9-cIgM did not protect even at a dose of 127 μg/mouse. The 17D-204 infection of AG129 mice is otherwise uniformly lethal. While the m2C9 was shown previously to be therapeutically effective in YFV-infected BALB/c mice at day 4 post-infection, the m2C9 and 2C9-cIgG demonstrated therapeutic activity only when administered 1 day post-infection in 17D-204-infected AG129 mice.

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    • "In contrast, YFV-17D-immune subjects were fully protected against YFV-17D that express the homologous envelope proteins (38, 40). The protection in this case may be largely due to neutralizing antibodies since prior studies have demonstrated that adoptive transfer of immune serum alone provides partial to full protective immunity against lethal YFV in rhesus macaques (RM) (41), hamsters (42), and immunodeficient mice (43). "
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    • "Appreciable results were also obtained when both murine 2C9 and 2C9-cIgG were administered 24 hours post-infection, with the survival of 70% and 20% of mice, respectively. Viral presence was not detected in surviving mice [60]. "
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