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Updated: Aug 29, 2025
Production of Adeno-Associated Virus Vectors in Cell Stacks for Preclinical Studies in Large Animal Models
Published on: June 30, 2021
AAV-monoclonal antibody expression protects mice from Ebola virus without impeding the endogenous antibody response
Laura P van Lieshout1, Amira D Rghei1, Wenguang Cao2
1Department of Pathobiology, University of Guelph, Guelph, ON N1G 2W1, Canada.
Abstract:
Filoviruses cause severe hemorrhagic fever with case fatality rates as high as 90%. Filovirus-specific monoclonal antibodies (mAbs) confer protection in nonhuman primates as late as 5 days after challenge, and FDA-approved mAbs REGN-EB3 and mAb114 have demonstrated efficacy against Ebola virus (EBOV) infection in humans. Vectorized antibody expression mediated by adeno-associated virus (AAV) can generate protective and sustained concentrations of therapeutic mAbs in animal models for a variety of infectious diseases, including EBOV. Here we demonstrate that AAV6.2FF-mediated expression of murine IgG2a EBOV mAbs, 2G4 and 5D2, protects from mouse-adapted (MA)-EBOV infection with none of the surviving mice developing anti-VP40 antibodies above background. Protective serum concentrations of AAV6.2FF-2G4/AAV6.2FF-5D2 did not alter endogenous antibody responses to heterologous virus infection. AAV-mediated expression of EBOV mAbs 100 and 114, and pan-ebolavirus mAbs, FVM04, ADI-15878, and CA45, as human IgG1 antibodies conferred protection against MA-EBOV at low serum concentrations, with minimum protective serum levels as low as 2 μg/mL. Vectorized expression of murine IgG2a or human IgG1 mAbs led to sustained expression in the serum of mice for >400 days or for the lifetime of the animal, respectively. AAV6.2FF-mediated mAb expression offers an alternative to recombinant antibody administration in scenarios where long-term protection is preferable to passive immunization.
Insights
Adeno-associated virus (AAV) vector-mediated expression of filovirus-specific monoclonal antibodies (mAbs) provides long-term protection against Ebola virus (EBOV) infection in mice. This approach offers a promising alternative to traditional passive immunization for sustained therapeutic antibody levels.
Area of Science:
- Virology and Immunology
- Gene Therapy
- Infectious Diseases
Background:
- Filoviruses, including Ebola virus (EBOV), cause severe hemorrhagic fever with high fatality rates.
- Existing FDA-approved monoclonal antibodies (mAbs) show efficacy against EBOV, but require repeated administration.
- Adeno-associated virus (AAV) vector-mediated gene therapy can achieve sustained therapeutic protein expression.
Purpose of the Study:
- To evaluate the efficacy of AAV-mediated expression of EBOV-specific mAbs for protection against EBOV infection.
- To assess the durability and protective serum concentrations of vectorized mAbs.
- To explore AAV-mediated mAb expression as a long-term alternative to passive immunization.
Main Methods:
- AAV6.2FF vectors were used to express murine IgG2a and human IgG1 EBOV mAbs in mice.
- Mice were challenged with mouse-adapted EBOV (MA-EBOV) to assess protection.
- Serum antibody concentrations and endogenous antibody responses were monitored.
Main Results:
- AAV6.2FF-mediated expression of EBOV mAbs 2G4 and 5D2 conferred protection against MA-EBOV infection.
- Low serum concentrations (as low as 2 μg/mL) of vectorized human IgG1 mAbs were protective.
- Sustained mAb expression was observed for over 400 days or for the lifetime of the animals.
Conclusions:
- AAV-mediated expression of EBOV mAbs provides robust and long-lasting protection against filovirus challenge.
- This gene therapy approach offers a viable alternative to repeated recombinant antibody infusions.
- Vectorized antibody expression holds potential for durable protection against EBOV and potentially other infectious diseases.
