Browsing by Author "Herbert, Andrew S."

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    Cytokine-bearing Influenza Vaccine: Adjuvant Potential of Membrane-bound Immunomodulators
    Herbert, Andrew S. (Virginia Tech, 2009-04-27)
    Influenza epidemics continue to cause morbidity and mortality within the human population despite widespread vaccination efforts. This, along with the ominous threat of an avian influenza pandemic (H5N1), demonstrates the need for a much improved, more sophisticated influenza vaccine. Our group has developed an in vitro model system for producing a membrane-bound Cytokine-bearing Influenza Vaccine (CYT-IVAC). Numerous cytokines are involved in directing both innate and adaptive immunity and it is our goal to utilize the properties of individual cytokines and other immunomodulatory proteins to create a more immunogenic vaccine. Here we report methodologies for the construction of membrane-bound cytokine fusion constructs in which our cytokine of interest (mouse GM-CSF, mouse IL-2, mouse IL-4) was fused to the membrane anchoring regions of viral Hemagglutinin (HA). Progeny virions, produced from influenza infected MDCK cells expressing membrane-bound cytokines, readily incorporated membrane-bound cytokines during budding and these cytokines on the virus particles retained bioactivity following viral inactivation. In vivo vaccination studies in mice showed enhanced antibody titers and improved protection following lethal challenge in those mice vaccinated with IL-2 and IL-4-bearing CYT-IVAC's compared to the conventional wild-type vaccine without membrane-bound cytokines. In addition, the immune response induced by IL-2 and IL-4-bearing CYT-IVACs was skewed toward Th1 (cellular) mediated immunity compared to the Th2 (humoral) dominated response induced with wild-type vaccination. Cellular mediated immunity afforded by IL-2 and IL-4 CYT-IVACs was manifested as enhanced influenza specific T cell proliferation and activation. In conclusion, we have developed a novel methodology to introduce bioactive membrane-bound cytokines directly into virus particles in order to augment the immunogenicity of inactivated, whole virus influenza vaccines.
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    Incorporation of membrane-bound, mammalian-derived immunomodulatory proteins into influenza whole virus vaccines boosts immunogenicity and protection against lethal challenge
    Herbert, Andrew S.; Heffron, C. Lynn; Sundick, Roy; Roberts, Paul C. (2009-04-24)
    Background Influenza epidemics continue to cause morbidity and mortality within the human population despite widespread vaccination efforts. This, along with the ominous threat of an avian influenza pandemic (H5N1), demonstrates the need for a much improved, more sophisticated influenza vaccine. We have developed an in vitro model system for producing a membrane-bound Cytokine-bearing Influenza Vaccine (CYT-IVAC). Numerous cytokines are involved in directing both innate and adaptive immunity and it is our goal to utilize the properties of individual cytokines and other immunomodulatory proteins to create a more immunogenic vaccine. Results We have evaluated the immunogenicity of inactivated cytokine-bearing influenza vaccines using a mouse model of lethal influenza virus challenge. CYT-IVACs were produced by stably transfecting MDCK cell lines with mouse-derived cytokines (GM-CSF, IL-2 and IL-4) fused to the membrane-anchoring domain of the viral hemagglutinin. Influenza virus replication in these cell lines resulted in the uptake of the bioactive membrane-bound cytokines during virus budding and release. In vivo efficacy studies revealed that a single low dose of IL-2 or IL-4-bearing CYT-IVAC is superior at providing protection against lethal influenza challenge in a mouse model and provides a more balanced Th1/Th2 humoral immune response, similar to live virus infections. Conclusion We have validated the protective efficacy of CYT-IVACs in a mammalian model of influenza virus infection. This technology has broad applications in current influenza virus vaccine development and may prove particularly useful in boosting immune responses in the elderly, where current vaccines are minimally effective.