Generation of influenza virus from avian cells infected by Salmonella carrying the viral genome.
Domestic poultry serve as intermediates for transmission of influenza A virus from the wild aquatic bird reservoir to humans, resulting in influenza outbreaks in poultry and potential epidemics/pandemics among human beings. To combat emerging avian influenza virus, an inexpensive, heat-stable, and orally administered influenza vaccine would be useful to vaccinate large commercial poultry flocks and even migratory birds. Our hypothesized vaccine is a recombinant attenuated bacterial strain able to mediate production of attenuated influenza virus in vivo to induce protective immunity against influenza. Here we report the feasibility and technical limitations toward such an ideal vaccine based on our exploratory study. Five 8-unit plasmids carrying a chloramphenicol resistance gene or free of an antibiotic resistance marker were constructed. Influenza virus was successfully generated in avian cells transfected by each of the plasmids. The Salmonella carrier was engineered to allow stable maintenance and conditional release of the 8-unit plasmid into the avian cells for recovery of influenza virus. Influenza A virus up to 10⁷ 50% tissue culture infective doses (TCID50)/ml were recovered from 11 out of 26 co-cultures of chicken embryonic fibroblasts (CEF) and Madin-Darby canine kidney (MDCK) cells upon infection by the recombinant Salmonella carrying the 8-unit plasmid. Our data prove that a bacterial carrier can mediate generation of influenza virus by delivering its DNA cargoes into permissive host cells. Although we have made progress in developing this Salmonella influenza virus vaccine delivery system, further improvements are necessary to achieve efficient virus production, especially in vivo.
The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America; Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy/Health Sciences, Wayne State University, Detroit, Michigan, United States of America.
Xiangmin
X
Zhang
The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America.
Wei
W
Kong
The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America.
Soo-Young
SY
Wanda
The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America.
Wei
W
Xin
The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America.
Praveen
P
Alamuri
The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America; School of Life Science, Arizona State University, Tempe, Arizona, United States of America.
Roy
R
Curtiss
D000818:Animals; D002642:Chick Embryo; D002645:Chickens; D018920:Coculture Techniques; D004247:DNA / Q000008:administration & dosage / Q000235:genetics; D004285:Dogs; D016679:Genome, Viral; D005585:Influenza in Birds / Q000235:genetics* / Q000821:virology*; D061985:Madin Darby Canine Kidney Cells; D009154:Mutation; D010957:Plasmids; D012475:Salmonella / Q000235:genetics*
D004247:DNA