Activation of innate immunity, inflammation, and potentiation of DNA vaccination through mammalian expression of the TLR5 agonist flagellin.
Improving DNA vaccination remains a fundamental goal in vaccine research. Theoretically, this could be achieved by molecules encoded by DNA capable of activating TLRs to mimic inflammatory responses generated by infection. Therefore, we constructed an expression vector that allows mammalian cells to express the TLR5 agonist flagellin (FliC) at the cell surface. In vitro, cell lines expressing FliC stimulated production of proinflammatory cytokines and the up-regulation of costimulatory molecules on monocytes. Mice given the FliC expression vector intradermally exhibited site-specific inflammation and, in combination with vectors expressing Ags, developed dramatic increases in Ag-specific IgG as well as IgA. Surprisingly, mice also developed strong Ag-specific MHC class I-restricted cellular immunity. To determine whether vaccination using FliC vectors could elicit protective immunity to an infectious agent, mice were given dermal injections of FliC expression vector together with a vector encoding the influenza A virus nucleoprotein. This vaccination strategy elicited protective immunity to lethal influenza A virus infection. These results demonstrate that expression of DNA-encoded TLR agonists by mammalian cells greatly enhance and broaden immune responses, imposing new possibilities on DNA vaccination to infectious agents and cancer.
Applequist
Steven E
SE
Center for Infectious Medicine, F59, Department of Medicine, Karolinska Institutet, Karolinska University Hospital at Huddinge, Stockholm, Sweden. steapp@mbox.ki.se
Rollman
Erik
E
Wareing
Mark D
MD
Lidén
Martin
M
Rozell
Björn
B
Hinkula
Jorma
J
Ljunggren
Hans-Gustaf
HG
D000818:Animals; D000956:Antigens, Viral / Q000008:administration & dosage / Q000235:genetics; D002460:Cell Line; D005408:Flagellin / Q000008:administration & dosage / Q000235:genetics / Q000494:pharmacology*; D005822:Genetic Vectors; D006801:Humans; D007111:Immunity, Cellular / Q000187:drug effects; D007113:Immunity, Innate / Q000187:drug effects*; D007070:Immunoglobulin A / Q000096:biosynthesis; D007074:Immunoglobulin G / Q000096:biosynthesis; D007249:Inflammation / Q000139:chemically induced*; D009980:Influenza A virus / Q000276:immunology; D007251:Influenza, Human / Q000517:prevention & control / Q000628:therapy; D051379:Mice; D008810:Mice, Inbred C57BL; D019590:Nucleocapsid Proteins; D009698:Nucleoproteins / Q000008:administration & dosage / Q000235:genetics; D016601:RNA-Binding Proteins / Q000008:administration & dosage / Q000235:genetics; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000235:genetics* / Q000494:pharmacology; D014758:Viral Core Proteins / Q000008:administration & dosage / Q000235:genetics
D000956:Antigens, Viral; D007070:Immunoglobulin A; D007074:Immunoglobulin G; C048842:NP protein, Influenza A virus; D019590:Nucleocapsid Proteins; D009698:Nucleoproteins; D016601:RNA-Binding Proteins; D019444:Vaccines, DNA; D014758:Viral Core Proteins; D005408:Flagellin