title: Modulating gene expression using DNA vaccines with different 3'-UTRs influences antibody titer, seroconversion and cytokine profiles.
abstract: To determine if modulating the amount of foreign antigen produced by a DNA vaccine can influence the overall intensity and cytokine polarization of the ensuing immune response, three different plasmids, each encoding the hepatitis B (HB) surface antigen, were constructed. In each construct, HBs gene expression was driven by the cytomegalovirus immediate early promoter, but differed in the 3'-untranslated regions (3'-UTR) containing the polyadenylation sequence. These 3'-UTR sequences were derived from either the hepatitis B virus (HBVpA), bovine growth hormone (BGHpA), or rabbit beta-globin (betapA). BALB/c mice were immunized intramuscularly with equimolar amounts of each plasmid and blood was collected bi-weekly. Following immunization, total IgG titers correlated with in vitro antigen production levels (from transfected CHO cells), as evidenced by the following response pattern: HBVpA>BGHpA>>betapA. All groups demonstrated a heavy bias toward a Th1 immune response, as evidenced by high serum IgG2a/IgG1 ratios and the predominance of IFN-gamma over IL-4 secretion from cultured splenocytes. In addition, the HBVpA construct resulted in a seroconversion rate of 100%, in comparison to 40-50% in the BGHpA, and 0% in the betapA group. Surprisingly, splenocytes isolated from mice immunized with the betapA construct secreted the highest levels of IFN-gamma. Taken together, these findings suggest that altering the level of gene expression not only affects the overall titer and seroconversion rates of vaccinated animals, but also may play a role in modulating cytokine profiles.
authors.affiliation: Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA.
authors.forename: John W
authors.initials: JW
authors.lastname: Zinckgraf
authors.forename: Lawrence K
authors.initials: LK
authors.lastname: Silbart
mesh_terms: D020413:3' Untranslated Regions / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology*; D000818:Animals; D016207:Cytokines / Q000096:biosynthesis / Q000235:genetics*; D005260:Female; D020869:Gene Expression Profiling / Q000379:methods; D006510:Hepatitis B Antibodies / Q000096:biosynthesis* / Q000097:blood; D006515:Hepatitis B virus / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D007074:Immunoglobulin G / Q000096:biosynthesis / Q000097:blood; D051379:Mice; D008807:Mice, Inbred BALB C; D010957:Plasmids / Q000096:biosynthesis; D011061:Poly A / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D012698:Serologic Tests; D019444:Vaccines, DNA / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology*
chemical_list: D020413:3' Untranslated Regions; D016207:Cytokines; D006510:Hepatitis B Antibodies; D007074:Immunoglobulin G; D012333:RNA, Messenger; D019444:Vaccines, DNA; D011061:Poly A