Modification of HPV 16 E7 genes: correlation between the level of protein expression and CTL response after immunization of C57BL/6 mice
Immunization with a codon-optimized HPV 16 E7 gene was shown to yield higher levels of E7-specific cytotoxic T cells [Liu WJ, Gao F, Zhao KN, Zhao W, Fernando GJ, Thomas R, et al. Codon modified human papillomavirus type 16 E7 DNA vaccine enhances cytotoxic T-lymphocyte induction and anti-tumour act...
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Published in | Vaccine Vol. 23; no. 9; pp. 1149 - 1157 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
Oxford
Elsevier Ltd
19.01.2005
Elsevier |
Subjects | |
Online Access | Get full text |
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Summary: | Immunization with a codon-optimized HPV 16
E7 gene was shown to yield higher levels of E7-specific cytotoxic T cells [Liu WJ, Gao F, Zhao KN, Zhao W, Fernando GJ, Thomas R, et al. Codon modified human papillomavirus type 16
E7 DNA vaccine enhances cytotoxic T-lymphocyte induction and anti-tumour activity. Virology 2002;301:43]. Here, we sought to verify the hypothesis that there is a direct correlation between the level of protein expression and immunogenicity in mice. We generated HPV 16
E7 expression plasmids where the genes were inserted either as authentic sequence (wt) or after optimizing the codons for use in mammalian cells (opt). For enhancement of translation of the
E7 gene a 5′ Kozak sequence (K) was added. Transfection experiments revealed the strength of expression in the order of
E7opt
+
K,
E7opt
−
K,
E7wt
+
K and
E7wt
−
K. After immunization of C57/B6 mice we observed an equally strong CD8
+
T-cell response with the
E7opt plasmids (+ or −K), followed by the
E7wt
+
K and
E7wt
−
K DNAs. The same difference in efficiency was obtained in tumor protection experiments. Regression of pre-existing tumors and CTL activity was observed only with the
E7opt
+
K plasmid. From these data, we conclude that the level of protein expression correlates with the efficiency of CTL response and hence testing by transfection of cells in culture may allow a pre-selection of expression plasmids prior to DNA immunization. |
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Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 ObjectType-Article-1 ObjectType-Feature-2 |
ISSN: | 0264-410X 1873-2518 |
DOI: | 10.1016/j.vaccine.2004.08.027 |