Influence of codon usage on the immunogenicity of a DNA vaccine against tetanus

Two related DNA vaccine vector plasmids, harbouring either wild-type (pcDNA 3/ntetC) or synthetic codon optimised (pcDNA3/stetC) DNA encoding fragment C (TetC) of tetanus toxin were constructed. COS-7 cells transformed with pc DNA3/ stetC reproducibly expressed higher levels of TetC than similar cells transformed with pcDNA3/ntetC. BALB/c mice immunised intramuscularly with pcDNA3/stetC produced significantly higher levels of anti-TetC antibodies i n their serum in the weeks following vaccination compared to mice immunised with pcDNA3/ntetC, even when differences in the CpG content between the tw o sequences were controlled for using non-expressing DNA. (C) 2000 Elsevier Science Ltd. All rights reserved.