construction of a eukaryotic plasmid encoding bacillus anthracis protective antigen, a candidate for dna vaccine

background: dna immunization with plasmid dna encoding bacterial, viral, parasitic and tumor antigens has been reported to trigger protective immunity. objective: to evaluate the use of a dna immunization strategy for protection against anthrax, a plasmid was constructed. methods: the partialsequence of protective antigen of bacillus anthracis, amino acids 175-764, as a potent immunogenic target was selected. the dna encoding this segment was utilized in the construction of pcdna3.1+pa plasmid. after intramuscular injection of rats with pcdna3.1+pa plasmid, the expression of pa was assessed by rt-pcr and immunohistochemistry at rna and protein levels, respectively. we also evaluated the presence of anti-pa antibodies in sera of immunized mice with pcdna3.1+pa construct using immunoblotting. results: the integrity of pcdna3.1+pa construct was confirmed with restriction analysis and sequencing. the expression of pa was detected at rna and protein levels. the presence of anti-pa antibodies in immunized mice with pcdna3.1+pa construct was also confirmed. conclusion: our results indicate that pcdna3.1+pa eukaryotic expressing vector could express pa antigen, induce antibody response and may be used as a candidate for dna vaccine against anthrax.