Antibody responses induced by mucosal DNA vaccine encoding the codon-optimized F protein of human respiratory syncytial virus (RSV) delivered with attenuated Salmonella typhimurium

Abstract:

Abstract:［Objective］ In order to investigate antibody responses by musosal DNA vaccines encoding the codon-optimized F protein of human respiratory syncytial virus (RSV) delivered with attenuated Salmonella typhimurium aroA strain SL7207 (SL7207) via intranasal or intragastric routes．［Methods］After the codon-optimized F gene was synthesized，we constructed eukaryotic expression plasmid pcDNA3.1/Fsyn and transformed it into SL7207 to get recombinant SL7207 of SL7207/pcDNA3.1/Fsyn．Then，SL7207/pcDNA3.1/Fsyn was exploited to evaluate its immunogenicity in BALB/c mice administered intranasally or intragastrically． The resultant serum and mucosal antibody responses were analyzed by indirect ELISA． ［Results］Compared with intragastric immunization group，intranasal immunization group achieved higher level of RSV specific serum IgG and secretion IgA (SIgA)(P＜0.05)．Moreover，F protein expressed by the codon-optimized F gene of Fsyn was of elevated immunogenicity，compared with wild type F (Fwt)(P＜0.05)．［Conclusion］ Intranasal immunization and codon optimization approaches can improve antibody responses of RSV DNA vaccine delivered by attenuated Salmonella typhimurium aroA strain SL7207．