Use of N-trimethyl chitosan for intranasal delivery of DNA encoding M2e-HSP70c in mice

Abstract

BACKGROUND: Influenza outbreak has become a great lifethreatening<br />disease in the world. Nasal vaccines can induce<br />systemic IgG and mucosal IgA antibody responses, which<br />establish two layers of immune defense against the infectious<br />pathogens like influenza. Mucosal vaccines must overcome<br />several limitations, including the mucociliary clearance and<br />inefficient uptake of soluble antigens. Therefore, nasal vaccines<br />require potent adjuvants and delivery systems. OBJECTIVES: In<br />this study we evaluated the effect of N-trimethyl chitosan (TMC)<br />as a potent vehicle for DNA encoding M2e/HSP70c in order for<br />intranasal administration in mice. METHODS:Ectodomain of the<br />conserved influenza matrix protein 2 (M2e), which has been<br />found to induce heterosubtypic immunity, was fused to<br />HSP70359-610 or C-terminus of Mycobacterium tuberculosis<br />HSP70 (HSP70c) in pcDNA3.1 vector (pcDNA/M2e-HSP70c)<br />and then encapsulated into a derivative of chitosan, N-trimethyl<br />chitosan (TMC). After encapsulation of the plasmid, physical<br />properties of the particles were investigated using Zetasizer®<br />3000 the particles were then administered through the intranasal<br />delivery in BALB/c mice. RESULTS: It was found that the<br />particles had a size ranging between 90-120nm and positive<br />surface charge. The intranasal immunization with M2e-<br />HSP70c+TMC in BALB/c mice significantly induced higher<br />M2e specific IgG than those induced in control groups<br />(pcDNA/M2e-HSP70c without TMC, pcDNA/M2e, bearing<br />M2e alone, and PBS).CONCLUSIONS: The present study showed<br />that the encapsulation of M2e/ HSP70c into N-trimethyl<br />chitosan (TMC) could strongly induce the humoral immune<br />response against the M2e-HSP70c plasmid without lowering the<br />adjuvant efficacy of HSP70c.