Viral protein complexed liposomes for intranasal delivery of hepatitis B surface antigen

The present work investigates prospective of recombinantly expressed influenza surface protein haemagglutinin (HA) complexed liposomes for intranasal delivery of HBsAg. Liposomes encapsulating HBsAg were prepared and complexed with HA. The prepared formulations were extensively characterized for vesicle size, polydispersity index, entrapment efficiency, HA complexation efficiency, in vitro release, etc. Stability of protein molecules was accessed by SDS-PAGE. The antigenicity of protein HBsAg was determined by EIA and the functional stability of HA was evaluated by haemagglutination assay. Subsequently, in vivo study was carried out to study their feasibility as nasal vaccine carriers. A significant and perdurable immune response was obtained following in vivo administration of the developed formulations that was comparable with alum adsorbed HBsAg administered intramuscularly. The HA complexed liposomal formulations elicited sIgA in mucosal secretions and also demonstrated cellular immune response both of which are not induced in the case of alum adsorbed HBsAg vaccine. Further, the HA complexed liposomes produced higher immune response as compared to plain liposomes that might be due to higher uptake of former as evidenced in microscopy study of nasal tissues. The higher cellular response generated by HA complexed liposomes may be possibly due to characteristic pH dependent fusion property of HA protein.