Plasmid DNA-recombinant Opc protein complexes for nasal DNA immunization

The nasal mucosa may provide a simple, non-invasive route to deliver DNA en coding genes that stimulate a specific immune response. Based on this, a ne w approach using pCMV beta -gal plasmid DNA complexed to the Ope meningococ cal outer membrane protein was assayed for. Optimal conditions of interacti on were established between recombinant Ope protein and pCMV beta -gal plas mid DNA. Complexes were fully characterized by electrophoresis analysis. DN Ase resistance assay and transmission electron microscopy. DNA-protein comp lexes were also evaluated in in vitro transfection experiments. After the c haracterisation of complexes. Balb/c mice were intranasal (i.n.) and intram uscularly (i.m.) immunized. The humoral immune response against beta -galac tosidase was measured by ELISA. The proliferative response in the spleen ly mph nodes was also measured. Complexes administered by i.n. route induced b oth systemic and mucosal antibody responses. This behavior was not observed with the naked DNA. Finally, a lymphoproliferative response specific to be ta -galactosidase induced by DNA-protein complexes was also detected. (C) 2 001 Elsevier Science Ltd. All rights reserved.