Protection against tuberculosis by a single intranasal administration of DNA-hsp65 vaccine complexed with cationic liposomes.
BACKGROUND
The greatest challenges in vaccine development include optimization of DNA vaccines for use in humans, creation of effective single-dose vaccines, development of delivery systems that do not involve live viruses, and the identification of effective new adjuvants. Herein, we describe a novel, simple technique for efficiently vaccinating mice against tuberculosis (TB). Our technique consists of a single-dose, genetic vaccine formulation of DNA-hsp65 complexed with cationic liposomes and administered intranasally.


RESULTS
We developed a novel and non-toxic formulation of cationic liposomes, in which the DNA-hsp65 vaccine was entrapped (ENTR-hsp65) or complexed (COMP-hsp65), and used to immunize mice by intramuscular or intranasal routes. Although both liposome formulations induced a typical Th1 pattern of immune response, the intramuscular route of delivery did not reduce the number of bacilli. However, a single intranasal immunization with COMP-hsp65, carrying as few as 25 microg of plasmid DNA, leads to a remarkable reduction of the amount of bacilli in lungs. These effects were accompanied by increasing levels of IFN-gamma and lung parenchyma preservation, results similar to those found in mice vaccinated intramuscularly four times with naked DNA-hsp65 (total of 400 microg).


CONCLUSIONS
Our objective was to overcome the significant obstacles currently facing DNA vaccine development. Our results in the mouse TB model showed that a single intranasal dose of COMP-hsp65 elicited a cellular immune response that was as strong as that induced by four intramuscular doses of naked-DNA. This formulation allowed a 16-fold reduction in the amount of DNA administered. Moreover, we demonstrated that this vaccine is safe, biocompatible, stable, and easily manufactured at a low cost. We believe that this strategy can be applied to human vaccines to TB in a single dose or in prime-boost protocols, leading to a tremendous impact on the control of this infectious disease.
Rosada
Rogério S
RS
Núcleo de Pesquisas em Tuberculose, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil.rosada@cpt.fmrp.usp.br
de la Torre
Lucimara Gaziola
LG
Frantz
Fabiani G
FG
Trombone
Ana P F
AP
Zárate-Bladés
Carlos R
CR
Fonseca
Denise M
DM
Souza
Patrícia R M
PR
Brandão
Izaíra T
IT
Masson
Ana P
AP
Soares
Edson G
EG
Ramos
Simone G
SG
Faccioli
Lúcia H
LH
Silva
Célio L
CL
Santana
Maria H A
MH
Coelho-Castelo
Arlete A M
AA
D000281:Administration, Intranasal; D000818:Animals; D001426:Bacterial Proteins / Q000008:administration & dosage* / Q000276:immunology; D018834:Chaperonin 60; D018833:Chaperonins / Q000008:administration & dosage* / Q000276:immunology; D005260:Female; D007110:Immunity, Active / Q000187:drug effects; D007117:Immunization, Secondary; D008081:Liposomes; D008213:Lymphocyte Activation / Q000187:drug effects / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D009169:Mycobacterium tuberculosis; D018417:Th1 Cells / Q000187:drug effects; D032581:Tuberculosis Vaccines / Q000008:administration & dosage*; D014397:Tuberculosis, Pulmonary / Q000276:immunology* / Q000382:microbiology / Q000517:prevention & control; D019444:Vaccines, DNA / Q000008:administration & dosage*
D001426:Bacterial Proteins; D018834:Chaperonin 60; D008081:Liposomes; D032581:Tuberculosis Vaccines; D019444:Vaccines, DNA; C074119:heat-shock protein 65, Mycobacterium; D018833:Chaperonins