RESUMO
Immunization with plasmid DNA vectors represents a promising new approach to vaccination. It has been shown to elicit humoral and cellular immunity and protection in various infection models. Here, we assessed the immunogenicity and protective efficacy of a DNA vaccine vector encoding the antigen 85A (Ag85A) of Mycobacterium tuberculosis. Since intramuscular (i.m.) immunization with naked DNA requires considerable amounts of DNA in order to be effective, we evaluated a strategy to reduce the amount of DNA needed. To this end, we used Ag85A DNA adsorbed onto cationic poly(DL-lactide-co-glycolide) (PLG) microparticles and observed similar levels of protection against aerosol challenge in mice using doses of PLG-DNA two orders of magnitude lower than with naked DNA itself.
Assuntos
Vacinas contra a Tuberculose/administração & dosagem , Vacinas contra a Tuberculose/uso terapêutico , Tuberculose/prevenção & controle , Adsorção , Animais , Primers do DNA , Sistemas de Liberação de Medicamentos , Injeções Intramusculares , Interferon gama/metabolismo , Ácido Láctico , Camundongos , Camundongos Endogâmicos BALB C , Microesferas , Mycobacterium bovis/genética , Mycobacterium bovis/imunologia , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/imunologia , Ácido Poliglicólico , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Polímeros , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Baço/citologia , Baço/metabolismo , Baço/microbiologia , Linfócitos T/metabolismo , Tuberculose/imunologia , Tuberculose/microbiologia , Vacinas contra a Tuberculose/química , Vacinas de DNA/administração & dosagem , Vacinas de DNA/química , Vacinas de DNA/uso terapêuticoRESUMO
The Mycobacterium bovis BCG vaccine for commercial use is classically produced as surface pellicles by culture on synthetic medium. Under these conditions, reproducibility of the cultures and quality assessment are hampered by slow growth of the bacilli, the formation of bacterial aggregates and a high proportion of dead bacilli after processing and final formulation of the vaccine. Here, we established dispersed cultures of M. bovis BCG in synthetic media in small-scale bioreactors. These cultures allow recording and adjusting of culture parameters and give rise to single bacilli with a high degree of live bacteria. In the murine model, bioreactor-grown M. bovis BCG exhibited slightly stronger replication and persistence than the vaccine produced under the classical conditions. The protective efficacy against challenge with M. tuberculosis was identical for both vaccine preparations.
