The ΔfbpA attenuated candidate vaccine from Mycobacterium tuberculosis, H37Rv primes for a stronger T-bet dependent Th1 immunity in mice - 27/12/11
Summary |
The ΔfbpA candidate vaccine derived from Mycobacterium tuberculosis (H37Rv) (Mtb) protects mice better than BCG against tuberculosis, and we investigated the hypothesis that ΔfbpA may induce a stronger Th1 immunity. Since T-bet transcription factor regulates Th1 immunity, mice infected with ΔfbpA, BCG vaccine and related mycobacteria were analyzed for T-bet positive T cells. Mouse dendritic cells (DCs) or macrophages were also pulsed with excretory-secreted antigens (ES; Antigen-85B, ESAT-6 and CFP10) and cocultured with T cells from immunized or naïve mice and tested for in vitro induction of T-bet and IFN-γ. In both models, ΔfbpA mutant induced a stronger response of T-bet+CD4 T cells, which correlated with an increased expansion of IFN-γ+CD4 T cells in vivo and in vitro. When DCs pulsed with ES antigens were allowed to stimulate T cells, ESAT-6 and CFP-10 failed to induce a recall expansion of T-bet+IFN-γ+CD4 T cells from BCG vaccinated mice. Thus, deletion of RD1 in BCG seems to reduce its ability to induce T-bet and induce stronger Th1 immunity. Finally, mice were vaccinated with ΔfbpA and BCG and challenged with virulent Mtb for evaluation of protection and T cell expansion. ΔfbpA vaccinated mice showed a rapid and stronger expansion of CD4+CXCR3+ IFN-γ+ T cells in the lungs of Mtb challenged mice, compared to those which had BCG vaccine. ΔfbpA immunized mice also showed a better decline of the Mtb bacterial counts of the lungs. Mtb derived ΔfbpA candidate vaccine therefore induces qualitatively better T-bet dependent Th1 immunity than BCG vaccine.
Le texte complet de cet article est disponible en PDF.Keywords : Mycobacterium, Tuberculosis, Vaccine, ΔfbpA, Mouse, BCG, T-bet, CXCR3
Abbreviations : Mtb-H37Rv, ΔfbpA, BCG, Ag85B, ESAT-6, CFP-10
Plan
Vol 91 - N° S1
P. S96-S104 - décembre 2011 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
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