MORÓN VÍCTOR GABRIEL
Congresos y reuniones científicas
Título:
TLR9 activation is required for cytotoxic response elicited by baculovirus capsid display
Autor/es:
MARÍA INÉS CRESPO; PAULA MOLINARI; GUIDO N. MOLINA; BELKYS A. MALETTO; OSCAR TABOGA; IGNACIO CEBRIAN; G MORON
Lugar:
Mar del Plata
Reunión:
Congreso; LXX Reunión de la Sociedad Argentina de Inmunología. 3ra Congreso Franco-Argentino de Inmunología; 2022
Institución organizadora:
Sociedad Argentina de Inmunología
Resumen:
The baculovirus (BV) infects lepidopteran as natural hosts and represents
an efficient vector for vaccine development. We showed that
BV expressing OVA in its capsid (BVOVA) improved the immune
response by eliciting CD8+ T cell activation. BVs enter intact into
subcellular compartments of dendritic cells (DC) where both viral
surface proteins and capsid follow separate intracellular routes, allowing
the viral capsid containing the foreign Ag to reach the cytosol.
In this study, we analyzed the intracellular mechanisms involved
in CD8+ T cell activation by BVOVA. We first evaluated if the BV
GP64-fusogenic protein is required for OVA cross-presentation by
pretreating BVOVA with an anti-GP64 neutralizing antibody. In this
case, infected splenic DCs failed to activate the B3Z CD8+ T cell
hibridoma, specific for the MHCI(Kb)-OVA257–264. Moreover, T cell activation
was inhibited when DCs were treated with lactacystin, indicating
that proteasome is required for efficiently cross-presentation.
We then analyzed the dependence of TLR9 and STING signaling by
infecting DCs with BVOVA in the presence of H151, a STING inhibitor,
or IRS869, a TLR9 signaling inhibitor. Only the incubation with
IRS869 blocked B3Z activation by DCs. We also evaluated whether
TLR9 is required to induce proliferation of naïve CD8+ T cells
using BVOVA-infected DCs from WT and TLR9-/- mice. We found that TLR9-/- DCs cannot activate naïve CD8+ T cells efficiently. Also,
TLR9-/- mice fail to generate an OVA-specific cytotoxic response
after BVOVA injection. Finally, using IFNAR-/- mice we observed
type I IFN are not required for cytotoxic response induction. In this
work, we found that the viral envelope fuses with the endosomal
membrane allowing the viral capsid exits to cytosol for proteasomal
degradation. During this BVOVA intracellular trafficking, endosomal
TLR9 signaling in DCs is triggered, thereby stimulating the presentation
of the MHCI/OVA257-264 complex to CD8+ T cells, which activate
into CTL.
an efficient vector for vaccine development. We showed that
BV expressing OVA in its capsid (BVOVA) improved the immune
response by eliciting CD8+ T cell activation. BVs enter intact into
subcellular compartments of dendritic cells (DC) where both viral
surface proteins and capsid follow separate intracellular routes, allowing
the viral capsid containing the foreign Ag to reach the cytosol.
In this study, we analyzed the intracellular mechanisms involved
in CD8+ T cell activation by BVOVA. We first evaluated if the BV
GP64-fusogenic protein is required for OVA cross-presentation by
pretreating BVOVA with an anti-GP64 neutralizing antibody. In this
case, infected splenic DCs failed to activate the B3Z CD8+ T cell
hibridoma, specific for the MHCI(Kb)-OVA257–264. Moreover, T cell activation
was inhibited when DCs were treated with lactacystin, indicating
that proteasome is required for efficiently cross-presentation.
We then analyzed the dependence of TLR9 and STING signaling by
infecting DCs with BVOVA in the presence of H151, a STING inhibitor,
or IRS869, a TLR9 signaling inhibitor. Only the incubation with
IRS869 blocked B3Z activation by DCs. We also evaluated whether
TLR9 is required to induce proliferation of naïve CD8+ T cells
using BVOVA-infected DCs from WT and TLR9-/- mice. We found that TLR9-/- DCs cannot activate naïve CD8+ T cells efficiently. Also,
TLR9-/- mice fail to generate an OVA-specific cytotoxic response
after BVOVA injection. Finally, using IFNAR-/- mice we observed
type I IFN are not required for cytotoxic response induction. In this
work, we found that the viral envelope fuses with the endosomal
membrane allowing the viral capsid exits to cytosol for proteasomal
degradation. During this BVOVA intracellular trafficking, endosomal
TLR9 signaling in DCs is triggered, thereby stimulating the presentation
of the MHCI/OVA257-264 complex to CD8+ T cells, which activate
into CTL.
