INVESTIGADORES
BERGUER Paula Mercedes
congresos y reuniones científicas
Título:
Omp19 has the ability to induce the internalization of the co-administered antigen in antigen presenting cells in vitro and triggers cytotoxic T cell responses against the antigen.
Autor/es:
L CORIA, A IBÁÑEZ, P BERGUER, P BARRIONUEVO, G GIAMBARTALOMEI, J CASSATARO
Lugar:
Buenos Aires, Argentina
Reunión:
Congreso; 1º Congreso Franco Argentino de Inmunología (FAIC); 2010
Resumen:
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Previously, we have
demonstrated that the protein moiety of Omp19
from Brucella spp.(U-Omp19) has
adjuvant properties and could be used as a Th1 adjuvant that facilitates antigen (Ag) cross-presentation and
induces IFN-γ producing CD8+ T
cells. Given the capacity of antigen
presenting cells (APCs) to modulate immune responses, in the present study we
investigated if APCs are involved in the ability of U-Omp19 to stimulate a
specific CD8 T cell response. To assess this, purified dendritic cells (DCs) from
spleen of C57BL/6 mice were treated with ovoalbumin (OVA) alone or plus U-Omp19
or LPS as positive control and then co-cultivated with OTI CD8+ T cells. We
evaluated the induction
of IFN-γ producing T cells by intracellular
IFN-γ staining and degranulation
of cytotoxic T cells by CD107a expression on the membrane. A higher percentage of IFN-γ producing T CD8 (32.36%)
and cytotoxic T cells (14.06%) was induced when DCs were stimulated with OVA+U-Omp19
compared to T cells co-cultivated with DCs pulsed with OVA alone (23.42% and
8.98% respectively). These results suggested that U-Omp19 can act directly on
DCs to enhance T cell responses. Therefore, we evaluated if Omp19 has a direct
effect on APCs that could
enhance the Ag internalization and presentation to T cells. To this end, purified
DCs from spleen mice were pulsed in vitro
with OVA-FITC alone or OVA-FITC+U-Omp19 or LPS as positive control. DCs pulsed with
OVA-FITC+U-Omp19 showed a greatly increase in Ag internalization compared with
OVA alone (MFI 367.88±19.1 vs. 15.29±1.8). We have also found that U-Omp19
increased OVA internalization by J774 macrophage cell line and by A20J B-lymphoma cell line at different times. These results indicate
that U-Omp19 increases the Ag capture by immature DCs, macrophages and B lymphocytes.
In conclusion, U-Omp19 as adjuvant
increases the amount of internalized Ag in APCs. This capacity would
lead the improved T CD8 and CTL immune
responses observed when U-Omp19 is co-administered with the Ag.