Previously, we reported that between 10-15 days after Trypanosoma cruzi infection, Balb/c mice
show in the peritoneal cavity (PC) an increase in the number of plasma cells identified as
CD5low/-CD19low/-CD23low/-Syndecan-1neg and intracellular IgM+ or IgG+. These cells cultured for
48h with medium alone release IgM and high levels of IgG to the cell-culture supernatant. These antibodies are not reactive with T. cruzi antigens. The presence of antibody-secreting cells in the PC correlates with high levels of parasitemia, high number of infiltrating T-cells and cellular debris. In order to analyze possible stimulus able to induce peritoneal B1-cell differentiation, purified B1 cells from PC of normal mice were cultured with F(ab)2anti-u
(10ug/ml, simulating antigen interaction), anti-CD40 (5ug/ml, simulating T-cell interaction), CpG (1ug/ml), LPS (5ug/ml) and different number of T. cruzi trypomastigotes during 72h. The differentiation process was followed by FACS and ELISA. All stimulus otherwise F(ab)2anti-u
induced IgM but only CpG and LPS induced high levels of IgM secretion. High levels of IgG secreted were induced by anti-CD40 or the parasite stimulus but not by anti-u or TLR-ligands tested. The injection of a TLR9-antagonist (ODN 2088) into the PC of T. cruzi infected mice did not affect B1-cell differentiation and antibody secretion. These results suggest that TLR4 but not TLR9 ligands generated during infection would be responsible for the non-specific IgM while the parasite and/or the interaction with T-cells would be responsible for the non-specific IgG levels produced by B1 cells. Futher in vivo blockingexperiments will be performed to verify this conclusion.
48h with medium alone release IgM and high levels of IgG to the cell-culture supernatant.
These antibodies are not reactive with T. cruzi antigens. The presence of antibody-secreting
cells in the PC correlates with high levels of parasitemia, high number of infiltrating T-cells and
cellular debris. In order to analyze possible stimulus able to induce peritoneal B1-cell
differentiation, purified B1 cells from PC of normal mice were cultured with F(ab)2anti-u
(10ug/ml, simulating antigen interaction), anti-CD40 (5ug/ml, simulating T-cell interaction), CpG (1ug/ml), LPS (5ug/ml) and different number of T. cruzi trypomastigotes during 72h. The differentiation process was followed by FACS and ELISA. All stimulus otherwise F(ab)2anti-u
induced IgM but only CpG and LPS induced high levels of IgM secretion. High levels of IgG secreted were induced by anti-CD40 or the parasite stimulus but not by anti-u or TLR-ligands tested. The injection of a TLR9-antagonist (ODN 2088) into the PC of T. cruzi infected mice did not affect B1-cell differentiation and antibody secretion. These results suggest that TLR4 but not TLR9 ligands generated during infection would be responsible for the non-specific IgM while the parasite and/or the interaction with T-cells would be responsible for the non-specific IgG levels produced by B1 cells. Futher in vivo blockingexperiments will be performed to verify this conclusion.
(10ug/ml, simulating antigen interaction), anti-CD40 (5ug/ml, simulating T-cell interaction), CpG
(1ug/ml), LPS (5ug/ml) and different number of T. cruzi trypomastigotes during 72h. The
differentiation process was followed by FACS and ELISA. All stimulus otherwise F(ab)2anti-u
induced IgM but only CpG and LPS induced high levels of IgM secretion. High levels of IgG secreted were induced by anti-CD40 or the parasite stimulus but not by anti-u or TLR-ligands tested. The injection of a TLR9-antagonist (ODN 2088) into the PC of T. cruzi infected mice did not affect B1-cell differentiation and antibody secretion. These results suggest that TLR4 but not TLR9 ligands generated during infection would be responsible for the non-specific IgM while the parasite and/or the interaction with T-cells would be responsible for the non-specific IgG levels produced by B1 cells. Futher in vivo blockingexperiments will be performed to verify this conclusion.
induced IgM but only CpG and LPS induced high levels of IgM secretion. High levels of IgG
secreted were induced by anti-CD40 or the parasite stimulus but not by anti-u or TLR-ligands
tested.
The injection of a TLR9-antagonist (ODN 2088) into the PC of T. cruzi infected mice did not
affect B1-cell differentiation and antibody secretion.
These results suggest that TLR4 but not TLR9 ligands generated during infection would be
responsible for the non-specific IgM while the parasite and/or the interaction with T-cells would
be responsible for the non-specific IgG levels produced by B1 cells. Futher in vivo blockingexperiments
will be performed to verify this conclusion.
