Fig. 3.

Soluble Ig is sufficient to restore efficient cross-presentation by cDCs from lymphopenic mice. (A) Splenic cDCs from WT, RAG^−/−, mb1^cre/cre, and mb1^cre/+ mice were loaded with OVA (500 μg/mL) and incubated with CFSE-labeled OT I cells for 2 d. (B) WT and RAG^−/− mice were i.v. injected with splenic WT T cells (CD3⁺CD4⁺ and CD3⁺CD8⁺). Three weeks after T-cell transfer, splenic DCs were sorted from recipient mice, loaded with OVA (500 μg/mL), and incubated with CFSE-labeled OT I cells for 2 d. (C) Splenic cDCs isolated from WT, RAG^−/−, or RAG2^−/−γc^−/− were loaded with OVA (500 μg/mL) and incubated with CFSE-labeled OT I cells for 2 d. (D) WT and RAG^−/− mice were injected three times within 21 d i.v. with serum collected from WT and RAG^−/− mice. (E) WT and RAG^−/− mice were injected twice within 21 d i.v. with murine IgG (7.5 μg per mouse) and/or murine IgM (7.5 μg per mouse). The proliferative response of T cells was enumerated by flow cytometry. Numbers of proliferating cells are shown (mean + SEM). Data are representative of two or three independent experiments with minimum three mice per group. Statistical significance was determined by using paired Student’s t test. *P < 0.05; **P < 0.01; ***P < 0.005. n.s., not significant.