IL-12p40 is produced rapidly and transiently in the spleen by CD8⁺ DC following <i>L. donovani</i> infection.

<p>(A) Mice were infected with 2×10⁷<i>L. donovani</i> amastigotes i.v. and sacrificed at 2 hr, 5 hr, 12 hr, 24 hr, 72 hr, 5 days and 7 days p.i. mRNA was extracted from the spleen (squares), liver (inverted triangles) and bone marrow (triangles) at each time point and accumulation of IL-12p40 mRNA was detected by real-time RT-PCR and is expressed as mRNA molecule per 1000 HPRT molecules. Data are representative of 3 mice per time point. (B) Mice were infected with 1×10⁸<i>L. donovani</i> amastigotes i.v. and spleens were removed at 5 hr p.i. MACS-enriched DC were enumerated by labelling with anti-CD11c mAb and examined for expression of isotype control mAb or IL-12p40 (1,000,000 events collected, 10,000 events shown). Cells were then electronically gated, based on expression of IL-12p40, as indicated, and then examined for expression of CD4 and CD8 (5000 events shown). Gates were determined from an isotype control for IL-12p40, in which 0.8% of CD11c⁺ cells were shown to be positive. Numbers below rectangular gates indicate the percentage of cells in that gate, while numbers in the upper right hand corners of FACS profiles indicate the percentage of cells in the indicated quadrants. One representative experiment of three performed with similar outcome is shown (n = 4 mice per treatment group in each experiment).