Figure 6.

Conduit Flow and Antigen Uptake in Inflamed LNs

Mice were immunized by the subcutaneous injection of IFA/OVA on the right flank. Five days later, fluorescently labeled 10 kDa dextran was injected on both flanks.

(A) Immunofluorescence of 20-μm-thick cryosections of naive and inflamed draining LNs 30 min post-dextran injection. Maximum z stack projections. Scale bars, 40 μm. Graph shows the percentage of dextran⁺ areas within the PDPN⁺ network. Each dot represents a different region of interest. Regions of interest are collated from 6 individual mice per group. Error bars represent means and SDs. ^∗∗∗∗p < 0.0001, unpaired t test.

(B) Immunofluorescence of 20-μm-thick cryosections of naive and inflamed draining LNs 30 min post-dextran injection. Maximum z stack projections. Scale bars, 20 μm. The asterisk indicates a portion of the FRC network with all conduit components plus dextran flow. The arrowhead indicates a portion of the FRC network in which the conduit is not present and dextrans are not flowing.

(C) Percentage of dextran⁺ cells as quantified by flow cytometry 90 min after dextran injection. Error bars represent means and SDs.

(D) The number of dextran⁺ cells per LN (i); the number of MHCII⁺ dextran⁺ cells (ii); the number of dextran⁺ cells within myeloid subsets (iii). Each dot represents an individual mouse (n = 6). Error bars represent means and SDs.

(E) Representative images of CD11b⁺ myeloid cells in cryosections of the fibroblastic reticular network. Scale bars, 20 μm.

(F) Quantification of the percentage (left) and the number (right) of CD11b⁺ myeloid cells interacting with conduit structures from regions of interest from 5 biological replicates. Error bars represent means and SDs.