Figure 3
CCR7−/− mice show increased regulatory T cells (Tregs) within isolated lymphoid follicles and enhanced colonic antigen-specific immunoglobulin (Ig)G and IgM serum levels. (a) Paraffin-embedded sections of the large intestine of 8–12-week-old Wt or CCR7−/− mice (n=6–7 per group) were immunohistochemically stained for Treg cells (Foxp3 in red) and B cells (B220 in blue). Representative sections are shown. Enlarged magnification of representative areas in the insets. Bar=100 μm. (b) Arithmetic means of the absolute lamina propria (LP) Foxp3+ Treg cells of wild-type (Wt) (black bars; n=4) and CCR7−/− (open bars; n=6) mice. Data were calculated from flow cytometry analysis of CD4+, CD25+, and Foxp3+ expression by size-gated LP cells. *P<0.05; Mann–Whitney test. Relative serum (c) IgG and (d) IgM (left panel) autoantibody titers directed against colonic-derived antigen of 8–12-week-old Wt (black bars) and CCR7−/− (open bars) mice. Sera were used at a dilution of 1:50. Absorbance values at 450 nm represent the relative anti-colonic IgG or IgM. Bars represent means±s.d.; ***P<0.001, Mann–Whitney test. (d, right panel) Serum of CCR7−/− (n=5) but not of Wt mice (n=5) reacted with enterocytes in cryosections of the large intestine analyzed by immunofluorescence staining. For immunofluorescence stainings, cryosections were incubated with mouse serum diluted 1:50. Binding of circulating IgM to the tissue was detected with rat anti-mouse IgM antibody (red). Representative sections are shown.
