Figure 5
Enhanced activation of specific mesenteric lymph nodes (MLN) CD4+ T cells by immunoglobulin A–dependent intestinal transport of ovalbumin (OVA). (a) Flow cytometry analysis of CD69 expression by OVA-specific (KJ1-26+) CD4+ T cells and (b) enzyme-linked immunosorbent assay determination of interferon (IFN)-γ secretion after a 72-h stimulation by OVA in MLN from DO11.10 transgenic mice daily gavaged with bicarbonate buffer (Control) or with 25 mg OVA for 4 days (OVA gav) and bearing or not an OVA- or β-lactoglobulin backpack (BP) and treated or not with tyrphostin A8 (TyrA8). CD69 expression is shown for the various groups as histograms with medians and ranges (b, left panel). Flow cytometry analysis of one representative experiment out of four shows the percentage of CD69+ among CD3+CD4+T cells expressing (light grey) or not expressing (dark grey) the OVA-specific T-cell receptor (TCR; a, right panel). Control and OVA gav groups: n=7 and 5 in panels a and b, respectively; OVA gav+TyrA8 group: n=5 and 5; OVA gav+OVA-BP group: n=10 and 10; OVA gav+OVA-BP+TyrA8 group: n=11 and 10; OVA gav+β-lacto-BP+TyrA8 group: n=7 and 5. *Significantly different from the control group, P<0.01 in a, P<0.03 in b. #Significantly different from the OVA gav+OVA-BP+TyrA8 group, P<0.01 in panel a, P<0.03 in panel b.
