Figure 5.

β7 sufficient bone marrow derived cells are essential for the formation of ILFs. Lethally irradiated C57BL/6 congenic (IgM^a, CD90.1) mice were given bone marrow from gender-matched β7−/− (IgM^b, CD90.2) or C57BL/6 (IgM^b, CD90.2) donors and examined for the presence of donor lymphocytes in the spleen, intestinal CD90 clusters, and intestinal B220 clusters. Flow cytometric analysis of splenocytes demonstrated effective engraftment of donor B-lymphocytes (IgM^b+) and T-lymphocytes (CD90.2+), and the absence of β7 expression in splenocytes from recipients of β7−/− bone marrow (panels A and B). There were no differences in the infiltration of the CD90+ clusters with CD11c+ cells (panels E and H). Few CD90+ clusters from recipients receiving β7−/− mice bone marrow contained B-lymphocytes (panels C,D,F, and G), and quantitatively this was associated with a significant decrease in the number of B220+ clusters in these recipients (panel H). All CD90 clusters in both groups contained a population of CD90.1+ (recipient derived, wildtype) CP cells. However the CD90+ clusters in the recipients of β7−/− bone marrow contained few CD90.2+ (donor derived) CP cells (compare panels C and F), suggesting a relative defect in the ability of these cells to localize to the CP in the absence of β7. Data in panel I is presented as the mean ± the standard error of the mean of data generated from 3 mice in each group. The scale bar in panel C = 100µm. * = p<0.05.