Fig. 4

MCAM-laminin α4 interactions mediate lymphocyte transmigration across human endothelial and fibroblastic layers. a Immunofluorescence staining of cultured fibroblasts derived from primary human choroid plexus cells (HCPEpiC) with anti-laminin α4 (green); cell nuclei are counterstained with DAPI (blue). Bar is 50 μm. b In vitro transmigration of CD4⁺ lymphocytes through the fibroblastic plus connective tissue layer in a modified Boyden chamber assay. Shown are the percentages of MCAM⁺ CD4⁺ T cells before inclusion in the transmigration assay (ex vivo) and after transmigration without (w/o) blocking antibody or with VLA4, MCAM, or MCAM and VLA4 blocking antibodies. Data are from four independent experiments. c Percentages of MCAM⁺ CD4⁺ T cells retained in the HCPEpiC layer in the absence (w/o) or presence of MCAM blocking antibody compared to the original sample (ex vivo). Data are from four independent experiments. d Percentages of MCAM⁺ CD4⁺ T cells before and after transmigration of a HBMEC layer without (w/o) blocking antibody or with MCAM blocking antibody, under non-inflamed or inflammatory conditions (+TNFα). Data are from three independent experiments. e Laminin α4 (green) staining of human choroid plexus tissue from MS CNS samples. Nuclear staining (DAPI) is shown in blue, and the epithelial cell marker cytokeratin 18 (CK18) is shown in red. Bar is 50 μm