![Figure 1. Both lymphatic and vascular endothelial cells express CLEVER-1. Immunohistologic stainings of (A) normal and (B) inflamed skin (psoriasis). CLEVER-1 is constitutively expressed in the lymphatic endothelial cells (some pointed out by thin black arrows) but induced in vascular HEV-like vessels (thicker white arrows) only in inflammation. Bar, 50 μm. (C-E) Confocal microscopy shows that lymphatic vessels in normal skin are CLEVER-1 positive (C, CLEVER-1 in red; D, LYVE-1 in green; E, merged image), whereas CLEVER-1 is absent from blood vessels (F, CLEVER-1 in green; G, PAL-E in red; H, merged image, no double-positive vessels). In the inflamed psoriatic skin, lymphatic vessels retain CLEVER-1 expression (I, CLEVER-1 in red; J, LYVE-1 in green; K, merged image). In inflammation, CLEVER-1 is induced also in blood vessels (HEV-like venule coexpresses CLEVER-1 [green, L] and PAL-E [red, M] as seen by the yellow signal in the merged image [N]; 0.3-μm optical sections). Representative negative control stainings are shown in the inserts. Bars, 20 μm. (O) An immunofluorescent image of permeabilized HDMECs shows that they are a mixed population of endothelial cells consisting of islets of vascular (CD44+, green) and lymphatic (CD44-, no green fluorescence) endothelial cells. Both types of endothelial cells are CLEVER-1 positive (red, mainly intracellular staining of fine granules/vesicles). Bar, 20 μm. A5× higher magnification of the area highlighted in the schematic picture is shown on the right. BEC indicates blood endothelial cells; LEC, lymphatic endothelial cells. (P) Surface stainings of immunomagnetically separated vascular and lymphatic endothelial cells, spontaneously enriched lymphatic cells, and HUVECs are shown for the indicated antigens. In the bottom line, gray histograms show staining with the negative control mAb 3G6 and black histograms, with anti-CLEVER-1 mAb 3-372. The mean fluorescence intensities of negative control and CLEVER-1 histograms are depicted in the upper right corner (neg.co/CLEVER-1). (Q) Lymphatic endothelial cells isolated from HDMECs based on the absence of CD44 (see P), and HUVECs were immunofluorescently stained for the expression of an established lymphatic marker, podoplanin.](https://ash.silverchair-cdn.com/ash/content_public/journal/blood/104/13/10.1182_blood-2004-01-0222/6/zh80240471020001.jpeg?Expires=1735508134&Signature=OVI~f5cjRexiZSaJUR~rRlePFyMUTzbLXD5qn8wnj-VtwK2HAGgo0puy6pWuRBw7nuHRgjHkaIeiBX1GSq2CsCQkgnYrUeTz-VmtuXXo5VaN1HWwlXZ2jOwRosKrEc~ofxHFRTwyhcK9u8PZ-wwkraxreUaiiA~dGDxk3xwqEA5d-~6hf0np1SN1yeZRzx9fTxwgvOca1qQtsHqlMpJWaLDQoQlPdTliktkX8mcW3hxCnQ1wMBkhl0UqA-xIm3deaoC7Nzm2CWoQptGWbnuI0O5uc8aqj84Ub18b69TCnxSGZbWcfcvK6bN4OwmGzE1qQf7GoZl5AaL6d~KEk4pilw__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
Both lymphatic and vascular endothelial cells express CLEVER-1. Immunohistologic stainings of (A) normal and (B) inflamed skin (psoriasis). CLEVER-1 is constitutively expressed in the lymphatic endothelial cells (some pointed out by thin black arrows) but induced in vascular HEV-like vessels (thicker white arrows) only in inflammation. Bar, 50 μm. (C-E) Confocal microscopy shows that lymphatic vessels in normal skin are CLEVER-1 positive (C, CLEVER-1 in red; D, LYVE-1 in green; E, merged image), whereas CLEVER-1 is absent from blood vessels (F, CLEVER-1 in green; G, PAL-E in red; H, merged image, no double-positive vessels). In the inflamed psoriatic skin, lymphatic vessels retain CLEVER-1 expression (I, CLEVER-1 in red; J, LYVE-1 in green; K, merged image). In inflammation, CLEVER-1 is induced also in blood vessels (HEV-like venule coexpresses CLEVER-1 [green, L] and PAL-E [red, M] as seen by the yellow signal in the merged image [N]; 0.3-μm optical sections). Representative negative control stainings are shown in the inserts. Bars, 20 μm. (O) An immunofluorescent image of permeabilized HDMECs shows that they are a mixed population of endothelial cells consisting of islets of vascular (CD44+, green) and lymphatic (CD44-, no green fluorescence) endothelial cells. Both types of endothelial cells are CLEVER-1 positive (red, mainly intracellular staining of fine granules/vesicles). Bar, 20 μm. A5× higher magnification of the area highlighted in the schematic picture is shown on the right. BEC indicates blood endothelial cells; LEC, lymphatic endothelial cells. (P) Surface stainings of immunomagnetically separated vascular and lymphatic endothelial cells, spontaneously enriched lymphatic cells, and HUVECs are shown for the indicated antigens. In the bottom line, gray histograms show staining with the negative control mAb 3G6 and black histograms, with anti-CLEVER-1 mAb 3-372. The mean fluorescence intensities of negative control and CLEVER-1 histograms are depicted in the upper right corner (neg.co/CLEVER-1). (Q) Lymphatic endothelial cells isolated from HDMECs based on the absence of CD44 (see P), and HUVECs were immunofluorescently stained for the expression of an established lymphatic marker, podoplanin.
