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A novel endothelial L-selectin ligand activity in lymph node medulla that is regulated by alpha(1,3)-fucosyltransferase-IV.

M'Rini C, Cheng G, Schweitzer C, Cavanagh LL, Palframan RT, Mempel TR, Warnock RA, Lowe JB, Quackenbush EJ, von Andrian UH - J. Exp. Med. (2003)

Bottom Line: The relative mRNA level of FucT-IV was higher in medullary venules than in HEVs, whereas FucT-VII was most prominent in HEVs and weak in medullary venules.Thus, two distinct L-selectin ligands are segmentally confined to contiguous microvascular domains in PLNs.Although MECA-79-reactive species predominate in HEVs, medullary venules express another ligand that is spatially, antigenically, and biosynthetically unique.

View Article: PubMed Central - PubMed

Affiliation: CBR Institute for Biomedical Research, Harvard Medical School, Boston, MA 02115, USA.

ABSTRACT
Lymphocytes home to peripheral lymph nodes (PLNs) via high endothelial venules (HEVs) in the subcortex and incrementally larger collecting venules in the medulla. HEVs express ligands for L-selectin, which mediates lymphocyte rolling. L-selectin counterreceptors in HEVs are recognized by mAb MECA-79, a surrogate marker for molecularly heterogeneous glycans termed peripheral node addressin. By contrast, we find that medullary venules express L-selectin ligands not recognized by MECA-79. Both L-selectin ligands must be fucosylated by alpha(1,3)-fucosyltransferase (FucT)-IV or FucT-VII as rolling is absent in FucT-IV+VII(-/-) mice. Intravital microscopy experiments revealed that MECA-79-reactive ligands depend primarily on FucT-VII, whereas MECA-79-independent medullary L-selectin ligands are regulated by FucT-IV. Expression levels of both enzymes paralleled these anatomical distinctions. The relative mRNA level of FucT-IV was higher in medullary venules than in HEVs, whereas FucT-VII was most prominent in HEVs and weak in medullary venules. Thus, two distinct L-selectin ligands are segmentally confined to contiguous microvascular domains in PLNs. Although MECA-79-reactive species predominate in HEVs, medullary venules express another ligand that is spatially, antigenically, and biosynthetically unique. Physiologic relevance for this novel activity in medullary microvessels is suggested by the finding that L-selectin-dependent T cell homing to PLNs was partly insensitive to MECA-79 inhibition.

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Fluorescent bead accumulation in PLNs reveals segmental differences in luminal antigen expression between venular branching orders. Binding of nonspecific mAb-coated NR and specific mAb-coated YG fluorescent beads in PLN microvessels 15 min after i.v. injection. NR beads were injected first, followed by an equivalent number of YG beads coated with mAb MECA-79, anti-sLeX/A (HECA-452), anti–ICAM-1, or anti–ICAM-2. The accumulation of specific beads was calculated as described in Materials and Methods. All specific mAb-coated beads bound significantly more than control beads, except for MECA-79–coated beads in order I venules, and both MECA-79 and anti-sLeX/A–coated beads in arterioles. *, P < 0.05; **, P < 0.01; ***, P < 0.001 compared with order I venules. Number of LNs/venules analyzed: 9/54 for ICAM-1; 3/46 for ICAM-2; 5/77 for sLeX/A; and 4/45 for MECA-79.
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fig3: Fluorescent bead accumulation in PLNs reveals segmental differences in luminal antigen expression between venular branching orders. Binding of nonspecific mAb-coated NR and specific mAb-coated YG fluorescent beads in PLN microvessels 15 min after i.v. injection. NR beads were injected first, followed by an equivalent number of YG beads coated with mAb MECA-79, anti-sLeX/A (HECA-452), anti–ICAM-1, or anti–ICAM-2. The accumulation of specific beads was calculated as described in Materials and Methods. All specific mAb-coated beads bound significantly more than control beads, except for MECA-79–coated beads in order I venules, and both MECA-79 and anti-sLeX/A–coated beads in arterioles. *, P < 0.05; **, P < 0.01; ***, P < 0.001 compared with order I venules. Number of LNs/venules analyzed: 9/54 for ICAM-1; 3/46 for ICAM-2; 5/77 for sLeX/A; and 4/45 for MECA-79.

Mentions: The rolling behavior of L1-2L-selectin cells together with the CFSE-MECA-79 staining pattern suggested the existence of MECA-79–insensitive L-selectin ligand(s) in LOVs. To eliminate the possibility of a low density MECA-79–reactive ligand that was undetectable using video microscopy, we established a more sensitive, semiquantitative assay to analyze luminal surface antigens in PLNs. Polystyrene beads (1 μm diameter) emitting either YG or NR fluorescence were coated with mAbs against endothelial adhesion molecules or control mAbs, respectively. Equivalent numbers of beads were successively injected into mice and branching order-specific bead accumulation was determined in PLNs (Fig. 3) .


A novel endothelial L-selectin ligand activity in lymph node medulla that is regulated by alpha(1,3)-fucosyltransferase-IV.

M'Rini C, Cheng G, Schweitzer C, Cavanagh LL, Palframan RT, Mempel TR, Warnock RA, Lowe JB, Quackenbush EJ, von Andrian UH - J. Exp. Med. (2003)

Fluorescent bead accumulation in PLNs reveals segmental differences in luminal antigen expression between venular branching orders. Binding of nonspecific mAb-coated NR and specific mAb-coated YG fluorescent beads in PLN microvessels 15 min after i.v. injection. NR beads were injected first, followed by an equivalent number of YG beads coated with mAb MECA-79, anti-sLeX/A (HECA-452), anti–ICAM-1, or anti–ICAM-2. The accumulation of specific beads was calculated as described in Materials and Methods. All specific mAb-coated beads bound significantly more than control beads, except for MECA-79–coated beads in order I venules, and both MECA-79 and anti-sLeX/A–coated beads in arterioles. *, P < 0.05; **, P < 0.01; ***, P < 0.001 compared with order I venules. Number of LNs/venules analyzed: 9/54 for ICAM-1; 3/46 for ICAM-2; 5/77 for sLeX/A; and 4/45 for MECA-79.
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2194247&req=5

fig3: Fluorescent bead accumulation in PLNs reveals segmental differences in luminal antigen expression between venular branching orders. Binding of nonspecific mAb-coated NR and specific mAb-coated YG fluorescent beads in PLN microvessels 15 min after i.v. injection. NR beads were injected first, followed by an equivalent number of YG beads coated with mAb MECA-79, anti-sLeX/A (HECA-452), anti–ICAM-1, or anti–ICAM-2. The accumulation of specific beads was calculated as described in Materials and Methods. All specific mAb-coated beads bound significantly more than control beads, except for MECA-79–coated beads in order I venules, and both MECA-79 and anti-sLeX/A–coated beads in arterioles. *, P < 0.05; **, P < 0.01; ***, P < 0.001 compared with order I venules. Number of LNs/venules analyzed: 9/54 for ICAM-1; 3/46 for ICAM-2; 5/77 for sLeX/A; and 4/45 for MECA-79.
Mentions: The rolling behavior of L1-2L-selectin cells together with the CFSE-MECA-79 staining pattern suggested the existence of MECA-79–insensitive L-selectin ligand(s) in LOVs. To eliminate the possibility of a low density MECA-79–reactive ligand that was undetectable using video microscopy, we established a more sensitive, semiquantitative assay to analyze luminal surface antigens in PLNs. Polystyrene beads (1 μm diameter) emitting either YG or NR fluorescence were coated with mAbs against endothelial adhesion molecules or control mAbs, respectively. Equivalent numbers of beads were successively injected into mice and branching order-specific bead accumulation was determined in PLNs (Fig. 3) .

Bottom Line: The relative mRNA level of FucT-IV was higher in medullary venules than in HEVs, whereas FucT-VII was most prominent in HEVs and weak in medullary venules.Thus, two distinct L-selectin ligands are segmentally confined to contiguous microvascular domains in PLNs.Although MECA-79-reactive species predominate in HEVs, medullary venules express another ligand that is spatially, antigenically, and biosynthetically unique.

View Article: PubMed Central - PubMed

Affiliation: CBR Institute for Biomedical Research, Harvard Medical School, Boston, MA 02115, USA.

ABSTRACT
Lymphocytes home to peripheral lymph nodes (PLNs) via high endothelial venules (HEVs) in the subcortex and incrementally larger collecting venules in the medulla. HEVs express ligands for L-selectin, which mediates lymphocyte rolling. L-selectin counterreceptors in HEVs are recognized by mAb MECA-79, a surrogate marker for molecularly heterogeneous glycans termed peripheral node addressin. By contrast, we find that medullary venules express L-selectin ligands not recognized by MECA-79. Both L-selectin ligands must be fucosylated by alpha(1,3)-fucosyltransferase (FucT)-IV or FucT-VII as rolling is absent in FucT-IV+VII(-/-) mice. Intravital microscopy experiments revealed that MECA-79-reactive ligands depend primarily on FucT-VII, whereas MECA-79-independent medullary L-selectin ligands are regulated by FucT-IV. Expression levels of both enzymes paralleled these anatomical distinctions. The relative mRNA level of FucT-IV was higher in medullary venules than in HEVs, whereas FucT-VII was most prominent in HEVs and weak in medullary venules. Thus, two distinct L-selectin ligands are segmentally confined to contiguous microvascular domains in PLNs. Although MECA-79-reactive species predominate in HEVs, medullary venules express another ligand that is spatially, antigenically, and biosynthetically unique. Physiologic relevance for this novel activity in medullary microvessels is suggested by the finding that L-selectin-dependent T cell homing to PLNs was partly insensitive to MECA-79 inhibition.

Show MeSH
Related in: MedlinePlus