PA-IIL  (Synonyms: LecB)

PA-IIL (LecB) is a lectin produced by Pseudomonas aeruginosa. PA-IIL binds to glycosylated β1-integrin, fucose-containing glycosphingolipids, fucosylated/mannosylated neutrophil glycoconjugates, and pre-formed neutrophil extracellular traps. PA-IIL disrupts host defenses: it creates favorable conditions for Pseudomonas aeruginosa infection and dissemination by modulating the bactericidal activity of neutrophils, impairing the trafficking and recruitment of immune cells, and compromising the repair capacity of epithelial barriers. PA-IIL can be used in studies related to Pseudomonas aeruginosa infection^[1][2][3][4].

PA-IIL (50 μg/mL; 6-12 h) disrupts epithelial polarity and tight junction integrity in MDCK cells when applied basolaterally, whereas apical application has no such effects^[1].
PA-IIL (50 μg/mL; 1-6 h + 5-20 h washout recovery) causes rapid internalization of β1-integrins in MDCK cells when applied basolaterally, and this effect is reversible upon LecB washout, with integrin surface localization and TEER recovering over time^[1].
PA-IIL specifically binds to glycosylated β1-integrins at the basolateral surface of MDCK cells, with strong binding affinity capable of extracting 75% of total β1-integrin^[1].
PA-IIL (50 μg/mL; 10 min-6 h) causes internalization and lysosomal degradation of α3β1-integrin-laminin complexes in MDCK cells when applied basolaterally, regardless of β1-integrin activation status^[1].
PA-IIL induces membrane invaginations by binding fucose-bearing glycosphingolipids, and cross-links these invaginated membrane regions with β1-integrins in MDCK cells, providing a mechanism for integrin internalization^[1].
PA-IIL (5-100 μg/mL; 3-22 h) inhibits epithelial wound healing in MDCK cells in vitro in a dose-dependent manner, with concentrations greater than 50 μg/mL completely blocking migration, by inducing β1-integrin internalization in wound edge cells and preventing lamellipodium formation^[1].
PA-IIL (5 μM; 3 days) inhibits emigration of dermal CD14⁺ DCs, dermal CD14^- DCs, and epidermal Langerhans cells from human skin explants, and reduces CD18/ITGb2-CD11c/ITGb2 heterodimer expression on dermal DCs^[3].
PA-IIL (1 μg/mL; 2 h) binds to ex vivo isolated human blood and lymphatic endothelial cells^[3].
PA-IIL (5 μg/mL; 17 h) impairs transmigration of human PBMCs, lymphocytes, and monocytes across a human CMEC/D3 endothelial monolayer, increases leukocyte adherence to the monolayer, and disrupts VE-cadherin localization at endothelial cell membranes^[3].
PA-IIL (5 μg/mL; 1-5 h) induces time-dependent endocytosis and degradation of VE-cadherin, reorganization of the F-actin cytoskeleton, displacement of FAK, reduced myosin regulatory light chain phosphorylation, and arrested motility in human HUVECs, without causing cytotoxicity^[3].
PA-IIL (0.015-3 μM) induces intracellular reactive oxygen species production in LPS-primed and TNFα-primed human neutrophils (but not unprimed or 37°C-primed neutrophils) in a concentration-dependent manner, with significant activity at 1.5 μM and above^[4].
PA-IIL (0.015-3 μM; 30 min on ice) binds equally to the surface of unprimed, 37°C-primed, LPS-primed, and TNFα-primed human neutrophils, with binding increasing in a concentration-dependent manner, and binding is completely inhibited by methyl fucoside^[4].
PA-IIL (1.5 μM) inhibits phagocytosis-induced intracellular reactive oxygen species production in unprimed human neutrophils exposed to serum-opsonized Pseudomonas aeruginosa or Staphylococcus aureus^[4].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

PA-IIL (12.5 µg; i.d., i.fp.; 2 doses 18 hours apart, single dose) binds to lymphatic and blood endothelial cells in mouse skin and lymph nodes, inhibits dendritic cell migration from skin to lymph node CD4⁺ T cell zones, and reduces antigen-specific CD4⁺ T cell proliferation, with these effects reversible by a LecB inhibitor^[3].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

[PA-IIL]

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Please store the product under the recommended conditions in the Certificate of Analysis.

• [1]. Thuenauer R, et al. The Pseudomonas aeruginosa Lectin LecB Causes Integrin Internalization and Inhibits Epithelial Wound Healing. mBio. 2020;11(2):e03260-19. Published 2020 Mar 10.

  [2]. Csávás M, et al. A fucosylated lactose-presenting tetravalent glycocluster acting as a mutual ligand of Pseudomonas aeruginosa lectins A (PA-il) and B (PA-iil)—synthesis and interaction studies. International Journal of Molecular Sciences. 2022 Dec 19;23(24):16194.
  

  [3]. Sponsel J, et al. Pseudomonas aeruginosa LecB suppresses immune responses by inhibiting transendothelial migration. EMBO Rep. 2023;24(4):e55971.

  [4]. Sanchez Klose FP, et al. The Pseudomonas aeruginosa lectin LecB modulates intracellular reactive oxygen species production in human neutrophils. Eur J Immunol. 2024;54(2):e2350623.