Abstract
The parameters of the reaction between a rat alveolar macrophage lectin (Mr = 180,000) and its ligands have been examined. The reaction is dependent on Ca2+ over the optimal pH range for binding. The apparent dissociation constant for fucosyl bovine serum albumin, the standard ligand used in these studies, is 1.4 X 10(-10) M. The ligand binding specificity was determined by measurement of the inhibition of binding of fucosyl bovine serum albumin by various glycoproteins and saccharides. D-Mannose, L-fucose, and N-acetyl-D-glucosamine were the most effective inhibitors, and D-galactose was much poorer. The equatorial hydroxyl groups on the C-3 and C-4 of the mannose ring are important in the lectin-ligand interaction, and the axial hydroxyl group on the C-2 contributes to a lesser extent. Immunocytological studies revealed that the lectin isolated from alveolar macrophages is widely distributed in other rat tissues. Hepatocytes are devoid of the lectin, but hepatic Kupffer cells and endothelial cells contain significant amounts. This was confirmed by isolation of the lectin from liver. Spleen and skeletal muscle also contain lectin, but much smaller amounts were found in brain, kidney, and heart muscle.
Highlights
The parameters of thereaction between a rat alveo- affinityformannoseand fucose, a lesser affinityfor N - lar macrophage lectin (Mr= 180,000) and its ligands acetylglucosamine, and binds neithergalactose nor N-acetylhave been examined
The apparent We report here further studies on the bindingof the lectin dissociation constant for fucosyl bovine serum albu- toits ligands,including its ligand binding specificity
The equatorial hydroxyl groups on the C-3 and C - 4 of the mannose ring are important in the lectin-ligand interaction, and the axial hydroxyl group on the C-2 contributes to a lesser extent
Summary
Materials-Rat alveolar macrophage lectin (ll),rat Kupffer cell lectin Goat antirabbit Fc fragment specific IgG and goat anti-rabbit IgG (Cappel) labeled with fluorescein isothiocyanate [16] were kindly provided by isolated from alveolar macrophages is widely distrib- Dr M The fixed thin section was rinsed with buffer A (10 mM sodium phosphate, pH 7.4, containing 0.15 M sodium chloride, and 0.02% sodium azide) and thenincubated for 2 h a t 25 “C with 50 pl of buffer A containing 1%BSA and 100 and greably diminished below pH 6 It hasa high pg/ml immune or preimmune anti-alveolar macrophage lectin IgG.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.