TY - JOUR
T1 - Phenotype-associated lectin-binding profiles of normal and transformed blood cells
T2 - A comparative analysis of mannose- and galactose-binding lectins from plants and human serum/placenta
AU - Mann, K. K.
AU - Andre, S.
AU - Gabius, H. J.
AU - Sharp, J. G.
PY - 1994
Y1 - 1994
N2 - Surface glycoconjugates of normal and transformed blood cells are commonly characterized by plant lectins. To infer physiological significance of protein-carbohydrate interactions, mammalian lectins are obviously preferable as research tools. So far, human serum lectins have not been used to assess their binding to immunophenotyped human normal or transformed blood cells. Thus, our study combines two groups of lectins with different specificity from plant and human sources. Besides concanavalin A (ConA) we have isolated the mannose-binding protein and serum amyloid P component from human serum. Especially the mannose-binding protein is believed to play a role in host defence against bacteria and yeast cells with unknown impact on normal and tumor cells. These three lectins establish the first group. In addition to the immunomodulatory mistletoe lectin, whose binding can elicit enhanced cytokine secretion from mononuclear blood cells, we included the β-galactoside-binding lectin (14 kDa) from human placenta in the second group. The initial series of measurements was undertaken using two-color flow cytometry to determine the phenotype-associated binding (based on cluster designation; CD) of the lectins to blood and bone marrow cells from normal donors and the cell line CEM (T-lymphoblastoid), KG1-A (primitive myeloid leukemia) and Croco II (B-lymphoblastoid). Heterogeneity was apparent for each lectin in the CD-defined cell populations. Significant differences in binding were noted between Viscum album agglutinin (VAA) and other lectins for CD4+ cells from blood and between mannose-binding protein (MBP) and VAA versus 14 kDa, ConA and serum amyloid P component (SAP) for CD19° cells from bone marrow. Generally, the binding of lectins to the cultured cells, as determined by flow cytometry, was lower than to cells of the corresponding CD phenotype in blood or bone marrow. The exception was VAA binding, which was rather similar on normal and cultured cells. Quantitative differences in binding between human and plant lectins of the same monosaccharide specificity were noted, as also seen in analysis of binding data with increasing concentrations of lectins for Croco II cells. As further parameter to estimate the extent of cell binding of lectins, a cell adhesion assay was performed. When these cells were used in an in vitro adhesion assay on matrix-immobilized lectins, cell adhesion, blocked by carbohydrate ligands, was mainly seen with the plant lectins. Under identical conditions the lectins from the homologous source failed to mediate strong adhesion despite measurable extent of binding. The further characterization of the detected binding to blood cells will provide insights into functional aspects of these endogenous lectins.
AB - Surface glycoconjugates of normal and transformed blood cells are commonly characterized by plant lectins. To infer physiological significance of protein-carbohydrate interactions, mammalian lectins are obviously preferable as research tools. So far, human serum lectins have not been used to assess their binding to immunophenotyped human normal or transformed blood cells. Thus, our study combines two groups of lectins with different specificity from plant and human sources. Besides concanavalin A (ConA) we have isolated the mannose-binding protein and serum amyloid P component from human serum. Especially the mannose-binding protein is believed to play a role in host defence against bacteria and yeast cells with unknown impact on normal and tumor cells. These three lectins establish the first group. In addition to the immunomodulatory mistletoe lectin, whose binding can elicit enhanced cytokine secretion from mononuclear blood cells, we included the β-galactoside-binding lectin (14 kDa) from human placenta in the second group. The initial series of measurements was undertaken using two-color flow cytometry to determine the phenotype-associated binding (based on cluster designation; CD) of the lectins to blood and bone marrow cells from normal donors and the cell line CEM (T-lymphoblastoid), KG1-A (primitive myeloid leukemia) and Croco II (B-lymphoblastoid). Heterogeneity was apparent for each lectin in the CD-defined cell populations. Significant differences in binding were noted between Viscum album agglutinin (VAA) and other lectins for CD4+ cells from blood and between mannose-binding protein (MBP) and VAA versus 14 kDa, ConA and serum amyloid P component (SAP) for CD19° cells from bone marrow. Generally, the binding of lectins to the cultured cells, as determined by flow cytometry, was lower than to cells of the corresponding CD phenotype in blood or bone marrow. The exception was VAA binding, which was rather similar on normal and cultured cells. Quantitative differences in binding between human and plant lectins of the same monosaccharide specificity were noted, as also seen in analysis of binding data with increasing concentrations of lectins for Croco II cells. As further parameter to estimate the extent of cell binding of lectins, a cell adhesion assay was performed. When these cells were used in an in vitro adhesion assay on matrix-immobilized lectins, cell adhesion, blocked by carbohydrate ligands, was mainly seen with the plant lectins. Under identical conditions the lectins from the homologous source failed to mediate strong adhesion despite measurable extent of binding. The further characterization of the detected binding to blood cells will provide insights into functional aspects of these endogenous lectins.
KW - Adhesion
KW - Blood cells
KW - Glycoconjugate
KW - Lectin
KW - Leukemia
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M3 - Article
C2 - 7889985
AN - SCOPUS:0028075763
SN - 0171-9335
VL - 65
SP - 145
EP - 151
JO - European Journal of Cell Biology
JF - European Journal of Cell Biology
IS - 1
ER -