Monoclonal Antibodies against Leucoagglutinin‐Reactive Human T‐Lymphocyte Surface Components (original) (raw)
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European Journal of Immunology, 1987
Immunoprecipitation studies from lZ5I-labeled T cells, previously activated with the lectin phytohemagglutinin (PHA) from Phaseolus vulgaris, showed a preferential association between the CD45 glycoprotein family containing members of 220, 205, 190 and 180 kDa, and a protein of 33 kDa. This 33-kDa protein, with an identical molecular mass as PHA, was not associated with other highly expressed molecules such as class I histocompatibility antigens (HLA-A,B,C), transferrin receptor, CDw44 and CDlla. Further immunoprecipitation analysis from peripheral blood lymphocytes incubated with '251-labeled PHA confirmed the identification of the CD45-associated 33-kDa protein as the lectin PHA. These results prompted us to analyze the possible involvement of the CD45 molecules in the T cell activation process induced by PHA. Thus, two monoclonal antibodies specific for CD45 antigens were able to inhibit the T cell proliferation induced by the lectin. This inhibitory ability was exerted by affecting both the interleukin 2 production and the interleukin 2 receptor expression.
Scandinavian Journal of Immunology, 1976
The relationship between the surface receptors on neuraminidase-treated human blood lymphocytes for the mitogenic lectins Phaseolus vulgaris leukoagglutinin (La), concanavalin A (Con A) and soy bean agglutinin (SBA) and the non-mitogenic lectin Helix pomatia A hemagglutinin (HP) was investigated. Two different techniques, co-capping with different fluorochrome-labeled lectins and cell binding-inhibition experiments with 125I-labeled lectins, were used. The results demonstrated that the nonmitogenic lectin HP and the mitogenic lectins SBA, La and Con A bind either to the same macromolecule (s) or to different but physically linked macromolecules on the surface of human T lymphocytes. In contrast, only part of beta2-microglobulin (beta2-m) or beta2-m-bearing complexes, appear to be physically linked to the lectin receptor complex(es). On the lectin-binding substance(s) at least two saccharide structures were recognized, one of which binds both HP and SBA and another which binds SBA and La (and probably also Con A) but not HP.
European Journal of Immunology, 1977
CML suppression by lectin-activated peripheral blood lymphocytes 11 Suppression of generation of human cytotoxic effectors by lectins or lectin-activated peripheral blood lymphocytes* The lectins phytohemagglutinin, pokeweed mitogen and concanavalin A used at their optimal mitogenic concentration, or human lymphocytes activated by the same mitogens, were found t o suppress the in virro generation of cytotoxic effectors when added to a cell-mediated lympholysis (CML) mixture during the first 48 h of culture. The data suggest that the suppressive mechanism is mediated to a greater extent by an allogeneic interaction between lectin-activated cells and the allogeneic cells present in the CML mixture than by suppressor cells induced by the lectin. Since partial suppression was observed with supernatants of activated lymphocytes cultured for 18 h with allogeneic stimulating cells (but not activated lymphocytes alone), a soluble mediator may be involved in the suppressive mechanism. The mechanism of suppression therefore may be identical to the preemption phenomenon recently described in primary and secondary CML.
Annals of the New York Academy of Sciences, 1988
Human T lymphocytes can be nonspecifically stimulated through the interaction between certain lectins or monoclonal antilymphocyte antibodies (mAbs) and cell surface receptors. Several mAbs directed against the T-cell antigen receptor TCR-CD3 complex and against peptides that have no known role in antigenic recognition (e.g., CD2 and CD28) were shown to be mitogenic.'-' Thus, several parallel or interconnected pathways of stimulation might exist. To characterize surface components capable of inducing proliferation in human T lymphocytes, we prepared mAbs against T-cell components reactive with the mitogenic lectin leukoagglutinin from Phaseolus v~l g a r i s .~ '
Journal of Agricultural and Food Chemistry, 2007
Purification of the lectin from Phaseolus acutifolius var. escumite was achieved by affinity chromatography on a column containing glutaraldehyzed membranes from blood group O erythrocytes. The lectin is a tetrameric glycoprotein of 121 kDa with 10% of sugar by weight composed by four subunits of 30 kDa as determined by SDS-PAGE. The lectin is composed of four isolectins as determined by ion-exchange chromatography on a mono-S column. The lectin and its isolectins showed identical NH2 terminal residues (ANDLSFNFQR FNETN) with homology to the PHA leucoagglutinin-precursor. Peptide mass fingerprint from each lectin isoform determined from tryptic peptides by MALDI-TOF (matrix assisted laser desorption ionization-time-of-flight) showed differences among subunits, thus suggesting microheterogeneity in their amino acid sequences or different glycosylation patterns. The lectin and its four isolectins agglutinated erythrocytes without serological specificity and showed mitogenic activity on human leukocytes; moreover, the main effect was rather toward CD8+ than to CD4+ human peripheral lymphocytes. The lectin from escumite was not inhibitable by simple sugars; however, the specificity of the lectin and its isoforms was mainly addressed toward galactose residues present in bi-or triantennary N-acetyllactosamine-type glycans.
Journal of Experimental Medicine, 1979
We have analyzed the lectin binding characteristics of cytotoxic T lymphocyte (CTL)-derived surface labeled glycoproteins by affinity chromatography of the labeled glycoproteins on a panel of immobilized lectin adsorbents. Evidence is presented for the specific interaction of the CTL-associated glycoprotein T 145 with a lectin derived from Vicia villosa seeds. Conditions are described for the preparation and use of lectin affinity adsorbents for the rapid isolation of T 145 bearing cytotoxic T lymphocytes. Direct proof is given to show that T 145-positive cells arising from a variety of T-cell activations constitute the only subpopulation of cells with ability to perform cell-mediated T-cell cytotoxicity. Specific depletion of the CTLs by adherence to V. villosa adsorbents is shown by their depletion in the nonbound cell fraction and correspondingly enriched recovery in the sugar eluted cell fraction. Specific affinity fractionation of CTLs has occurred in every strain combination t...