The use of lectins in the quantitation and analysis of macromolecules by affinoelectrophoresis

The application of lectins to the characterization and isolation of mammalian cell populations

Mammalian cells invariably contain a vast array of glycosylated moieties, both inside the cell and on the cell surface. There is an increasing awareness of the utility of these carbohydrates in delineating the phenotype or function of many populations of cells. To this end lectins are extremely useful reagents. Lectins are carbohydrate-binding proteins and glycoproteins of non-immune origin derived from numerous plants and animals. A wide variety of lectins with many distinct carbohydrate specificities have been isolated. Historically the most common laboratory techniques utilizing lectins have been agglutination, mitogen stimulation, and fluorescence techniques. Recent advances in the development and conjugation procedure for labels and matrices have led to the creation of numerous novel lectin-based assays. Lectins are currently used not only to identify cells with specified carbohydrate groups, but also to quantitate the carbohydrate groups or to isolate the carbohydrate-bearing cells or structures.

Polyethylene glycol-enhanced nephelometric quantification of bovine submaxillary mucin with Helix pomatia lectin

A new principle for quantification of intact mucin has been developed. The method is reproducible, simple, and sensitive at the submicrogram level and can be performed within an hour. The procedure involves incubation of mucin (bovine submaxillary mucin) and polyethylene glycol with the lectin from the snail Helix pomatia and the complexes formed are quantitated by nephelometry. Polyethylene glycol was found to enhance the affinitin reaction in a dose-dependent fashion. Increasing concentrations of acetate or citrate led to decreasing light scattering of the polyethylene glycol--bovine submaxillary mucin--H. pomatia lectin reaction mixture. Results from displacement studies with N-acetyl-galactosamine suggest that H. pomatia lectin may contain an allosteric type of regulatory site. The quantitative results obtained with bovine submaxillary mucin using the new method correlated well with those obtained with an established method for neuraminic acid determination after neuraminidase digestion (R = 0.969, P less than 0.001; n = 24).

Interaction of anti-kojibiose antibody with the lipoteichoic acids from Streptococcus faecalis and Streptococcus faecium

Antisera prepared in rabbits by immunization with p-aminophenyl beta-kojibioside conjugated to bovine serum albumin (antikojibiose sera), readily agglutinated whole cells of Streptococcus faecalis or Streptococcus faecium, and showed specific reactions with the lipoteichoic acids (LTAs) of these streptococci by passive hemagglutination, microscale enzyme-linked immunosorbent assay, and crossed immunoelectrophoresis. The interaction of the antikojibiose sera with the LTAs was inhibited best by kojibiose [alpha-D-glucopyranosyl-(1----2)-D-glucose], somewhat less by the dextran from which the kojibiose was prepared, and not measurably by maltose [alpha-D-glucopyranosyl-(1----4)-D-glucose]. The sera reacted only minimally in only the most sensitive assay (microscale enzyme-linked immunosorbent assay) with LTA from group A streptococci (this LTA contains a single kojibiosyl residue as part of the glycolipid moiety of the molecule and failed to react with the Lactobacillus fermentum LTA which is substituted with alpha-D-galactopyranosyl-(1----2)-D -glucosyl units.

Effects of substitution on polyglycerol phosphate-specific antibody binding to lipoteichoic acids

The influence of D-alanine and carbohydrate substitution of lipoteichoic acids (LTAs) on the binding of antibody directed to the polyglycerol phosphate (PGP) portion was found to be at least partially dependent upon the mode of presentation of the antigen. There were greater differences in binding of anti-PGP immunoglobulins to substituted and unsubstituted LTAs in solution (micellar presentation) than when the same LTAs were adsorbed to the erythrocyte surface, which suggests that there is greater hindrance of access to the PGP chain, possibly as a result of closer packing, in a vesicle or micelle than when LTA is bound to a membrane surface. Although the difference in binding of anti-PGP immunoglobulins was nearly 20-fold between unsubstituted and highly substituted LTAs, rocket heights by rocket immunoelectrophoresis were only 4-fold different for the most highly substituted LTA and unsubstituted LTA. However, unsubstituted LTA clearly bound more immunoglobulin molecules than was reflected in the rocket height alone, since the resulting immunoprecipitates were much more prominent or intense, both before and after staining, than those of highly substituted LTAs. Differences between lightly and moderately substituted LTAs were less than twofold, indicating that under most circumstances estimates of LTA concentrations in samples where the composition is unknown will be within approximately twofold of the estimate.

Binding of mannosylated ferritin to chicken bone marrow macrophages

Ferritin conjugated to diazo p-aminophenylmannoside and mannan was used for ultrastructural visualization of binding and endocytosis via the mannose receptor. Conjugates were bound by live macrophages but not by glutaraldehyde-fixed cells. Binding was inhibited by 0.1 mM mannan and 0.2 M alpha-methylmannoside, and strongly reduced, but not abolished, after trypsin degradation of surface receptors. Binding sites were rapidly assembled on coated pits, which often showed a polar distribution on the cell surface and entered the cell following the direction of microtubuli. Some coated vesicles occasionally kept in touch with the extracellular space. 10-min exposure to the conjugate resulted in changes in the surface morphology, such as a loss of infoldings and increased membrane tension. Ferritin accumulated in large smooth vesicles with coated membrane regions. It was mostly detached from the membrane and agglutinated into big clumps, together with fibrillar material and small vesicles which may derive from the vesicle membrane.

Affinity electrophoresis of glycoproteins

Affinity electrophoresis is based on the reaction between interacting components during electro phoresis. In this review is given the general analytical technology. The main advantages of the analytical electrophoresis approach appear to be: 1. It can separate macromolecules that interact with a specific ligand from those that do not. 2. It can be used for studies of interacting macromolecules. 3. It is not necessary to purify interacting components. 4. A multitude of proteins reacting with the same ligand may be studied simultaneously. 5. It can be generalized to interactions other than those between lectins and glycoproteins.

F1-ATPase of Micrococcus lysodeikticus is not a glycoprotein

It has been claimed (Andreu, JM, Warth, R. and Muñoz, E. (1978) FEBS Letter, 86, 1-5) that the F1-ATPase of Micrococcus lysodeikticus is a glycoprotein containing mannose and glucose as the principal sugars. Even after extensive purification of M. lysodeikticus F1-ATPase by DEAE-Sephadex A25 chromatography, carbohydrate contents varying from 2.7 to 10.8% have been found. Concanavalin A-reactive components corresponding to the succinylated lipomannan have been detected and separated from the ATPase in purified F1 preparations by immunoelectrophoresis (rocket and two-dimensional) through agarose gels containing concanavalin A. Passage of the purified F1-ATPase through concanavalin A-Sepharose 4B columns removed the carbohydrate component(s) without loss of the specific activity of the ATPase. Mannose was the only sugar detectable by gas-liquid chromatography of the F1-ATPase before Con A-Sepharose 4B chromatography and it was completely eliminated after chromatography. No qualitative or quantitative changes in the subunit (alpha, beta, gamma, delta and epsilon) profiles were detectable when the sodium dodecyl sulfate polyacrylamide gels were scanned by densitometry of F1-ATPase before and after Con A-Sepharose 4B chromatography. We conclude that there is no evidence of carbohydrate covalently linked to this F1-ATPase and that this membrane protein is not a glycoprotein. The presence of carbohydrate is attributable to contamination with lipomannan.

Purification of the variant antigens of Trypanosoma congolense: a new approach to the isolation of glycoproteins

We describe a new and rapid method for the isolation and purification of the variant antigens of Trypanosoma congolense. The procedure consists of (a) partial lysis of trypanosomes with dioxane, (b) lectin-affinity-chromatography with Con A-Sepharose, (c) electrophoretic desorption and concomitant separation of Con A-Sepharose-bound glycoproteins in a granulated electrofocusing gel, (d) electrophoretic elution of focused proteins from the granulated gel particles. The efficiency of each step was followed quantitatively by affinity electrophoresis. 73% of the variant antigens originally present in a trypanosomal lysate could be recovered. From 10(10) trypanosomes 2 mg of pure variant antigen were obtained. The variant antigen of the trypanosome clone used exhibits heterogeneity in molecular weight as well as in electric charge.

Solubility characteristics of Micrococcus lysodeikticus membrane components in detergents and chaotropic salts analyzed by immunoelectrophoresis

In order to evalute the effectiveness and selectivity of various reagents in the solubilization of bacterial membranes, membranes of Micrococcus lysodeikticus were treated with detergents and chaotropic agents. The composition of the extracts so obtained was analyzed by rocket and two-dimensional immunoelectrophoretic techniques. Recoveery of succinate-, malate-, and reduced nicotinamide adenine dinucleotide- (NADH) dehydrogenases, ATPase, succinylated lipomannan and cytochromes in the extracts was measured. Treatment with a variety of non-denaturing detergents produced extracts that were generally qualitatively uniform although quantitative differences were observed. The degree of extraction of various components was correlated with the hydrophile-lipophile balance. Several chaotropic agents were also evaluated as reagents for membrane solubilization. These agents were less effective in extraction of bulk protein, but produced extracts enriched in some membrane components.

Combination of immunological and lectin reactions in affinity histochemistry: proposition of the term affinitin

Using the series system cell receptor leads to mistletoe lectin leads to antiferritin-antibody leads to ferritin, the possibilities for combination of lectin and immunological reactions for histochemistry are discussed. The system cell antigen leads to antibody leads to labelled mistletoe (or other) lectin is recommended for visualization of cell antigens (mistletoe lectin as common immunoglobulin reagent). It is pointed out that lectin reactions do not belong to immunhistochemistry but to affinity histochemistry. For all receptor specific proteins (antibodies, lectins, enzymes, haptoglobin and other) the term affinitin is proposed. In consideration of this new definition a common scheme is formulated: Affinitin reacts with affinitin receptor forming affinity product.

Immunochemical analysis of inner and outer membranes of Escherichia coli by crossed immunoelectrophoresis

Isolated membrane fractions of Escherichia coli K-12 yielded complex immunoprecipitate patterns when Triton X-100 and sodium dodecyl sulfate extracts were examined by crossed immunoelectrophoresis with antienvelope immunoglobulins. Twelve of the 46 antigens in the immunoprecipitate patterns of inner (plasma) membranes were identified by zymograms and/or by the use of specific antisera. The following enzyme activities were detected in immunoprecipitates: 6-phosphogluconate dehydrogenase (EC 1.1.1.43); adenosine triphosphatase (EC 3.6.1.3); glutamate dehydrogenase (EC 1.4.1.4), two separate components; malate dehydrogenase (EC 1.1.1.37); dihydroorotate dehydrogenase (EC 1.3.3.1); succinate dehydrogenase (EC 1.3.99.1); lactate dehydrogeanse (EC 1.1.1.27); reduced nicotinamide adenine dinucleotide dehydrogenase (EC 1.6.99.3); protease (EC 3.4.21.1); and glycerol 3-phosphate dehydrogenase (EC 1.1.99.5). The corresponding immunoprecipitate pattern for isolated outer membranes consisted of at least 25 discrete antigens and differed strikingly from that obtained with inner membranes. Two major immunogens were identified as lipopolysaccharide and Braun lipoprotein. A protease-active immunoprecipitate was also detected in this fraction, but attempts to identify the Rosenbusch matrix protein in the crossed immunoelectrophoretic profile were unsuccessful.

A set of analytical electrophoresis experiments to predict the results of affinity chromatographic separations: fractionation of allergens from cow's hair and dander

Analytical affinity electrophoresis experiments are described as analogues of column and batch affinity experiments. The are based on crossed immunoelectrophoresis with included affinity, here concanavalian A (con A) and con A-Sepharose. Reactions with serum proteins and allergens from cow's hair and dander are described, and a purification scheme for the latter is described.