Lectin receptors on the cell surface membrane and the kinetics of lectin-induced cell agglutination.

Agglutination of malignant transformed hamster cells by concanavalin A (ConA) and the lectins from wheat germ (WGA) and soybean (SBA) has been automatically quantitated, by measuring the amount of light transmitted through a cell suspension. The transformed hamster cells were agglutinated by SBA only after treatment with neuraminidase. The initial rate of agglutination and the concentration of lectin (K_c) required for the half-maximum rate (V_m) has been determined. The initial rate and V_m were lower and more temperature-sensitive, and the K_c was higher, for ConA than for WGA and SBA. There was no detectable temperature-dependent phase transition for the initial rate of agglutination. The total number of receptors was lower for ConA than for WGA and SBA and the apparent association constant between lectin molecules and cell surface receptors was higher for ConA (10⁷M^?1) than for WGA and SBA (1.6 × 10⁶M^?1). The half V_m of agglutination required 75% saturation of the cell receptors for ConA, and only 13–17% saturation of the receptors for SBA and WGA. A 30% decrease in the number of SBA receptors present in agglutinable cells completely prevented their agglutination. The results indicate that there is heterogeneity of lectin receptors on the cell surface and that only a small proportion of the total number of WGA and SBA receptors have to be occupied for agglutination by these lectins.     

Distribution of surface charge and concanavalin a-binding sites on normal and malignant transformed cells

Measurement of the rate of agglutination with the positively charged poly- -lysine of normal lymphocytes, Moloney-virus-transformed lymphoma cells, normal fibroblasts and SV40 transformed fibroblasts, has shown that the normal cells were agglutinated at a higher rate than the transformed cells. The labeling density of cationized ferritin in electron micrographs of sectioned cells, also indicated a higher charge density for the normal lymphocytes and fibroblasts. The normal cells showed a more regular clustered distribution of cationized ferritin than the transformed cells, and pre-fixation of cells with glutaraldehyde before labeling with cationized ferritin resulted in a random distribution in both types of cells. The transformed cells had a higher agglutinability than the normal cells by Concanavalin A (ConA) and this difference was also found after treatment of the cells with neuraminidase. Labeling with ConA-ferritin showed the same distribution on the sectioned normal and transformed cells. The results indicate that there was a difference in the redistribution of surface charge by cationized ferritin in normal and transformed cells and that there was no detectable difference in redistribution of ConA-binding sites with ConA-ferritin.     

Changing levels of uv light and carcinogen-induced unscheduled DNA synthesis in mouse oocytes during meiotic maturation.

The effects of cytochalasin B (CB) and colchicine on the lectin-mediated agglutination of dissociated cells from chick embryos at the early primitive streak stage were studied. Cells incubated in the absence of the above-mentioned drugs were agglutinable with concanavalin A (ConA), wheat germ agglutinin (WGA), and Ricinus communis agglutinin (RCA). A pre-incubation with neuraminidase was required to render the cells agglutinable with soybean agglutinin (SBA). This treatment had no appreciable effect on the agglutinability of the cells with the other three lectins. Treatment with the drug colchicine had no appreciable effect on the extent of agglutination with any of the above-mentioned lectins. Cells treated with CB dissolved in dimethylsulfoxide (DMSO) in saline, exhibited a reduced lectin-mediated agglutinability. However, a similar decline in agglutinability was observed in controls incubated in saline containing DMSO alone. It is suggested that structures sensitive to colchicine and CB do not play a major role in the control of surface lectin receptors in early embryonic cells.     

Effects of lysolecithin on the surface properties of human erythrocytes

Human red blood cells (RBCs), transformed by incubation with the amphiphatic compound lysolecithin from their normal discocyte shape into echinocytes, have increased rates of agglutination in the presence of either poly- -lysine (PLL) or soybean agglutinin (SBA). Removal of lysolecithin by washing caused a reversal of shape back to the discocyte configuration and a lowering of agglutination rates. Methochlorpromazine, another amphiphatic echinocytogenic substance produced a similar increase in agglutination rates, suggesting that increased agglutinability may be a general property of echinocytes. Lysolecithin treatment of RBCs caused a decrease in the binding of cationized ferritin (CF) particles/μm² of RBC surface. The decrease in CF binding is due to a rearrangement of negative charge bearing molecules on the RBC surface rather than shedding of charged groups. These observations support the hypothesis that integral membrane proteins which bear negative charges and receptors are associated with a cytoskeleton within the red cell. Alterations in cell shape which result in distortion of the cytoskeleton may cause a redistribution of integral membrane proteins which bear charged groups at the RBC surface.     

大豆凝集素的纯化及其凝集不同肿瘤细胞的探讨

大豆凝集素 (SBA)能特异识别N 乙酰氨基半乳糖 (GalNAc)或半乳糖 (Gal) ,引起兔红细胞凝集[1] .正常人体细胞表面糖链上的GalNAc或Gal通常被唾液酸分子覆盖 ,不能被SBA识别 .新近研究表明 ,能被SBA特异识别的异常糖链可在多种恶性肿瘤细胞上表达 ,包括 :大鼠乳腺癌细胞系R32 30AC[2 ] ,小鼠乳腺肿瘤细胞系TPDMT 4 [3 ] ,小鼠T细胞肝转移淋巴瘤L5 178Y F9、SL2 5 [4] ,小鼠Lewis肺癌细胞[5] ,人类结肠癌细胞系HT2 9、SW12 2 2 [6] ,人类胰腺癌细胞系Hup T3、Hup T4 [7] ,人类乳腺癌细胞系T 4 7D[8] ,附睾乳头状囊腺癌[9] …     

Lectin-mediated sperm agglutination of bufo arenarum and leptodactylus chaquensis spermatozoa

Various plant lecins were employed in cell agglutination experiments to ascertain the presence of specific saccharides in the surface of B arenarum and L chaquensis spermatozoa. B arenarum spermatozoa were specifically agglutinated with Concanavalin A (Con A), phytohemagglutinin P (PHA-P), and wheat germ agglutinin (WGA), but not with soybean agglutinin (SBA). In contrast, L chaquensis spermatozoa were strongly agglutinated by SBA, WGA, and PHA-P. L chaquensis spermatozoa did not agglutinate with Con A even at high concentrations. Lectinmediated sperm agglutination was inhibited in the presence of specific lectinbinding sugars. Spermatozoa from both species were agglutinated randomly with all lectins suggesting a uniform distribution in the sperm surface of the lectinbinding saccharide ligands. B arenarum sperm agglutination induced by Con A is sensitive to temperature. B arenarum spermatozoa are more agglutinable at 24°C than at 4°C. These results suggest that lectin-binding site mobility is necessary for sperm agglutination.     

Plasmodium berghei: modification of sialic acid on red cells from infected mouse blood

The surface membrane glycoproteins of normal mouse erythrocytes can be labeled by oxidation with either periodate or galactose oxidase in the presence of neuraminidase, followed by reduction with NaB³H₄. Without neuraminidase there is little galactose oxidase-catalyzed labeling of protein. Analysis of labeled proteins by SDS-polyacrylamide gel electrophoresis showed that both methods labeled the same set of glycoproteins. Plasmodium berghei infection dramatically reduced the sialoglycoprotein labeling of red blood cells from infected blood using the periodate/NaB³H₄ method. Provided neuraminidase was present, labeling by the galactose oxidase method gave identical results to normal erythrocytes. We conclude that the glycoprotein sialic acid of uninfected as well as infected red cells is modified during infection such that it is refractory to periodate oxidation. Acylation of the exocyclic hydroxyls of sialic acid is suggested to account for this. Lectin binding and cell agglutination experiments using Limulin, soybean and wheatgerm lectins, and concanavalin A confirmed and extended these observations. The possible implications of these results with regard to anemia induced by malaria are briefly discussed.     

Trypsinization increases lectin-induced agglutinability of uncapacitated guinea pig sperm

Capacitated guinea pig sperm are more agglutinable by the lectin soybean agglutinin (SBA) than uncapacitated sperm (Talbot and Franklin, '78). This study demonstrates that uncapacitated guinea pig sperm become as agglutinable by SBA as capacitated sperm when treated with trypsin, but not chymotrypsin. The pattern of lectin induced sperm agglutination after trypsinization resembles that for capacitated sperm. Also, trypsinization specifically increases SBA induced agglutination and does not affect agglutination by RCA-60; similar results are obtained during in vitro capacitation. Taken together, these data may indicate that a trypsin-like enzyme modifies the sperm surface during capacitation.     

Trypanosoma rhodesiense Bloodstream Trypomastigote and Culture Procyclic Cell Surface Carbohydrates1, 2, 3

Bloodstream trypomastigote and culture procyclic (insect midgut) forms of a cloned T. rhodesiense variant (WRATat 1) were tested for agglutination with the lectins concanavalin A (Con A), phytohemagglutinin P (PP), soybean agglutinin (SBA), fucose binding protein (FBP), wheat germ agglutinin (WGA), and castor bean lectin (RCA). Fluorescence-microscopic localization of lectin binding to both formalin-fixed trypomastigotes and red cells was determined with fluorescein isothiocyanate (FITC)-conjugated Con A, SBA, FBP, WGA, RCA, PNA (peanut agglutinin), DBA (Dolichos bifloris), and UEA (Ulex europaeus) lectins. Electron microscopic localization of lectin binding sites on bloodstream trypomastigotes was accomplished by the Con A-horseradish peroxidase-diaminobenzidine (HRP-DAB) technique, and by a Con A-biotin/avidin-ferritin method. Trypomastigotes, isolated by centrifugation or filtration through DEAE-cellulose or thawed after cryopreservation, were agglutinated by the lectins Con A and PP with agglutination strength scored as Con A < PP. No agglutination was observed in control preparations or with the lectins WGA, FBA or SBA. Red cells were agglutinated by all the lectins tested. Formalin-fixed bloodstream trypomastigotes bound FITC-Con A and FITC-RCA but not FITC-WGA, -SBA, -PNA, -UEA or -DBA lectins. All FITC-labeled lectins bound to red cells. Con A receptors, visualized by Con A-HRP-DAB and Con A-biotin/avidin-ferritin techniques, were distributed uniformly on T. rhodesiense bloodstream forms. No lectin receptors were visualized on control preparations. Culture procyclics lacked a cell surface coat and were agglutinated by Con A and WGA but not RCA, SBA, PP and FBP. Procyclics were not agglutinated by lectins in the presence of competing sugar at 0.25 M. The expression of lectin binding cell surface saccharides of T. rhodesiense WRATat 1 is related to the parasite stage. Sugars resembling α-D-mannose are on the surface of bloodstream trypomastigotes and culture procyclics; n-acetyl-D-galactosamine and D-galactose residues are on bloodstream forms; and n-acetyl-D-glucosamine-like sugars are on procyclic stages.     

Trypanosoma rhodesiense bloodstream trypomastigote and culture procyclic cell surface carbohydrates

Bloodstream trypomastigote and culture procyclic (insect midgut) forms of a cloned T. rhodesiense variant (WRAT at 1) were tested for agglutination with the lectins concanavalin A (Con A), phytohemagglutinin P (PP), soybean agglutinin (SBA), fucose binding protein (FBP), wheat germ agglutinin (WGA), and castor bean lectin (RCA). Fluorescence-microscopic localization of lectin binding to both formalin-fixed trypomastigotes and red cells was determined with fluorescein isothiocyanate (FITC)-conjugated Con A, SBA, FBP, WGA, RCA, PNA (peanut agglutinin), DBA (Dolichos bifloris), and UEA (Ulex europaeus) lectins. Electron microscopic localization of lectin binding sites on bloodstream trypomastigotes was accomplished by the Con A-horseradish peroxidase-diamino-benzidine (HRP-DAB) technique, and by a Con A-biotin/avidin-ferritin method. Trypomastigotes, isolated by centrifugation or filtration through DEAE-cellulose or thawed after cryopreservation, were agglutinated by the lectins Con A and PP with agglutination strength scored as Con A greater than PP. No agglutination was observed in control preparations or with the lectins WGA, FBA or SBA. Red cells were agglutinated by all the lectins tested. Formalin-fixed bloodstream trypomastigotes bound FITC-Con A and FITC-RCA but not FITC-WAG, -SBA, -PNA, -UEA or -DBA lectins. All FITC-labeled lectins bound to red cells. Con A receptors, visualized by Con A-HRP-DAB and Con A-biotin/avidin-ferritin techniques, were distributed uniformly on T. rhodesiense bloodstream forms. No lectin receptors were visualized on control preparations. Culture procyclics lacked a cell surface coat and were agglutinated by Con A and WGA but not RCA, SBA, PP and FBP. Procyclics were not agglutinated by lectins in the presence of competing sugar at 0.25 M.(ABSTRACT TRUNCATED AT 250 WORDS)     

Location of glycoproteins on milk fat globule membrane by scanning and transmission electron microscopy, using lectin-labelled gold granules

Membrane glycoproteins of bovine and human milk fat globules (MFG) were located by scanning electron microscopy using lectin-labelled gold granules (50 nm diameter) as specific markers. Receptors for wheat germ agglutinin (WGA) and soybean lectin (SBA) were localized in clusters over the whole MFG surface. When MFG were treated with neuraminidase, the density of marking with SBA increased. Marking of MFG with Concanavalin A (ConA) was weak. No marking was obtained with lectins specific for -fucose, -galactose and α- -galactose. When thin sections of MFG marked with WGA (18 nm diameter gold granules) were examined by transmission electron microscopy, the membrane was uniformly marked. Using markers of different sizes (5 and 18 nm diam.) prefixed milk fat globule membranes (MFGM) were simultaneously marked with WGA and SBA. The lectin receptors appeared to belong to different glycoproteins which were clustered. Thin sections of this material showed that the receptors were located on one side of the membrane. No difference was observed between bovine MFG and human MFG from donors having blood group O and A. All results indicated that MFGM is a true biological membrane.     

Agglutination and fusion of globoside GL-4 containing phospholipid vesicles mediated by lectins and calcium ions

We have investigated the interaction of five N-acetylgalactosamine (GalNAc) specific lectins with the glycosphingolipid globoside GL-4, inserted into phospholipid vesicles composed of phosphatidyl-ethanolamine and phosphatidic acid, with respect to their ability to induce vesicle agglutination, fusion, and destabilization. The following lectins were used: soybean agglutinin (SBA); Sophora japonica agglutinin (SJA); Helix pomatia agglutinin (HPA); Ricinus communis agglutinin II (RCAII); and Codium fragile agglutinin (CFA). SBA and SJA caused rapid vesicle agglutination while HPA, CFA, and RCAII were ineffective. However, in the presence of RCAII, but not HPA and CFA, the addition of Ca2+ caused vesicle agglutination which was specifically inhibited by the haptenic sugar GalNAc, while ethylenediaminetetraacetic acid (EDTA) dissociated the vesicle complex. RCAII/Ca2+-induced vesicle agglutination was accomplished by binding of Ca2+ to RCAII after the lectin/receptor interaction. The rate of SBA-induced vesicle agglutination was increased in the presence of Ca2+, independent of the order of Ca2+ addition, and was not reversed by EDTA, indicating that the mechanism by which Ca2+ stimulated agglutination in this case was different from that observed in the presence of RCAII. In contrast to RCAII/Ca2+, SBA/Ca2+ induced of the vesicles, which occurred only when Ca2+ was added after lectin addition. Close approach of adjacent bilayers was accomplished by nonspecific interactions of SBA with the bilayer after lectin binding to the receptor as revealed by a limited extent of SBA-induced fusion and an enhanced membrane permeability upon lectin binding. The phenomena observed can be explained in terms of a Ca2+-modulated reorientation of the carbohydrate head group, causing it to adopt a more perpendicular orientation with respect to the plane of the bilayer.(ABSTRACT TRUNCATED AT 250 WORDS)     

Differences between normal and scaleless (sc/sc) chicken epidermal cell surfaces detected with wheat germ agglutinin

Dissociated epidermal cells derived from the backskin of scaleless chick embryos (stage 34 or 35) form larger agglutinates with wheat germ agglutinin (WGA) than epidermal cells from normal embryonic skin. [³H]Acetyl WGA binding to the scaleless cells is twice as great as to normal epidermal cells. Treatment of these cells with concanavalin A (conA) results in equivalent agglutination of both mutant and normal epidermal cells, whereas neither scaleless nor normal epidermal cells are agglutinated by Dolichos biflorus agglutinin (DBA), soybean agglutinin (SBA) or Ulex europeus agglutinin (UEA). This alteration in cell surface carbohydrates may be related to the failure of the scaleless mutant embryonic epidermis to undergo normal morphogenesis.     

Lectin binding to neural crest cells. Changes of the cell surface during differentiation in vitro

To examine possible changes in cell surface carbohydrates, fluorescent lectins were applied at various times during differentiation of neural crest cells in vitro. The pattern and intensity of binding of several lectins changed as the crest cells developed into melanocytes and adrenergic cells. Considerable amounts of concanavalin A (Con A) and wheat germ agglutinin (WGA) bound to all unpigmented cells throughout the culture period. Melanocytes, however, bound much less of these lectins. Soy bean agglutinin (SBA), unlike Con A and WGA, only bound later in development to unpigmented cells at about the time when catecholamines were detected histochemically. Binding of SBA could be induced in younger cultures by pretreating the cells with neuraminidase. Melanocytes, however, did not bind detectable amounts of SBA even if treated with neuraminidase. The SBA-binding sites were often concentrated on cytoplasmic extensions and on contact points between neighboring cells, even when receptor mobility was restricted by prefixation of the cells or adsorption of lectin at 0 degrees C. All three lectins bound to cell processes resembling nerve fibers in particularly high amounts.     

Identification of glycolipid binding sites for soybean agglutinin and differences in the surface glycolipids of cultured adrenergic and cholinergic sympathetic neurons

Cultured adrenergic neurons from newborn rat superior cervical ganglia bind the lectin soybean agglutinin (SBA) at a fivefold higher density than the same neurons which have been induced to become cholinergic (M. Schwab and S. L. Landis, 1981, Dev. Biol.84, 67–78). In the present experiments, the binding sites for this lectin on the surfaces of living neurons were identified by labeling the surfaces with the galactose oxidase-[³H]sodium borohydride reduction technique, with and without prior incubation with the lectin. SBA binds to and inhibits the labeling of two neutral glycolipids, a glycolipid comigrating with globoside on thin-layer chromatograms and an unidentified glycolipid. When neuronal proteins are extracted and separated by polyacrylamide gel electrophoresis in sodium dodecyl sulfate, SBA shows only very faint labeling of this fraction. Thus the SBA binding sites on these neurons appear to be two neutral glycolipids. Further support for this conclusion comes from the finding that the two neutral glycolipids detected by SBA are present in smaller amounts or are less accessible on the cholinergic than on the adrenergic neurons as measured by surface labeling. In addition to the difference in neutral glycolipids, external labeling revealed quantitative differences in the major gangliosides of the two types of cultured neurons. Thus, by using pure cultures of sympathetic neurons which can be induced to become either adrenergic or cholinergic, specific glycolipid profiles were correlated with the two neurotransmitter phenotypes.     

Activation of mouse peritoneal macrophages alters the structure and surface expression of protein-bound lactosaminoglycans

We have begun to analyze and compare the surface carbohydrates present on populations of resident and activated mouse peritoneal macrophages. The activated macrophage populations studied include TG-elicited macrophages, BCG-activated macrophages, and resident macrophages cultured for 24 hr in the presence of lymphokines or heterologous serum. Analysis of glycopeptides generated by pronase digestion of surface glycoproteins labeled by the neuraminidase/galactose oxidase/NaB3H4 method indicates that the macrophage surface contains a class of high m.w. carbohydrates susceptible to degradation by endo-beta-galactosidase, lactosaminoglycans. These lactosaminoglycans are sialylated type 2 carbohydrates containing the repeating lactosamine disaccharide Gal beta 1-4GlcNAc as well as fucose residues. Macrophage activation was observed to markedly alter surface lactosaminoglycans. The alterations observed include 1) an increase in surface expression as determined by both an increase in neuraminidase/galactose oxidase/NaB3H4 labeling and by the ability of activated but not resident macrophages to bind I antibodies as assayed by indirect immunofluorescent surface staining, 2) the addition of alpha-galactose residues, and 3) an increase in GlcNAc beta 1-6Gal branching as indicated by an increased resistance to endo-beta-galactosidase degradation and by the ability of activated macrophages to bind I antibodies. These observations demonstrate that macrophage activation results in specific and substantial alterations in protein-bound surface carbohydrates.     

Carbohydrate patterns of the pure cholinergic synapse of Torpedo electric organ: a cytochemical and immunocytochemical electron microscopic approach.

Using post-embedding gold staining techniques, we investigated the ultrastructural distribution of terminal sugars and carbohydrate chains located at the pure cholinergic electric organ tissue of Torpedo marmorata. Neither alpha-N-acetylgalactosamine (GalNAc)-specific lectins (DBA, SBA, HPA) nor monoclonal antibodies (MAb) recognizing Tn (Gal-NAc alpha-O-Ser/Thr; MAb Cu-1) and sialyl-Tn epitopes (NeuAc alpha 2,6GalNAc alpha-O-Ser/Thr; MAb B72.3 and OSM-10) were capable of labeling any of the synaptic structures. The absence of gold labeling was likewise noted with UEA-I (L-fucose) and with PNA (T-antigen, Gal beta 1,3GalNAc alpha). After neuraminidase pre-treatment of ultra-thin sections, PNA labeling was rendered evident, indicating the presence of neuraminic acid-masked T-antigen. Certain synaptic vesicles were labeled for neuraminic acid (LFA) and for N-acetyllactosamine (DSA), whereas others were not labeled at all. Gold labeling with LFA, RCA-I (beta-galactose), and DSA in the membrane infoldings of the dorsal face of the electrocyte was visualized. As noted above, the PNA reaction was revealed only after pre-treatment with neuraminidase. Dorsal (non-synaptic) basal lamina were reactive with DSA, whereas the synaptic portion was likewise labeled with LFA and RCA-I. Finally, RCA-I labeling was noted in the Schwann cell nucleus. Comparisons between these results and those described at the neuromuscular junction were made.     

Phagocytosis of senescent erythrocytes by autologous monocytes: requirement of membrane-specific autologous IgG for immune elimination of aging red blood cells

The role of membrane-bound IgG present on the membrane of senescent erythrocytes in immune eliminations of aging red cells was investigated. Phagocytosis of populations of red blood cells (RBC) of different ages by autologous monocytes was assessed both by direct phagocytosis and by induction of microsomal heme oxygenase. Removal of IgG from older RBCs inhibited their phagocytosis; in contrast, preincubation of neuraminidase-treated young or in vitro aged RBCs with IgG eluted from old cells led to phagocytosis of RBCs treated by autologous monocytes. It was also found that the Fc portion of membrane-bound IgG is essential for the elimination of senescent cells; less than 15% of old heat-inactivated RBCs coated with F(ab)2 fragment of membrane-bound IgG were phagocytosed. In contrast, more than 50% of old heat-inactivated RBCs coated with heat-eluted IgG were phagocytosed by autologous monocytes. A possible mechanism of elimination of aged cells is discussed.     

Localization of penultimate carbohydrate residues in zona pellucida and acrosomes by means of lectin cytochemistry and enzymatic treatments

Lectins from peanuts (PNA) and soy beans (SBA) bind terminal residues of galactose (Gal) and N-acetyl-galactosamine (GalNAc) respectively. Galactose oxidase oxidizes the hydroxyl group at C-6 of terminal Gal and GalNAc blocking the binding of PNA and SBA. Binding of these lectins to sugar residues is also severely limited by the existence of terminal residues of sialic acid. In the present study, lectin cytochemistry in combination with enzymatic treatments and quantitative analysis has been applied at light and electron microscopical levels to develop a simple methodology allowing the in situ discrimination between penultimate and terminal Gal/GalNAc residues. The areas selected for the demonstration of the method included rat zona pellucida and acrosomes of rat spermatids, which contain abundant glycoproteins with terminal Gal/GalNAc residues. Zona pellucida was labelled by LFA, PNA and SBA. After galactose oxidase treatment, terminal Gal/GalNAc residues are oxidized, and reactivity to PNA/SBA is abolished. The sequential application of galactose oxidase, neuraminidase and PNA/ SBA has the following effects: (i) oxidation of terminal Gal/GalNAc residues; (ii) elimination of terminal sialic acid residues rendering accessible to the lectins preterminal Gal/GalNAc residues; and (iii) binding of the lectins to the sugar residues. Acrosomes were reactive to PNA and SBA. No LFA reactivity was detected, thus indicating the absence of terminal sialic acid residues. Therefore, no labelling was observed after both galactose oxidase--PNA/SBA and galactose oxidase--neuraminidase--PNA/SBA sequences. In conclusion, the combined application of galactose oxidase, neuraminidase and PNA/SBA cytochemistry is a useful technique for the demonstration of penultimate carbohydrate residues with affinity for these lectins. This revised version was published online in November 2006 with corrections to the Cover Date.     

Cell surface and clonal proliferative property of aging human diploid fibroblasts

We have described previously how concanavalin A (conA)-coated red blood cell (RBC) adsorption to human diploid fibroblasts could serve as a marker of the in vitro aging of these cells. Since the heterogeneity in RBC adsorption and the proliferative property of young and old cell populations was observed, the correlation of this cell surface property with the proliferative behavior of individual clones was examined as a function of cell age. The RBC adsorption capacity of cells in both large and small colonies changed with the aging of the parent cell populations; the cells from early passage populations did not adsorb RBCs, but those from late passage populations adsorbed them well. Thus, the amount of RBC adsorption was not a function of colony size, but was related to the age of the culture.