Biomedical subjects

B A Dalton

Publications and source records attributed to B A Dalton.

At least 19 recordsLinked to original sources

PubMed2003

Polymer design for corneal epithelial tissue adhesion: pore density.

A porous polymer is required to sustain corneal epithelial tissue on the anterior surface of an implantable contact lens (corneal onlay). Porosity creates topography on the polymer surface and, if defined, this can be manipulated to elicit a particular tissue response. Previous work identified pores of 100-nm diameter to be the critical size of a discontinuity in a polymer surface to facilitate the migration, stratification, and sustained adhesion of corneal epithelial tissue. Now we address the issue of pore density. Corneal epithelial tissue was grown for 21 days on nonporous polycarbonate and polycarbonate track-etched with pores 100-nm diameter with pore densities ranging from 0.27 and 14.4% of the total polymer surface area. Histology was used to score epithelial structure, and electron microscopy was used to quantitate the formation of adhesive structures (basal lamina and hemidesmosomes) at the tissue-polymer interface. Data showed that epithelial tissue stratified and epithelial adhesive structures formed on polycarbonate surfaces with pore densities between 0.52 and 14.4% inclusive. This means that epithelial tissue can be maintained on a polymer where up to 14.4% of the surface is dedicated to small discontinuities in the form of pores 100-nm diameter. These figures can be used to specify the design of a polymer for applications requiring epithelial cover.

Animals↗

PubMed2002

Transforming growth factor-beta 1, 2, and 3 can inhibit epithelial tissue outgrowth on smooth and microgrooved substrates.

In this study, we describe the influence of parallel surface microgrooves, and of TGF-beta, on the outgrowth of corneal epithelial tissue. Microgrooves (depth 1 microm, width 1-10 microm) were made in polystyrene culturing surfaces. These surfaces were left untreated, or loaded with TGF-beta 1, 2, or 3 (6.0 ng/cm(2)). Subsequently, epithelial explants from bovine corneas were placed on the experimental surfaces. After 9 days of culturing, tissue outgrowth was evaluated. Furthermore, the tissue cultures were analyzed histologically. It was shown that epithelial tissue grew from the explants over all experimental surfaces. On microgrooved surfaces outgrowth proceeded in the direction of the grooves, rather than perpendicular to the grooves. The addition of each type of TGF-beta resulted in a reduction of outgrowth. However, outgrowth remained directed by the grooves. Further, the explants had shrunk after TGF treatment. Histology showed that this shrinkage was not related to alpha-smooth muscle actin expression in the explants. We conclude that microgrooves can direct, and TGF-betas can inhibit the outgrowth of epithelial tissue. This finding could be useful in biomaterial applications where the growth of epithelial tissue needs to be discouraged.

Animals↗

PubMed2001

Stimulation of epithelial tissue migration by certain porous topographies is independent of fluid flux.

A surface with columnar pores 0.1 or 0.4 microm in diameter is shown to have a novel effect on the migration of corneal epithelial tissue sheets; migration is stimulated in a nondirectional manner with respect to migration over a planar, nonporous surface (Dalton, Evans, McFarland, and Steele, J Biomed Mater Res 1999;45:384-394; Steele, Johnson, McLean, Beumer, and Griesser, J Biomed Mater Res 2000;50:475-482). By blind-ending the pores, we show that this increase in tissue migration is not dependent on fluid flux through the pores and so appears to occur as a result of surface topography. From transmission electron micrographs, the migrating tissue appears to form either close contacts or focal adhesions at the edge of some pore channels; we speculate that this may provide a fulcrum for the enhanced migration. Scanning electron micrographs suggest that within tissue that migrates over the surfaces that contain blind-ended pores, the cells are more extensively spread than those in tissue migrating on a planar surface. The migration of disaggregated epithelial cells is enhanced on surfaces that contain 0.1- or 0.4-microm-diameter pores (compared with a planar surface), and this is similarly independent of fluid flux.

Animals↗

PubMed2001

Modulation of epithelial tissue and cell migration by microgrooves.

We used a polystyrene substratum to study the response of migrating epithelium to 1- or 5-microm depth microgrooves with groove/ridge widths of 1, 2, 5, or 10 microm. The migration of a tissue sheet was enhanced along the microgrooves, while migration across the microgrooves was inhibited. Changing the depth of the microgrooves had a greater effect on migration than alteration of the groove/ridge width. The migration of epithelial cells from a confluent monolayer culture followed a similar pattern to that of intact epithelial tissue. Cellular extensions generally followed the microgroove direction by tracking along the top of the ridges or following the ridge walls, as revealed by scanning electron microscopy. Actin filaments within the basal cell layer of the tissue were aligned with the microgrooves, unlike filaments in the superficial layers that did not appear to be affected by the presence of underlying microgrooves. The basal cell layer of the tissue conformed to the contours of the microgroove following migration. However, the ultrastructure of the tissue above the ridges resembled that of tissue on a flat surface. We concluded that surface microgrooves have the potential to direct the migration of immediately adjacent epithelial tissue, the effect of which is to guide epithelial tissue on the surface of implanted biomaterials.

Actin Cytoskeleton↗

PubMed2001

Migration mechanisms: corneal epithelial tissue and dissociated cells.

The migratory mechanism of intact bovine corneal epithelial tissue and individual corneal epithelial cells over synthetic surfaces in vitro were compared. In migrating tissue, adhesion between component cells was demonstrated by immunostaining for desmoplakin and identification of desmosomes by electron microscopy. The apparent intermeshing of microtubules within the tissue and interdigitation of cytoplasmic membranes showed the close association of cells. Portions of the advancing edge of the tissue contained actin filaments that were orientated parallel to the leading tissue front. These filaments appeared to span adjacent cells suggesting that migration partially involved the contraction of the actin cable, similar to the 'purse-string' mechanism originally identified in the closure of fetal skin wounds. Intact actin filaments and microtubules were necessary to maintain optimum migration rates for tissue and cells. However, tissue morphology was not dependent on microtubule integrity. During the migration of individual epithelial cells, no staining for desmoplakin was observed and there were clear divisions between the microtubules of adjacent cells. Actin filaments tended to be arranged parallel to the direction of cell movement.Therefore, migration of epithelial tissue sheets over synthetic surfaces occurs by mechanisms that differ from the migration of individual epithelial cells. Model systems based on the migration of intact tissue would give a more realistic assessment of the suitability of a material for biomaterial applications than the use of separate epithelial cells.

Actin Cytoskeleton↗

PubMed1999

Persistent adhesion of epithelial tissue is sensitive to polymer topography.

The persistent adhesion of corneal epithelial tissue to the surface of a porous polymer is of interest in the development of a corneal onlay. Using an in vitro model system, this study examined the effect of polymer surface topography on the assembly of basement membrane and hemidesmosomes. Corneal epithelial tissue was grown on polycarbonate surfaces with a range of pore sizes (0.1-3.0 micron, pore diameter) and an equivalent nonporous surface. The ultrastructure of the tissue-polymer interface was evaluated using electron microscopy. On the porous surfaces, the tissue responded to a balance between the size of the discontinuity (pores) and the amount of polymer surface between the pores. Continuous basement membrane and a regular pattern of hemidesmosomal plaque occurred only on the 0.1 micron surface, where both the pores and the total surface area covered by pores were relatively small. The assembly of adhesive structures on surfaces with pore diameters between 0.4-2.0 microns was restricted to regions of polymer between pores. No adhesive structures assembled on the nonporous or on the 3.0-micron surface. These results demonstrate that, in addition to porosity, surface topography is a significant factor in the formation of structures involved in the persistent adhesion of stratified epithelial tissue on a polymer.

Animals↗

PubMed1999

Modulation of corneal epithelial stratification by polymer surface topography.

The topography and porosity of a polymer may affect the epithelialization of a corneal implant. We used an in vitro model to examine the effect of polymer surface topography on corneal epithelial tissue stratification and the deposition of proteins associated with epithelial adhesion. A range of topographies was provided by polycarbonate membranes with nominal pore diameters of 0.1, 0.4, 0.8, 1.0, 2.0, or 3.0 microm and a nonporous surface. Stratification of epithelial tissue outgrowth on these surfaces was evaluated using light and electron microscopy. Deposition of proteins associated with basement membrane and adhesion complex formation at the tissue-polymer interface was assessed using immunohistochemistry. Surfaces with pores in the 0.1-0.8-microm-diameter range supported superior stratification and protein deposition compared with those containing pores of > or = 1.0 microm. Cytoplasmic processes penetrated single pores 2.0 and 3.0 microm in diameter and fused pores 1.0 microm in diameter. Tissue on the nonporous surface had a lower level of stratification compared with surfaces with pores 0.1-0.8 microm in diameter. These results point to the significance of surface topography in biomaterial applications that require persistent epithelialization.

Animals↗

PubMed1999

Attachment of cultured human bone cells to novel polymers.

The initial attachment of human bone-derived cells (HBDC) to several polymer systems has been studied in vitro. A novel polymer system based on poly(ethyl methacrylate) polymer and tetrahydrofurfuryl methacrylate monomer (PEMA/THFMA) was compared with a variant in which THFMA was replaced by 2-hydroxyethyl methacrylate (PEMA/HEMA). Tissue culture polystyrene (TCPS) and polystyrene (PS) were used as reference materials. The ability of the substrates to adsorb the attachment glycoproteins fibronectin (Fn) and vitronectin (Vn) from serum and the subsequent effect on radiolabeled HBDC attachment were examined. Initial cell attachment from the medium containing 10% (v/v) serum was highest on TCPS; on PEMA/THFMA and PEMA/HEMA substrates it was about 25% of this level, and on PS it was only 10% of that on TCPS. Attachment of HBDC to all substrates was dependent on the presence of Vn, which, unlike Fn, was able to adsorb in the face of competition from other serum components. Both Vn and Fn were able to support cell attachment when precoated onto all substrates. In comparison to TCPS, PEMA/THFMA did not show enhanced adsorption of either Fn or Vn from serum, and this was reflected in the level of cell attachment. Interestingly, the potency of preadsorbed Fn for cell attachment was much higher on this substrate than on any other: 45 ng/cm2 Fn when adsorbed to PEMA/THFMA gave a level of cell attachment 1.6-fold higher than the same density of Fn on PS or TCPS. The maximum Fn surface density achieved on HEMA/PEMA was 16 ng/cm2. Cells on PEMA/THFMA showed typical clustering of the alpha5 beta1 Fn receptor, but this was not evident in cells attached to PEMA/HEMA even when precoated with Fn. This study indicates that the initial attachment of HBDC to all substrates was Vn dependent. It also indicates that on PEMA/THFMA the favorable presentation of subsequently adsorbed Fn may assist matrix assembly.

Biocompatible Materials↗

PubMed1998

Surface topography can interfere with epithelial tissue migration.

Corneal epithelial tissue migration over the surface of a synthetic polymer can be inhibited by pores in the substrate. The effects of this substrate topography upon epithelial tissue migration were studied in vitro. Membranes of different porosities and structures were used to provide two series of surfaces having a graded increase in discontinuities: cellulose nitrate/acetate membranes with a tortuous network of pores, and track-etched polycarbonate membranes with columnar pores. Corneal epithelial tissue outgrowth was inhibited by increased pore size, and for both series of membranes, outgrowth was completely halted on membranes with mean diameter of the pores 0.9 microm at the pore densities measured. On the track-etched membranes with pores of <0.9 microm diameter, tissue outgrowth could be partially "rescued" by coating with fibronectin or collagen, but above this size, the inhibition predominated. The effect of porosity of the track-etched membranes upon the migration of dissociated epithelial cells was also examined. Although migration of these cells was reduced on membranes having pore sizes larger than 0.9 microm, it was not completely inhibited even on membranes of 2.3-microm pore diameter. Therefore, tissue movement of adult stratified epithelium may be inhibited by specific surface topographies, and in this assay system, epithelial tissue outgrowth was more affected than was the migration of dissociated epithelial cells.

Animals↗

PubMed1998

Polymer surface chemistry and bone cell migration.

Implant devices for orthopaedic applications may be improved if the surface of the biomaterial provides for osteointegration. To understand the effect of hydrophilicity on colonisation by human bone derived (HBD) cells, we compared untreated polystyrene (PS) and a sulfuric acid-treated PS surface for mechanisms of cell migration. The chemical composition of the acid-treated PS surface was analysed by monochromatic X-ray photoelectron spectroscopy and found to contain various oxidatively produced groups and a minor amount of sulfonate groups. It was found that migration of HBD cells on both PS and acid-treated PS surface was dependent on the presence of vitronectin (Vn) and was higher on the hydrophilic acid-treated surface. Minimal migration of HBD cells occurred on either surface in the absence of Vn, even when fibronectin was present in the culture medium. Using radiolabelled protein, it was shown that Vn adsorption onto the acid-treated surface was two to three fold greater than that on the hydrophobic PS. When HBD cells were seeded onto a patterned surface in a medium containing Vn, the cells preferentially colonised the hydrophilic region and few, if any, cells traversed the haptotactic boundary from the hydrophilic to the hydrophobic side. Thus the enhanced HBD cell migration seen on the acid-treated PS compared with the untreated PS surface and the haptotactic boundary phenomenon, relate to Vn adsorption.

Adolescent↗

PubMed1996

Measurement of cell adhesion and migration using phosphor-screen autoradiography.

This study demonstrates the use of phosphor-screen autoradiography as a means of measuring cell adhesion and cell expansion on polymer surfaces. The method has particular merit in cases where a specific substrate may be opaque or biochemically incompatible with colorimetric assay methodologies. With the phosphor-screen autoradiography method, there was a linear relationship between cell number and quantitated radioactivity. The technique has also been validated by comparison with a colorimetric assay of adhesion conducted for attachment to conventional culture substrata. The data supported the view that the use of phosphor-screen autoradiography was a valid method for detecting cell attachment, and it gave equivalent results to the colorimetric assay. Furthermore, a comparison between phosphor-screen autoradiography and a dye-staining method showed that this technique can be used as a means of quantifying cellular expansion over surfaces.

Autoradiography↗

PubMed1995

Adsorption of fibronectin and vitronectin onto Primaria and tissue culture polystyrene and relationship to the mechanism of initial attachment of human vein endothelial cells and BHK-21 fibroblasts.

The two cell culture substrata, tissue culture polystyrene (TCPS) and Primaria, were compared in order to determine whether a nitrogen-containing surface such as Primaria attracts cells by a different mechanism to an oxygen-containing surface (TCPS). The amounts of vitronectin (Vn) and fibronectin (Fn) which adsorb from the fetal bovine serum (FBS) component of the culture medium onto Primaria and TCPS were determined. Primaria adsorbed two- to threefold more Fn than TCPS, but adsorbed similar amounts of Vn from medium containing FBS. The Fn and Vn binding sites on Primaria were distinct, as adsorption was non-competitive between these two proteins. The amounts of Fn and Vn that adsorbed onto the two surfaces were compared to the concentration dependence of the cell attachment activities of Fn and Vn. Whereas the amounts of Fn which adsorbed onto TCPS were suboptimal for cell attachment, Primaria adsorbed an Fn surface density that was supraoptimal for attachment of human vein endothelial cells and BHK-21 fibroblasts. We conclude that Primaria differs from TCPS in that both Fn and Vn mediate initial cell attachment to Primaria when the culture medium contains FBS, whereas cell attachment to TCPS is dependent upon Vn.

Adsorption↗

PubMed1995

Role of the heparin binding domain of fibronectin in attachment and spreading of human bone-derived cells.

Human bone-derived cells are known to attach and spread on surfaces which have been precoated with fibronectin, but the contributions made by specific domains of the molecule have not yet been defined. Here we refer to the osteoblast-like cells as human bone cells. We have determined the relevance of separate regions of fibronectin, particularly the heparin-binding region, for the initial attachment and spreading of these cells. Human bone cells attached to fragments from each of the cell- and heparin-binding regions of fibronectin, but failed to attach to a fragment from the gelatin-binding region. Bovine corneal epithelial cells, which were included as an example of an alternative primary cell strain, attached to the cell-binding fragment but showed no specific short-term attachment to the heparin or gelatin-binding fragments. Monoclonal antibody MAb17, which binds to the cell binding region of fibronectin, partially inhibited the attachment of both human bone cells and corneal epithelial cells to intact fibronectin when present at 50 micrograms/ml and reduced human bone cell attachment to the cell-binding region fragment of fibronectin. Monoclonal antibody, MAb 32, which binds to the heparin-binding region of fibronectin, failed to inhibit attachment of the human bone cells to fibronectin but reduced the attachment of these cells to the heparin-binding region fragment. Heparin and chondroitin sulphate were able to inhibit human bone cell attachment to the heparin-binding fragment of fibronectin but had no effect on their attachment to intact fibronectin or the cell-binding region of fibronectin. Immunofluorescent staining and confocal microscopy showed extensive spreading and actin filament formation when human bone cells were cultured on intact fibronectin. Cells cultured on the heparin-binding fragment showed only minimal spreading coinciding with less extensive actin filament organisation. On the cell-binding fragment of fibronectin more spreading was seen than on the heparin-binding fragment but it was not as extensive as on intact fibronectin. Taken together, these data suggest that human bone cells, unlike bovine corneal epithelial cells, have an attachment mechanism for the heparin-binding region of fibronectin. Attachment to this region is probably mediated by cell surface proteoglycans. However, interaction with the cell-binding domain is required for effective cell spreading of human bone cells on fibronectin during the first 90 minutes after seeding into culture.

Actin Cytoskeleton↗

PubMed1994

Modulation of rate at which serotonin-induced contraction decays in guinea pig trachea.

Stimulation of the type 2 serotonin (5-HT2) receptor in guinea pig trachea with 5-HT results in a contraction that decays in the continued presence of 5-HT. The decay of the 5-HT contraction has been proposed to be dependent on 5-HT2 receptor activation and to reflect desensitization of the receptor. The characteristics of the decay of the 5-HT contraction may also be dependent on other properties of the tissue. The effects of modulation of biochemical pathways implicated in airway smooth muscle contraction on the 5-HT contraction in isolated guinea pig trachea were determined with the use of a kinetic approach we developed previously. Decay of the 5-HT contraction was inhibited by cooling, increased by forskolin, 3-isobutylmethyl-1-xanthine, and 8-bromoadenosine 3',5'-cyclic monophosphate, and unaffected by staurosporine, H-7, H-8, phorbol 12,13-dibutyrate, and by inhibitors of the three major pathways of arachidonic metabolism. The results suggest that decay of the 5-HT contraction in guinea pig trachea is dependent on both the receptor and the biochemical state of the tissue.

Adenylyl Cyclases↗

PubMed1994

Roles of serum vitronectin and fibronectin in initial attachment of human vein endothelial cells and dermal fibroblasts on oxygen- and nitrogen-containing surfaces made by radiofrequency plasmas.

Fluoropolymers modified by plasma modification were studied for their suitability as surfaces for the adhesion of cells. We compared films made by plasma modification of fluoroethylenepropylene (FEP) using nitrogen-containing gases (ammonia or dimethyl acetamide) with films deposited using oxygen-containing monomers (methanol, methyl methacrylate or sequential treatment with toluene then water). The surfaces were compared for the attachment and spreading of human vein endothelial cells and human dermal fibroblasts. The initial attachment and spreading of cultured fibroblasts and endothelial cells onto films deposited using nitrogen-containing gases were equivalent to that onto films deposited using oxygen-containing monomers, but there were some differences in the mechanism of attachment. With films deposited using oxygen-containing monomers, the initial attachment and spreading of endothelial cells failed when the medium contained 15% (v/v) serum from which both fibronectin (Fn) and vitronectin (Vn) had been removed. Similarly, initial attachment and spreading of endothelial cells onto films deposited using oxygen-containing monomers were reduced by 62-86% when the cells were seeded in medium containing Vn-depleted serum (which contained Fn). Endothelial cells attached and spread onto films made using oxygen-containing monomers, when seeded in medium containing Fn-depleted serum (which contained Vn). On films deposited using nitrogen-containing gases, the adhesion of endothelial cells was only slightly reduced in Vn-depleted medium (as compared to attachment in medium containing unmodified serum). Furthermore, surfaces which had incorporated nitrogen were more effective than were oxygen-containing films in adsorbing sufficient serum Fn as to promote endothelial cell attachment. Similar results were seen for the attachment and spreading of fibroblasts as for the endothelial cells. For fibroblasts, attachment and spreading onto oxygen-containing films and onto nitrogen-containing films were not simply dependent upon either the Vn content or the Fn content of the medium. Maximal attachment and spreading of fibroblasts were, however, dependent upon adsorption of both serum Vn and Fn.

Blood Proteins↗

PubMed1993

Polystyrene chemistry affects vitronectin activity: an explanation for cell attachment to tissue culture polystyrene but not to unmodified polystyrene.

Tissue culture polystyrene (TCPS) supports good attachment of adherent cells whereas unmodified polystyrene (PS) does not, but the mechanism of this difference is not well characterized. We have compared TCPS and PS for the amounts of vitronectin (Vn) and fibronectin (Fn) which adsorb from the fetal bovine serum (FBS) component of the culture medium. The significance of the amounts of Vn and Fn which adsorbed onto TCPS and PS was determined by reference to the concentration dependence of the cell attachment activity of Vn and Fn when adsorbed onto TCPS and PS, assayed using human vein endothelial cells and BHK-21 fibroblasts. The amount of Vn which adsorbed onto TCPS from medium containing 3-30% (v/v) FBS was supraoptimal for the attachment of endothelial cells and fibroblasts. On PS, the amount of Vn which adsorbed from this medium was less than for TCPS and was suboptimal for cell attachment. Higher levels of Fn adsorbed onto TCPS than to PS, but even the amounts of Fn which adsorbed onto TCPS were suboptimal for cell attachment. We propose that the principal mechanistic difference between TCPS and PS for the initial attachment and spreading of cells is that more Vn adsorbs onto TCPS from the serum component of the culture medium.

Adsorption↗

PubMed1993

Attachment of human bone cells to tissue culture polystyrene and to unmodified polystyrene: the effect of surface chemistry upon initial cell attachment.

Cell culture studies have often been used in the determination of the suitability of biomaterials as surfaces for the attachment and growth of cells. For such studies of surfaces for potential use in bone implants, cells derived from bone may be maintained in culture on tissue culture polystyrene (TCPS). We have determined the contribution that serum fibronectin (FN) or vitronectin (VN) make to the attachment and spreading of cells cultured from explanted human bone (bone-derived cells) during the first 90 min following seeding on culture surfaces. The attachment of bone-derived cells to TCPS was simulated two-fold by the addition of 10% (v/v) fetal bovine serum (FBS) to the seeding culture medium. The roles of FN and VN were determined by selective removal of the FN or VN from the FBS prior to addition to the culture medium. FBS from which the VN had been removed did not have this stimulatory activity. In contrast, the attachment of bone-derived cells onto TCPS from medium containing FN-depleted serum (which contained VN) was the same as when intact FBS was used. There was incomplete attachment of bone-derived cells (27% of cells) when seeded in medium containing FBS depleted of both VN and FN. Our results show that for human bone-derived cells, the attachment onto TCPS of cells planted in medium containing FBS during the first 90 min of culture is principally as a result of adsorption onto the surface of serum VN. As unmodified polystyrene (PS) has also been used previously as a model biomaterial surface, PS was compared to TCPS for attachment of the bone-derived cells. Attachment of bone-derived cells to TCPS was twice that onto PS, both when the medium was serum-free and when it contained FBS. Bone-derived cells attached to TCPS or PS onto which purified VN or FN had been precoated, with VN adsorbed onto PS being as effective as was VN adsorbed onto TCPS. With FN, there was an effect of the polystyrene surface chemistry which was evident in that suboptimal concentrations of FN had a slightly higher potency when adsorbed onto TCPS than did the same concentrations of FN coated onto PS. When preadsorbed onto TCPS, the potency of FN for attachment of bone-derived cells was at least equal to that of VN.

Bone and Bones↗

PubMed1993

Effects of polystyrene surface chemistry on the biological activity of solid phase fibronectin and vitronectin, analysed with monoclonal antibodies.

The conformation and biological activities of fibronectin (FN) and vitronectin (VN) coated on different plastic surfaces were investigated using cell adhesion and a panel of domain-specific monoclonal antibodies (mAbs). The adhesion of BHK fibroblasts was markedly better on FN coated on hydrophilic tissue culture polystyrene (TCPS) than on hydrophobic, untreated polystyrene (PS). mAbs A17 and 3E3, which inhibit the binding of BHK cells to the RGD-containing sequence within the cell binding region of FN, also bound preferentially to FN on TCPS. In contrast, two anti-FN mAbs, which have no effect on cell adhesion (A35 and A3), bound preferentially to the conformation of FN on the more hydrophobic PS. Mouse melanoma cells utilise an additional cell-binding site in the Hep II domain of FN and their preference for FN coated on TCPS was less marked than that of BHK cells. This reduced preference was again mimicked by the binding of a mAb, A32, which inhibits the binding of B16 cells to the Hep II domain of FN. In contrast, BHK cell adhesion to VN did not display a preference for TCPS over PS. The cell-binding activity of adsorbed VN was matched by the binding of a cell adhesion-inhibitory mAb, A18, which, unlike mAbs A17 and A32, displayed slightly increased binding to VN coated on PS, rather than TCPS. When the denaturating effect of coating FN and VN to PS in the presence of urea was investigated, similar correlations between BHK cell adhesion and the binding of inhibitory mAbs were observed. Urea treatment of FN significantly reduced both BHK cell adhesion and the binding of both cell adhesion-inhibitory mAbs, whereas the binding of A35 and A3 was unaffected. There was no significant effect of urea treatment of VN upon either BHK cell adhesion or mAb binding. A larger panel of anti-FN mAbs was used, together with the anti-VN mAbs, to determine whether there were differences in mAb recognition of FN and VN adsorbed on three different brands of TCPS. The mAbs segregated into four reactivity patterns, of which A17, A32, A35 and A18 respectively were representative. Significant differences were observed in mAb recognition of FN and VN adsorbed to different brands of TCPS. These may reflect differences in the ability of these surfaces to support optimal growth of different cell types. The effect of divalent cations upon adsorbed FN and VN was also investigated.(ABSTRACT TRUNCATED AT 400 WORDS)

Adsorption↗