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Biomedical subjects

E Ruoslahti

Publications and source records attributed to E Ruoslahti.

At least 307 records · Page 17Linked to original sources
PubMed1976

Isolation from human gastric juice of an antigen closely related to the carcinoembryonic antigen.

A carcinoembryonic antigen-like antigen(s) (CELIA) was isolated from normal human gastric jucie by immunoadsorbents and gel chromatography. The isolated CELIA reacted identically to CEA in immunodiffusion testa against anti-CEA and anti-CELIA. Other experiments suggested subtle differences between CELIA and CEA. Two out of six CELIA preparations tested in immunodiffusion did not react in a completely identical manner with CEA.In gel filtration, CELIA eluted slightly after CEA. Absorption of anti-CEA with CELIA resulted in antisera with greatly reduced reactivity to CELIA, but retained anti-CEA activity. Such antisera may be helpful in attempts to increase the cancer specificity of the CEA test.

Antigens↗
PubMed1976

Congenital nephrotic syndrome: prenatal diagnosis and genetic counselling by estimation of aminotic-fluid and maternal serum alpha-fetoprotein.

Nine families in which a previous child had had congenital nephrotic syndrome (C.N.) sought genetic counselling and possible antenatal diagnosis of fetal disease. Maternal serum and amniotic-fluid alpha-fetoprotein (A.F.P.) assays were carried out between the 15th and 20th weeks of subsequent pregnancies. Seven women in whom A.F.P. concentrations were normal chose to continue pregnancy, and they were all delivered of a healthy child. Markedly raised amniotic A.F.P. concentrations were found in two cases; in one of these cases maternal serum-A.F.P. was also raised. These pregnancies were terminated, and electron microscopy of the fetal kidneys showed evidence of C.N. in the fetus--i.e., loss of foot processes and an increase in the mesangial matrix of the glomeruli. The outcomes of these at-risk pregnancies indicate that prenatal diagnosis and genetic counselling are possible in families with a history of C.N. The results also stress the importance of carefully examining fetal kidneys whenever amniotic-fluid A.F.P. concentration is raised in the absence of apparent malformations.

Amniotic Fluid↗
PubMed1976

Monkey antisera with increased specificity to carcino-embryonic antigen (CEA).

Three Macaca irus monkeys were immunized with purified human CEA. One received unmodified CEA and two were immunized with haptenated (4-hydroxy-5-iodo-3-nitrophenyl acetyl) CEA. All three monkeys formed precipitating antibodies to CEA. The antisera did not precipitate the CEA-related normal glycoprotein antigen (NCA). In contrast, CEA-immunized rabbits, sheep and goats invariably form antibodies against NCA. Radio-immunoassays showed the monkey antisera to contain trace amounts of antibodies to NCA but the titers were about 10-1,000 times lower than those in rabbit and sheep sera with comparable anti-CEA titers. These results show that monkeys produce antibodies against CEA, but respond weakly to a normal, CEA-related antigen. The weak response to NCA suggests that monkeys may possess an NCA-related antigen. Antisera lacking reactivity to normal CEA-related antigens may be helpful in establishing a more specific diagnostic test for CEA.

Animals↗
PubMed1976

Fibroblast surface antigen (SF): the external glycoprotein lost in proteolytic stimulation and maligant transfromation.

It was previously shown that the fibroblast surface antigen (SF antigen, SFA) is composed of polypeptides of high molecular weight 210,000 (SF210) and 145,000 (SF145) and that both of these decrease in quantity after transformation of the fibroblasts by Rous sarcoma virus (RSV). The present experiments show that SF210 is a glycoprotein. It is accessible to surface labelling by lactoperoxidase catalyzed iodination. The SF210 molecule is highly susceptible to trypsin on cell surface. Anti-SFA antibodies specifically precipitated the surface labelled polypeptide. The lactoperoxidase iodinated SF210 polypeptide was greatly reduced in cells transformed by RSV. It is concluded from these studies that the large external transformation sensitive (LETS) protein detected by other workers is the same molecule as SF210. Part of the label of surface iodinated fibroblasts did not enter the polyacrylamide gels. This high molecular weight material is also susceptible to trypsin treatment and decreases in quantity after transformation by RSV. The data suggest that it may be antigenically related to SF protein. Treatment of surface of 35S-methionine-labelled cultures with trypsin in concentrations able to initiate proliferation of density-inhibited cells rapidly released SF210 from fibroblast surface. A single high molecular weight polypeptide (mol. wt about 200,000, SF200) was detected in the culture medium. SF210 may thus be a major target molecule of trypsin action. Treatment of cultures with insulin that also stimulated the fibroblasts to initiate proliferation did not result in any detectable alteration in the external glycoprotein SF210. It is concluded that although release of SF210 may be a sufficient trigger to stimulate proliferation in stationary cells, this molecule appears not to be directly involved in initiation of fibroblast proliferation from the G1 (or G0) phase of the cell cycle.

Animals↗
PubMed1976

A common cell-type specific surface antigen in cultured human glial cells and fibroblasts: loss in malignant cells.

Fibroblast surface antigen (SFA) is a high molecular weight protein antigen, first shown on the surface of cultured fibroblasts in fibrillar structures. It is shed to the extracellular medium and also present in the circulation (serum and plasma). Fibroblasts transformed by tumor viruses produce SFA but do not retain it on cell surface. In this report we show that SFA is also present in cultured nonestablished astroglial cells. The glial and fibroblast SFAs are immunologically indistinguishable. Glial cells (three different nonestablished lines) contain more SFA per milligram cellular protein than fibroblasts. SFA was located on cell surface in fibrillar striae that frequently extended out from the cell body. Fluorescence was also found intracellularly in the cytoplasm. Malignant gliomas (astrocytomas) established to grow in culture from human tumor material produced SFA into the growth medium but had very little (lines U-105 MG and U-343 MG) or no detectable (lines U-118 MG, U-251 MG, and U-343 MG-a) cell surface SFA. In cultures of the glioma cells many cells, in particular those that appeared to be in the telophase stage, stained strongly positive for intracellular cytoplasmic SFA. These data demonstrate that similar to fibroblasts transformed experimentally by oncogenic viruses, cells grown from naturally occurring human tumors (glioblastomas) produce SFA but lose ability to retain it on cell surface.

Antibodies↗
PubMed1976

Fibroblast surface antigen (SF): molecular properties, distribution in vitro and in vivo, and altered expression in transformed cells.

We have recently described a cell type-specific surface (SF) antigen that is deleted in chick fibroblasts transformed by Rous sarcoma virus, SF antigen is a major surface component and makes up about 0.5% of the total protein on normal cultured fibroblasts. The antigen is shed from normal cells and is present in circulation (serum, plasma), and in vivo, also, in tissue boundary membranes. The molecular equivalents of both cellular and serum SF antigen are distinct, large polypeptides, one of which (SF210, MW 210,000) is glycosylated and, on the cell surface, highly susceptible to proteases and accessible to surface iodination. Immunofluorescence and scanning electron microscopy have indicated that the antigen is located in fibrillar structures of the cell surface, membrane ridges, and processes. Human SF antigen is present in human fibroblasts and in human serum. We have recently shown that human SF antigen is identical to what has been known as the "cold-insoluble globulin" and that it shows affinity toward fibrin and fibrinogen. Our results also indicate that loss of the transformation-sensitive surface proteins is due not to loss of synthesis but to lack of insertion of the protein in the neoplastic cell surface. Both normal and transformed cells produce the SF antigen, but the latter do not retain it in the cell surface. The loss of SF antigen, a major cell surface component, from malignant cells creates an impressive difference between the surface properties of normal and malignant cells. The possible significance of SF antigen to the integrity of the normal membrane and its interaction to surrounding structures is discussed.

Animals↗
PubMed1976

A monkey antigen crossreacting with carcinoembryonic antigen, CEA.

Normal monkey tissues were found to contain an antigen which crossreacts immunologically with the carcinoembryonic antigen (CEA) of the human digestive tract. The monkey antigen reacted with complete or partial identity to the normal crossreacting antigen (NCA) in humans when tested in immunodiffusion against anti-CEA or anti-NCA. Extracts of monkey tissues inhibited in radioimmunoassays measuring human NCA. It is possible that monkey foetuses and colonic tumours contain CEA.

Animals↗
PubMed1976

Immunological crossreaction between alpha-fetoprotein and albumin.

Alpha-fetoprotein (AFP), a fetal protein associated with certain tumors, and serum albumin did not corssreact immunologically in native form. Unfolding of their polypeptide chains by reduction of the disulfide bonds followed by carboxamidomethylation produced derivatives with immunochemical properties different from those of the native proteins. Precipitating reactions and radioimmunoassays preformed with antibodies to such unfolded derivatives showed strong crossreactions between albumin and AFP. These assays were found to lack species specificity: AFPs and albumins from different species were equally active. Several other proteins unrelated to AFP or albumin did not react or reacted much less in these assays. These results support the conclusions derived from recent sequence data that AFP and albumin are structurally related and have a common ancestral gene.

Alkylation↗
PubMed1976

Alpha-fetoprotein.

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Abortion, Spontaneous↗
PubMed1975

Fibroblast surface antigen produced but not retained by virus-transformed human cells.

Normal human fibroblasts contain a cell type-specific glycoprotein antigen (SF) that is known to be slowly shed into the medium and to be present also in human serum. Immunofluorescence with anti-SF antibodies showed that SF antigen has a highly nonrandom fibrillar distribution in surface of normal fibroblasts. Simian virus 40-transformed fibroblasts also produced the SF antigen, as shown by radioimmunoassay or immunodiffusion tests, but it was not retained by the surface of these cells. This creates a major difference between the surfaces of normal and malignant cells.

Antigens↗
PubMed1975

Distribution of fibroblast surface antigen in the developing chick embryo.

Fibroblast surface (SE) antigen is present in fibrillar surface structures of cultured normal fibroblasts, shed to the extracellular medium, and is also found in circulation (serum and plasma). Malignant fibroblasts (transformed by viruses) do not express SF antigen on the cell surface. In this study the in vivo differentiation and distribution of SF antigen has been investigated in the developing chick embryo using cryostat sections and immunofluorescence. The major findings were: (a) SF antigen was detectable in the loose connective tissue of very early (2-to 3-day old) embryos. (b) Condensation of SF antigen was seen in various boundary membranes such as the glomerular and tubular basement membranes of the kidney, the boundary membranes of the notochord, yolk sac, and vitelline membranes and liver sinusoids. (c) SF antigen was found to be cell-type specific. It was seen as a fibrillar network in the loose connective tissue of different organs but not in the parenchymal cells. It was not found in muscle cells at any stage of development. (d) The antigen was present in the undifferentiated mesenchymal cells of the kidney; but not found after their development into epithelial cells of the secretory tubules. (e) Both in vivo and in fibroblast cultures SF antigen was distributed as a fibrillar network. These data indicate that SF antigen is a "differentiation antigen" restricted to certain cells of mesenchymal origin and character, and that is accumulates in the connective tissue during embryogenesis.

Animals↗
PubMed1975

Interaction of soluble fibroblast surface antigen with fribrinogen and fibrin.

A cell-type specific glycoprotein antigen (SFA) from fibroblast surface appears in human plasma and serum. The amount of SFA in serum was reduced if the blood coagulation clot was removed at a low temperature. SFA could be bound to Sepharose-conjugated fibrinogen and to fibrin powder at 0 degrees C and was subsequently released when the temperature was elevated to plus 37 degrees C. This procedure resulted in a 10-fold enrichment of SFA relative to other serum proteins. SFA was found to be concentrated in the cryoprecipitate fraction of human plasma and was copurified with the cold insoluble globulin (CIG) with procedures published for the purification of the latter component. SFA/CIG is not soluble at low temperatures as such and its appearance in the cryoprecipitate fraction of plasma is likely to be due to its affinity to cryofibrinogen evident from these experiments. The biological significance of the interaction of fibroblast surface SFA moleculres with fibrin(ogen) is not known.

Antigens↗
PubMed1975

Polypeptides of a glycoprotein antigen (SF) present in serum and surface of normal but not of transformed chicken fibroblasts.

A protein immunologically identical to a glycoprotein antigen from fibroblast plasma membrane (SF antigen complex) is present in chicken serum. This antigen disappears from cells transformed with tumor viruses. The antigen solubilized from fibroblasts using urea and detergents, and the serum component both gave a molecular weight of about 2-10(5) as estimated by gel filtration on Sepharose 4B. Ultracentrifugation in 5-20% sucrose gradients gave a value of 7-8 S for the antigen from both sources. Isolation of antigen from serum and fibroblasts extracts was achieved using immunochemical techniques. Analysis of the polypeptide chains of the cellular antigen by electrophoresis in the presence of sodium dodecylsulphate, disclosed three major components at molecular weights 210 000 and 145 000 and 45 000. The two high molecular weight bands were identified in electrophoretograms of whole cell extracts by absorption to and subsequent elution from immunoadsorbents. The 45 000-molecular weight components comigrated with purified actin in electrophoresis. After short pulses of (35S) methionine the high molecular weight polypeptides, the 145 000-molecular weight component in particular, were among the most prominent radioactive bands from whole cell extracts indicating that SF antigen has a rapid turn-over. The antigen isolated from serum showed a polypeptide composition similar to the one from cells except the 45 000-molecular weight component was not detectable.

Animals↗