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T Dalianis

Publications and source records attributed to T Dalianis.

At least 55 records · Page 3Linked to original sources
PubMed1988

Immunization against the polyoma tumor-specific transplantation antigen (TSTA) with polyoma T-antigens.

The relationship between the polyoma virus tumor-specific transplantation antigen (TSTA) and 2 of the virus proteins coded from the early region of polyomavirus was investigated. Mice were immunized with small T antigen and a truncated mutant of middle T antigen, both purified from genetically engineered Escherichia coli. The 2 proteins induced protective immunity against polyomavirus-induced tumors, but not against non-polyoma tumors, indicating that one or more of the polyoma T antigens are directly involved in a TSTA function.

Animals↗
PubMed1988

A polyomavirus tumor-specific transplantation antigen (TSTA) epitope is situated within the N-terminal amino acid sequence common to middle and small T-antigens.

An MT cDNA-transformed rat cell line (2.8), that contains only the polyoma middle T-antigen and expresses polyoma TSTA, can be rejected in rats immunized with 1837 cells that carry a host range (A185 hr-t), mutant which expresses a full-length large T-antigen, and nonfunctional N-terminal fragments of small and middle T. This shows that at least one polyoma TSTA epitope is situated in the 113 amino acid N-terminal region, which is common to middle and small T-antigens.

Amino Acid Sequence↗
PubMed1987

Studies on the polyoma tumor-specific transplantation antigen (TSTA): selection and characterization of TSTA-negative segregants from somatic hybrids.

Two polyoma-TSTA-negative variants were selected independently from a polyoma fibrosarcoma/Moloney lymphoma somatic hybrid, by repeated passages in polyoma-virus-preimmunized mice. One of the variants had lost all its polyoma DNA, while the other only retained a deleted piece of its integrated polyoma DNA. In contrast to the parental hybrid clone, none of the variants produced detectable amounts of T-antigens. This finding indicates that a detectable expression of the products of the polyoma virus early genome, the T-antigens, is important either directly or indirectly for the expression of TSTA.

Animals↗
PubMed1986

Detection of a polyoma virus-induced tumor-associated membrane antigen in mouse cells by the macrophage migration inhibition test.

Soluble membrane fractions derived from polyoma tumor cells trigger lymphocytes, derived from polyoma-immunized animals, but not from nonimmunized controls, to release the lymphokine, macrophage migration-inhibitory factor. The reaction can be blocked by sera from polyoma-bearing animals. Absorption of these sera with polyoma cells, but not with nonpolyoma cell lines, abrogates this activity. These findings suggest that there is a polyoma virus-induced membrane component that can induce polyoma-specific macrophage migration inhibition.

Animals↗
PubMed1984

Studies on the polyoma-virus-induced tumor-specific transplantation antigen (TSTA)--does middle or large T-antigen play a role?

Mice and rats could be immunized against the polyoma-virus-induced tumor-specific transplantation antigen (TSTA) by repeated inoculation of frozen or irradiated cells of an MT-cDNA-transformed rat cell line (2.8) that contains only the polyoma middle T-antigen, or by cells that carried a host range mutant and expressed a full-length large T-antigen, but only non-functional N-terminal fragments of small and middle T. This shows that neither large T nor an intact middle T is necessary to elicit a polyoma tumor-specific graft rejection response. Either one of them is sufficient by itself.

Animals↗
PubMed1984

Detection of mutant-specific responses by macrophage migration inhibition reactions induced by wild-type and mutant polyoma viruses and polyoma virus-infected cells.

Macrophage migration inhibition responses of mice immunized with mutant polyoma viruses or with cells transformed and/or infected by them have been studied. The macrophage migration inhibition reaction revealed individual differences. In several cases, mice immunized with a mutant virus responded preferentially or exclusively to extracts of cells transformed or infected with the corresponding mutant. Moreover, in the macrophage migration inhibition test, mutant viruses were usually less immunogenic than were the corresponding transformed-infected cells.

Animals↗
PubMed1983

Studies on the possible chemical, immunochemical and morphological differences at the cell surfaces of immunosensitive and immunoresistant, Moloney virus-induced, lymphoma cell-lines.

Comparison was made of several cell-surface parameters in the immunosensitive, Moloney virus-induced, mouse lymphoma, YAC, and its immunoresistant variant, YACIR. The characteristics of the two cell lines appeared to be similar by most of the criteria employed. The poly(acrylamide)-gel electrophoresis (with sodium dodecyl sulfate) patterns, after staining with Coomassie Brilliant Blue, of detergent-solubilized materials, appeared to be identical. After elution from a gel filtration column, no major differences were observed in the protein profiles of material cleaved from viable cells by proteolysis. Scanning and transmission electron microscopy revealed no major differences between the YAC and YACIR cells. The concentration of the lectins, Ricinus communis agglutinin, concanavalin A, wheat-germ agglutinin, and Solanum tuberosum (potato) agglutinin, required to agglutinate viable cells of the two lines were not significantly different. Neither cell was agglutinated by the lectins from Dolichos biflorus or Vicia graminea. Significant differences were, however, observed in the concentrations of lectin from Arachis hypogaea (peanut) needed to agglutinate the two cells. Although similar amounts (184-188 micrograms/10(9) cells) of sialic acid were released from viable cells by neuraminidase (V. cholerae), striking differences were observed in the composition of this material: 48% of N-glycolylneuraminic acid for YAC and 15% for YACIR. The remainder was N-acetylneuraminic acid for each cell line.

Agglutination↗
PubMed1983

Antibodies against a nonapeptide of polyomavirus middle T antigen: cross-reaction with a cellular protein(s).

Antibodies were raised against the sequence Glu-Glu-Glu-Glu-Tyr-Met-Pro-Met -Glu, which represents a part of the middle T antigen of polyomavirus that is considered to be important in inducing the phenotype of transformed cells. The antibodies reacted with native as well as denatured middle T antigens. In addition, the antibodies immunoprecipitated a cellular protein with an apparent molecular weight of 130,000 (130K) from mouse and rat cells. In some cases, a 33K protein was also immunoprecipitated. Immunoprecipitation of middle T antigen as well as 130K and 33K proteins was blocked by the peptide. The antibodies labeled microfilaments of untransformed mouse, rat, human, and chicken cells by immunofluorescence. This labeling was also blocked by the peptide. The labeling pattern and distribution under a variety of conditions were indistinguishable from those of anti-actin antibodies, although no evidence has been obtained to indicate that the anti-peptide antibodies react with actin. The 130K protein migrated in sodium dodecyl sulfate-polyacrylamide gel electrophoresis slightly slower than chicken gizzard vinculin (130K) and slightly faster than myosin light-chain kinase of chicken smooth muscle (130K). Neither of these proteins absorbed the anti-peptide antibodies. The 33K protein does not seem to be tropomyosin (32K to 40K).

Animals↗
PubMed1983

Physicochemical and morphological characterization of a new allotransplantable mammary carcinoma ascites subline, TA3-St/ticol/-A.

The TA3-St/ticol ascites cell (I), immunoselected from the strain-specific TA3-St mammary carcinoma ascites cell of the strain A mouse for decreased H-2a antibody-binding capacity, underwent a spontaneous transition in vivo to a new cell line, TA3-St/ticol/-A (II). Line II was more allotransplantable than was the parental line (line I), and its absorptive capacity for anti-H-2a antibody was manyfold less than line I. Disruption of line II cells by lyophilization did not increase the absorptive capacity, in contrast to its marked enhancement in the TA3-Ha ascites cell under similar conditions. An explanation for the enhanced allotransplantability of line II may be related to either a loss of H-2a antigens or altered macromolecular structures at the cell surface: sialic acid, consisting of 93% N-glycolylneuraminic acid for line II and 9% for line I; altered chemical structures of cell surface glycoproteins, particularly a high-molecular-weight glycoprotein present in much greater proportion in line II than in line I; a macromolecular complex released by a protease from line I, but not line II; and I being agglutinable by concanavalin A, but not line II. Electron microscopy showed line II to be more pleomorphic and less rounded than was line I. Under high-resolution electron microscopy, the cell surfaces of both allotransplantable cells, lines II and I, exhibited thin filamentous material, material not observed at the surface of the nonallotransplantable TA3-St ascites cell.

Animals↗
PubMed1983

Cell surface characteristics of an allotransplantable TA3 ascites subline resulting from a process of immunoselection.

Comparison of the cell surface characteristics of the parental strain-specific TA3-St ascites cell (I) of the strain A mouse and the more allotransplantable TA3-St/ticol ascites cell (II), immunoselected for reduced absorption of anti-H-2a antibody from Cell I, revealed the following. Cell II, like Cell I, possessed no detectable epiglycanin at its surface, as neither cell absorbed more than 0.5% as much of the antiepiglycanin antibody as was absorbed by the epiglycanin-containing allotransplantable TA3-Ha ascites cell. Tritium-labeled glycoproteins, with polyacrylamide slab gel electrophoresis with sodium dodecyl sulfate and with isoelectric focusing of detergent-treated cells, exhibited marked quantitative differences, but qualitative differences were not established. Glycopeptides cleaved from each cell by proteolysis and fractionated by gel filtration gave similar elution profiles, and the column fractions possessed similar carbohydrate and amino acid compositions. Less sialic acid (170 micrograms/10(9) cells) was removed by neuraminidase from Cell II than from Cell I (270 micrograms/10(9) cells), and the compositions (9% N-glycolylneuraminic acid for Cell II and 20% for Cell I) were different. Transmission and scanning electron microscopy showed rough irregular folds and ridges on the surfaces of each cell, but Cell II appeared more pleomorphic and less rounded than did Cell I. High-resolution transmission electron microscopy showed filamentous material at the surface of Cell II, but not at the surface of Cell I.

Amino Acids↗
PubMed1982

Immunization against the polyoma virus-induced tumor-specific transplantation antigen by early region mutants of the virus.

To investigate the relation between the polyoma tumor-specific transplantation antigen and the virus-coded proteins, mice were immunized by inoculation of a variety of viable polyoma virus mutants and then challenged with polyoma virus-induced tumors. Two classes of early region mutants were used. One class produces a normal small T-antigen and truncated middle and large T-antigens. The second class (hr-t mutants) forms a normal large T-antigen together with N-terminal fragments of small and middle T-antigens. All mutants, transforming as well as nontransforming, induced protection against polyoma virus tumors. However, there were quantitive differences between the mutants. The finding that an hr-t mutant could induce tumor rejection suggests that full-length middle and small T-antigens are not necessary for the induction of this response. Since intact middle T-antigen is the only virus-coded protein known to associate with the plasma membrane, the possibility must be considered that the polyoma virus tumor-specific transplantation antigen consists of cellular components.

Animals↗
PubMed1981

Correlation of glycosphingolipids and sialic acid in YAC-1 lymphoma variants with their sensitivity to natural killer-cell-mediated lysis.

Sialoglycoconjugates and glycosphingolipids were quantitated in a series of variants derived from the YAC-1 lymphoma, known to be highly sensitive to natural killer (NK)-cell-mediated lysis. The variants, which had widely diverging sensitivities to NK cells, were obtained by a number of methods, including selection in the presence of NK cells, antibody to H-2, or antibody to the murine leukemia-virus-induced antigen, and by fusion of sensitive cells with an NK-resistant cell line, A9HT. The sensitivities of these cells to NK-cell-mediated lysis did not correlate with their sensitivities to anti-H-2a cytotoxic T cells. While no correlation could be made between the NK-sensitivity of these variants and their total cellular sialic acid, a statistically significant inverse correlation was observed between the levels of percentage neuraminidase releasable surface sialic acid of total labelled sialyl components and sensitivity to NK cells. This correlation with cell surface sialic acid was observed with either endogenous or lymphocytic choriomeningitis virus-induced activated NK cells as effectors. Neuraminidase treatment of insensitive target cells caused a moderate increase in sensitivity but failed to render the resistant targets as sensitive as YAC-1. Analysis of glycosphingolipids among the variants revealed a strong positive correlation between the total cell neutral glycolipid with chromatographic migration of asialo-GM2 and sensitivity to endogenous or activated NK-cell-mediated lysis. Significant correlations were not found with any other neutral glycolipids. However, ganglioside homologues with chromatographic mobility of GM1, GD1a, GD1b, And GT also showed a positive correlation with both endogenous and activated NK-cell-mediated lysis. The ratio of asialo-GM2 to GM2 had a highly significant positive correlation with sensitivity. These correlative results suggest that asialo-GM2 and certain gangliosides could be involved in binding or lytic events in NK cell:target cell interactions, and that high levels of sialic acid and sialylation on the surface may inhibit and/or modify such interactions. Further studies with these YAC variants should be useful for examining the biochemical bases of target cell-effector cell interactions in the NK-system.

Animals↗
PubMed1981

Implantation of mouse histocompatibility antigens into membranes of cultured tumor cells.

Membranes of murine lymphoma cells expressing H-2a antigens were isolated, purified and co-reconstituted with isolated Sendai virus envelopes according to a previously published procedure (Volsky, D.J. et al., Proc. Natl. Acad. Sci. USA 1979. 76: 5440.). The resulting hybrid H-2a/Sendai virus envelope vesicles (SH-2a vesicles) were capable of binding to and fusing with mouse lymphoma cells. The fusion resulted in the implantation of H-2a antigens into membranes of target cells, as demonstrated by the presence of serologically active antigens on cultured cells 8 and 16 h after implantation.

Animals↗
PubMed1981

Reduced humoral and cellular cytotoxic sensitivity in histocompatibility variants of the YAC (Moloney) lymphoma.

Previously we have reported that two sublines of the YAC lymphoma selected for reduced expression of H-2a and Moloney-virus determined cell-surface (MCSA) antigens are, in contrast to YAC, allotransplantable in H-2-incompatible recipients, and resistant to rejection by preimmunized semisyngeneic hosts. A third YAC variant with reduced MCSA but unchanged H-2-antigen expression, was not allotransplantable and showed only a slight decrease in its immunosensitivity in preimmunized semisyngeneic hosts in vivo. This suggested that H-2-antigen expression may be more important than MCSA expression for recognition and rejection by semisyngeneic mice. We have not tested the sublines expressing low H-2a for their in vitro sensitivity to humoral and cell-mediated lysis. - The variants were more resistant than YAC to complement lysis by anti-H-2a , anit-MCSA, anti-Thy 1.2 and antispecies sera. Absorption tests with antispecies serum indicated that the decreased cytolytic sensitivity of the variants was not related to the concentration of the relevant antigens, which was similar to that of the original YAC tumor. As expected from the low amount of H-2a the variants showed a decreased sensitivity to the killing effect of allogeneic cytotoxic T lymphocytes (CTL). They were also lysed to a lesser extent than YAC by semisyngeneic CTL, probably directed against virally determined antigens. However, they were also less sensitive to lysis by natural killer (NK) cells, although NK lysis is probably unrelated to MHC expression. In conclusion, our selection for reduced H-2-expression appears to have resulted in the isolation of variants with a generally increased resistance to various humoral and cell-mediated lytic functions.

Animals↗
PubMed1977

Column separation of viral capsid antigen (VCA)-positive cells from VCA-negative cells in an Epstein-Barr virus (EBV)-producing lymphoid line,.

Virus producing, VCA (viral capsid antigen)-positive cells could be selectively removed from Epstein-Barr virus (EBV)-carrying, virus-producer P3HR-1 cultures by two different methods of column passage. In the first, the virus-producing cells were covered with human EBV antibody and subsequently passaged through anti-human-Ig columns. In the second methods, untreated P3HR-1 cells were allowed to pass through columns of EBV receptor-positive cell lines or, as controls, EBV receptor-positive cell lines or, as controls, EBV receptor-negative cells. The majority of the VCA-positive cells were selectively removed by both techniques. The second method involves the attachment of EBV-producer cells, known to accumulate viral envelope material in their plasma membrane, to EBV receptors. In view of recent evidence indicating an association between EBV and complement receptors, human and mouse complement were tested for their ability to block this attachment. Fresh mouse and human complement regularly exerted blocking activity, whereas heat-inactivated human serum did not block. Heat-inactivated mouse serum did block occasionally, but the effect was more irregular than with fresh mouse serum. Trypsin treatment of the EBV-receptor colum abolished its ability to retain VCA-positive cells.

Antibodies↗
PubMed1977

Separation of cells with different histocompatibility (H-2) antigens by passage through cellular immunoadsorbent columns.

The anti-Ig column technique of Wigzell et al. (Scand. J. Immunol. 1972. 1:75) was adapted to the separation of mouse cells with different H-2 antigens. Fractionation was achieved by a two-step procedure: first the cells were treated with anti-H-2 sera, and thereafter passed over anti-mouse Ig columns. Antibody-coated cells were selectively retained in the anti-Ig column. The method could be applied to the separation of normal mouse lymphocytes or lymphoma cells with different H-2 antigen complexes and for the selective isolation of H-2 loss variants from a mouse carcinoma/fibroblast hybrid.

Animals↗