Showing papers on "Antigen published in 1979"
TL;DR: It is reported here that the T antigen in a line of SV40-transformed mouse cells forms an oligomeric complex with a specific cell coded protein.
Abstract: THE early region of the small DNA tumour virus, simian virus 40 (SV40), is known to code for at least two polypeptides, the t and T antigens (‘small t’ and ‘large T’) Both these polypeptides are expressed in cells transformed by the virus1–4, and the T antigen has been shown to be essential for both the initiation and maintenance of the transformed state5–9 We therefore need to know how this T protein interacts with components of the host cell in order to understand the mechanism of SV40-induced transformation We report here that the T antigen in a line of SV40-transformed mouse cells forms an oligomeric complex with a specific cell coded protein
2,400 citations
TL;DR: This paper used hybridoma monoclonal antibodies obtained after immunization of mice with rat cells to study rat cell-surface antigens present on subpopulations of rat lymphocytes.
Abstract: Xenogeneic immunizations have the advantage of detecting a wide range of antigenic determinants because many commonly occurring proteins have diverged significantly during the course of evolution and are thus antigenic in other species. The broadness of xenogeneic responses, however, means that the antisera they produce are usually complex and require extensive absorptions to make them specific for a single antigen. This problem has now been overcome by generating hybridomas producing monoclonal antibodies (Kohler & Milstein 1975). These permit dissection ofthe xenogeneic response so that large amounts of individual antibodies can be obtained, each of which recognizes only one of the determinants recognized by a broadly reactive conventional antiserum. Williams et al. (1977) used hybridoma monoclonal antibodies obtained after immunizations of mice with rat cells to study rat cell-surface antigens present on subpopulations of rat lymphocytes, i.e., differentiation antigens. Springer et al. (1978a) and Stern et al. (1978) used a similar approach to study mouse lymphocyte antigens. They prepared monoclonal antibodies by immunizing rats with mouse lymphocytes and showed that these monoclonals recognized previously undetected mouse cell surface determinants including a glycoprotein antigen that appears to be specific for macrophages (Springer et al. 1978b). Trowbridge (1978) also used rat anti-mouse immunizations to generate a monoclonal antibody against the non-polymorphic lymphocyte surface antigen T200.
1,916 citations
TL;DR: This chapter focuses on the important discovery that virus-specific cytotoxic T cells are dually specific for virus and for a self cell surface antigen encoded by the major histocompatibility complex (MHC).
Abstract: Publisher Summary This chapter focuses on the important discovery that virus-specific cytotoxic T cells are dually specific for virus and for a self cell surface antigen encoded by the major histocompatibility complex (MHC). The initial work was carried out on the lymphocytic choriomeningitis virus system but it soon became evident that the same phenomenon applied to many other viruses. In addition, the same principle has been found to hold for other antigenic systems, such as trinitrophenyl coupled to cells, minor histocompatibility antigens, and the H-Y model. Graft rejection and the need for genetically homogeneous inbred mouse strains for cancer research led to the development of transplantation immunology and immunogenetics. The result is that the gene complex coding for major transplantation antigens is one of the better understood mammalian genetic regions. Cytotoxic T-cell specificity is comparable to serological specificity. Because quantification of specificity or cross-reactivity is difficult, and because of the technical limitations of these cytotoxic T-cell assays, results are interpreted with great reservation. MHC restriction reflects the fact that the effector function of T cells is determined by the kind of Self-H recognized together with the foreign antigen on cell surfaces: K and D are receptors for lytic signals, I determinants are receptors for cell differentiation signals that are delivered antigen-specifically by T cells.
1,858 citations
TL;DR: It is concluded that SV40 infection or transformation of mouse cells stimulates the synthesis or enhances the stability of a 54K protein, which appears to be associated with SV40 T antigen in SV40-infected and -transformed cells, and is co-immunoprecipitated by hybridomas sera to SV40 large T antigen.
1,759 citations
TL;DR: Three novel nonoclonal antibodies (designed OKT1, OKT3, and OKT4) were generated against surface determinants of human peripheral T cells but differed in their reactivities with T cel- lines.
Abstract: Three novel nonoclonal antibodies (designed OKT1, OKT3, and OKT4) were generated against surface determinants of human peripheral T cells. Both OKT1 and OKT3 reacted with all human peripheral T cells and 5 to 10 percent of thymocytes but differed in their reactivities with T cel- lines. By contrast, OKT4 reacted with 55 percent of human peripheral T cells and 80 percent of thymocyted in that they did not react with normal B cells, null cells, monocytes, or granulocytes.
1,385 citations
TL;DR: Hybridoma cells which secrete colorectal carcinoma-specific antibodies have been produced and used to study the antigenic structure of these tumor cells, and several antigens with distinct molecular characteristics have been shown to exist by use of hybridoma antibodies.
Abstract: Hybridoma cells which secrete colorectal carcinoma-specific antibodies have been produced and used to study the antigenic structure of these tumor cells. Nineteen antibodies have been studied in detail, and 15 of these are colorectal carcinoma specific. Only two antibodies reactive with carcinoembryonic antigen (CEA) have been discovered and five other antibodies that react with distinct epitopes on the cell surface have been defined. Several antigens with distinct molecular characteristics have been shown to exist by use of hybridoma antibodies. Six hybridoma antibodies have been shown to mediate antibody-dependent cell-mediated cytotoxicity (ADCC).
1,353 citations
TL;DR: The ability of the hybridoma IgG to inhibit mouse FcRII was independent of the major histocompatibility complex and the monoclonal 2.4G2 IgG antigenic determinant was not present on rat, guinea pig, rabbit, or human F cR-bearing cells.
Abstract: To investigate the antigenic relationship between the macrophage and lymphocyte Fc receptors (FcR), a monoclonal antibody capable of blocking mouse macrophage Fc receptors was selected. Hybrids were formed by fusing the P3U1 mouse myeloma and spleen cells from a rat immunized with the mouse macrophage-like cell lines J774 and P388D1. The Fab fragment of the monoclonal IgG secreted by clone 2.4G2, inhibited the trypsin-resistant Fc receptor II (FcRII), which is specific for immune aggregates of mouse IgG1 and IgG2b, but had no inhibitory effect on the trypsin-sensitive Fc receptor I (FcRI), which binds monomeric IgG2a and erythrocytes coated with IgG2a. Thus, the monoclonal 2.4G2 IgG appeared to be specific for macrophage FcRII. Further evidence that the 2.4G2 IgG was directed against FcRII came from binding studies of the monoclonal antibody to J774 cells and a series of independently isolated variants which do not express FcRII. These variants of J774 bound 5% as much of the monoclonal antibody as the parent line, which bound 600,000 molecules of 2.4G2 IgG per cell. The antigenic relatedness of mouse lymphocyte FcR to mouse macrophage FcRII was demonstrated by the binding of 2.4G2 IgG to FcR-bearing lymphoid cell lines and the inhibition of the lymphocyte FcR by the monoclonal antibody. Preincubation of spleen cells and peritioneal cells with 2.3G2 IgG likewise inhibited rosette formation with ox erythrocytes coated with rabbit IgG. The ability of the hybridoma IgG to inhibit mouse FcRII was independent of the major histocompatibility complex. The 2.4G2 IgG antigenic determinant was not present on rat, guinea pig, rabbit, or human FcR-bearing cells.
1,263 citations
TL;DR: M1/70 thus defines a differentiation antigen on mononuclear phagocytes and granulocytes, the expression of which is specifically increased during monocyte maturation, the first to be described which recognizes a discrete molecule specific to phagocyte.
Abstract: We have previously described the derivation of M1/70, a hybrid myeloma line secreting monoclonal rat anti-mouse cell surface antibody (Springer, T., Galfre, G., Secher, D. S. and Milstein, C, Eur. J. Immunol. 1978. 8: 539). We have now investigated the cellular distribution of this antigen using a 125I-labeled anti-rat IgG indirect binding assay, the fluorescence-activated cell sorter, autoradiography and precipitation of cell surface molecules. Screening with a tumor cell panel showed strong reactivity with a macrophage-like line but no reactivity with B or T lymphoma lines. In normal tissues, M1/70 antigen was found to be present in small amounts on spleen and exudate granulocytes and a subpopulation of bone marrow cells, in moderate amounts on spleen and blood monocytes and expressed in much larger amounts on spleen histiocytes and peritoneal exudate macrophages. In contrast, M1/70 antigen was found to be absent from erythroid and lymphoid cells. M1/70 antibody precipitated two polypeptides of 190 000 and 105 000 mol. wt. which were present in much greater amounts on peritoneal exudate macrophages than on spleen cells. The expression on phagocytes of two other antigens identified by monoclonal antibodies M1/69 and M1/9.3 was also examined. Monocytes and granulocytes expressed large amounts of M1/69 and low amounts of M1/70 antigen, while in peritoneal exudate macrophages this pattern was dramatically reversed. M1/70 thus defines a differentiation antigen on mononuclear phagocytes and granulocytes, the expression of which is specifically increased during monocyte maturation. This antibody is the first to be described which recognizes a discrete molecule specific to phagocytes.
1,117 citations
TL;DR: Pure populations of Schwann cells are derived from dissociated cultures of neonatal rat sciatic nerve that express the S100 antigen, as shown by indirect immunofluorescence and complement fixation, and receptors for cholera toxin.
1,071 citations
TL;DR: Results suggest that the antigen is a complex ganglioside in plasma membranes of retina neuron cell bodies but not axons or dendrites, which suggests that antibody A2B5 cytotoxicity against retina cells is inhibited by a GQ gangliosiside fraction from bovine brain but not by other purifiedgangliosides tested.
Abstract: Fusion of spleen cells from a mouse immunized with chicken embryo retina cells with clonal mouse myeloma cells yielded a lymphocyte hybrid cell line that produced antibody that bound to neural tissue such as retina, brain, spinal cord, and dorsal root ganglia but not to other tissues tested. The antigen was shown by indirect immunofluorescence to be associated with plasma membranes of most, or all, neuron cell bodies in chicken retina, but little or no antigen was detected on axons or dendrites, Muller cells, or retina pigment cells. The activity of antigen A2B5 is relatively stable at 100 degrees C, is insensitive to trypsin, exhibits the solubility properties of a ganglioside, and is destroyed by neuraminidase. Antibody A2B5 cytotoxicity against retina cells is inhibited by a GQ ganglioside fraction from bovine brain (estimated half-maximal inhibition at 0.2 microM) or by N-acetylneuraminic acid (half-maximal inhibition at 5000 microM) but not by other purified gangliosides tested. These results suggest that the antigen is a complex ganglioside in plasma membranes of retina neuron cell bodies but not axons or dendrites.
940 citations
TL;DR: A modification of the cell fusion procedure was used to recover stable hybrid cell lines secreting IgG antibodies to mouse major histocompatibility complex alloantigens and mouse immunoglobulin allotypes.
Abstract: Advances in somatic cell hybridization techniques have made it possible to generate hybrid cell lines producing monospecific antibodies directed at desired antigenic determinants (1). In this paper a modification of the cell fusion procedure (2,3) was used to recover stable hybrid cell lines secreting IgG antibodies to: (a) mouse major histocompatibility complex (MHC) alloantigens (H-2K and I-A); and (b) mouse immunoglobulin (Ig) allotypes (Ig-1b, Ig-5a, and Ig-5b).
TL;DR: It is demonstrated that, after 3 weeks, most of the Langerhans cells in parental skin which had been transplanted on to F1 hybrids were of recipient origin whereas keratinocytes remained of donor origin; this indicates that the LC are derived from a mobile pool of cells.
Abstract: Langerhans cells constitute a morphologically well characterised subpopulation (3--8%) of mammalian epidermal cells which, in contrast to the bulk of epidermal cells, bear Fc-IgG and C3 receptors, express immune response-associated (Ia) antigens and function as antigen-presenting cells and allogeneic stimulatory cells to primed T lymphocytes. The ontogeny of Langerhans cells has been a subject of considerable debate since their discovery. Although some studies suggest that Langerhans cells are of mesenchymal as opposed to neural or melanocytic origin, direct evidence for this has not been presented. In this study we demonstrate that, after 3 weeks, most of the Langerhans cells (LC) in parenteral skin which had been transplanted on to F1 hybrids were of recipient origin whereas keratinocytes remained of donor origin; this indicates that the LC are derived from a mobile pool of cells. Furthermore, in studies of skin from radiation-induced bone marrow chimaeric animals we found that, depending on the strain combination, up to 80% of the epidermal LC were derived from the bone marrow of the donor animals.
TL;DR: A rapid and very sensitive method for detecting proteins as antigens after their separation in polyacrylamide/agarose composite gels, with or without sodium dodecyl sulfate.
Abstract: We describe a rapid and very sensitive method for detecting proteins as antigens after their separation in polyacrylamide/agarose composite gels, with or without sodium dodecyl sulfate. The polyacrylamide matrix is crosslinked with a reagent that can be cleaved with periodate or alkali to facilitate transfer of the protein bands to diazobenzyloxymethyl-paper, where they are coupled covalently. Specific proteins are detected by autoradiography after sequential incubation with unfractionated, unlabeled specific antiserum and 125I-labeled protein A from Staphylococcus aureus. Antibody and protein A can be removed with urea and 2-mercaptoethanol, and the same paper can be probed again with a different antiserum. An antiserum specific for the simian virus 40 virion proteins VP3 and VP2 has been prepared; it does not crossreact with VP1, as demonstrated by this method. An antiserum raised in rabbits against simian virus 40-transformed rabbit kidney cells is shown to be directed primarily against a periodate-sensitive moiety present in tumor (T) antigen from infected or transformed cells, whereas an antiserum raised in rabbits against large T antigen purified from lytically infected monkey kidney cells by electrophoresis in the presence of sodium dodecyl sulfate [Lane, D.P. & Robbins, A.K. (1978) Virology 87, 182-193] is directed primarily against determinants that are not sensitive to periodate.
TL;DR: Chicken hematopoietic cells transformed in vitro and in vivo by seven strains of replication-defective avian leukemia viruses were assayed for the expression of six erythroid and five myeloid differentiation parameters, including differentiation-specific surface antigens as detected by newly developed antisera.
TL;DR: In this article, a protein with an apparent molecular weight of 53,000 in extracts of transformed BALB/c cells was detected in normal adult mouse fibroblasts, lymphoid cells, or hematopoietic cells or in mouse embryo cells.
Abstract: Antisera prepared against BALB/c Meth A sarcoma in syngeneic or compatible F1 mice recognize a protein with an apparent molecular weight of 53,000 in extracts of [35S]methionine-labeled transformed BALB/c cells. This component, designated p53, was not detected in normal adult mouse fibroblasts, lymphoid cells, or hematopoietic cells or in mouse embryo cells or 3T3 cells. An extensive variety of antisera, including alloantisera and heterologous antisera directed against structural antigens of murine leukemia viruses, was tested for reactivity with p53; other than Meth A antisera, only comparably prepared antisera against another BALB/c sarcoma, CMS4, had anti-p53 activity. All transformed mouse cells tested were found to express p53; these tests included chemically induced sarcomas, leukemias, spontaneously transformed fibroblasts, and cells transformed by simian virus 40 and murine sarcoma virus. The presence of p53 in tumors of no known viral etiology indicates coding by resident cellular genes; this does not exclude endogenous viruses as the source of coding sequences or the possibility that transforming viruses code directly for p53.
TL;DR: Two hybridomas and their clones secreted antibodies binding specifically to human colorectal carcinoma cells either grown in culture or obtained from patients, but did not bind to normal colonic mucosa or other normal and malignant human cells.
Abstract: Fusion of P3 X 63 Ag8 mouse myeloma cells with splenocytes obtained from mice immunized with cells derived from human colorectal carcinomas resulted in the production of antibody-secreting hybridomas. Two hybridomas (1083-17 and 1116-56) and their clones secreted antibodies binding specifically to human colorectal carcinoma cells either grown in culture or obtained from patients, but did not bind to normal colonic mucosa or other normal and malignant human cells. The binding specificity was consistent in three assays: radioimmunoassay, mixed hemadsorption, and immunofluorescence. Adsorption of these antibodies to colorectal carcinoma cell lines totally eliminated their specific binding.
TL;DR: A fraction of la‐like glycoproteins was prepared from rat thymocytes by lentil lectin affinity chromatography and gel filtration in deoxycholate, and the purified Ia glycoprotein partially inhibited the binding to thoracic duct lymphocytes of an alloantiserum which detects Ia antigens linked to the major histocompatibility complex.
Abstract: A fraction of la-like glycoproteins was prepared from rat thymocytes by lentil lectin affinity chromatography and gel filtration in deoxycholate. Spleen cells from mice immunized with this preparation were fused with myeloma cells to produce antibody-secreting hybrid cell lines. Antibody from four lines called MRC OX, 3, 4, 5, 6 reacted with the la-like glycoproteins, and MRC OX 3 antibody recognized an antigenie determinant polymorphic in the rat. All four antibodies also bound to mouse spleen cells and all detected polymorphisms. Studies on recombinant mouse strains suggest that the determinants are coded by the I-A subregion of the H-2 complex. MRC OX 3 correlates with Ia specificity 9, while MRC OX 4, 5, 6 correlate with specificity 17 or 18. MRC OX 4 monoclonal antibody was used for affinity chromatography to purify Ia glycoproteins from rat spleen. The rat Ia glycoprotein complex was composed of two noncovalently linked polypeptide chains of apparent mol. wt. (unreduced) 30 000 and 24 000 as determined by polyacrylamide gel electrophoresis in sodium dodecyl sulfate. The purified Ia glycoprotein partially inhibited the binding to thoracic duct lymphocytes of an alloantiserum which detects Ia antigens linked to the major histocompatibility complex. The monoclonal anti-la antibodies bound to the majority of peripheral B lymphocytes and 18% of thymocytes, but did not significantly bind to peripheral T lymphocytes. There were on average 150000 molecules of Ia glycoprotein per la-positive B lymphocyte, and 45 000 molecules per la-positive thymocyte.
From the same fusion, another cell line was prepared called MRC OX 2 which secretes monoclonal antibody to a previously undefined thymus glycoprotein of apparent mol. wt. 60000. Preliminary studies showed that the antigen was expressed on all thymocytes and on peripheral B lymphocytes in smaller amounts. It was also present in brain, but not liver or kidney homogenate.
TL;DR: In this article, the authors estimate the probability that an immune system with N Ab monospecific antibodies in its repertoire can recognize a random foreign antigen, and they conclude that multispecific recognition is a more reliable method of distinguishing between molecules than single site recognition.
Journal Article•
TL;DR: The results suggest that the W6/32 antigenic determinant involves only amino acids of the HLA-A,B,C chain and is a product of their three dimensional configuration.
Abstract: The isolated HLA-A chain from intact 125I-HLA-A2 antigens weakly bound to W6/32 antibody in contrast to 125I-β2-microglobulin (β2m) isolated from the same preparation of HLA-A2 antigens that showed no demonstrable binding. when an excess of cold β2m was added to the isolated 125I-HLA-A2 chain, the binding to W6/32 antibody was considerably enhanced. These results suggest that the W6/32 antigenic determinant involves only amino acids of the HLA-A,B,C chain and is a product of their three dimensional configuration. Stable maintenance of this configuration appears to be dependent on the association of the HLA-A,B,C chain with β2m.
TL;DR: This chapter discusses the nature of endotoxins and their interactions with cells of the immune system, leading to direct interaction of endotoxin with B lymphocytes leading to the formation of antibodies to endotoxin as well as a spectrum of other immunoglobulin molecules.
Abstract: Publisher Summary This chapter discusses the nature of endotoxins and their interactions with cells of the immune system. The direct interaction of endotoxin with B lymphocytes leading to the formation of antibodies to endotoxin as well as a spectrum of other immunoglobulin molecules is discussed. In addition, the interactions of endotoxins with T cells and macrophages and the associated immunoregulatory effects are discussed. The central role of the lipid A portion of the endotoxin molecule in cellular activation and the molecular events occurring at the cell surface in the course of stimulation are presented. The potential of endotoxins as therapeutic manipulators of the immune response in man is also evaluated. Major direct interactions of endotoxins with B lymphocytes have been documented, leading to synthesis and secretion of antibody directed not only against antigenic determinants on the endotoxin molecules themselves, but also with specificities characteristic of the complete repertoire of variable region gene products. Knowledge of the immunobiology of endotoxins has prompted investigations in their therapeutic uses in man as both antigenically distinct and cross-reactive immunogens in protection against gram-negative infections.
TL;DR: The nature of Ia antigens which appear on human T cells after activation and the stimuli required for their expression was examined utilizing a monoclonal antibody reactive with the Ia antigen framework.
Abstract: The nature of Ia antigens which appear on human T cells after activation and the stimuli required for their expression was examined utilizing a monoclonal antibody reactive with the Ia antigen framework. T cells were purified using monoclonal antibodies directed either at the entire T-cell population (OKT3) or the T-cell inducer subset (OKT4). By indirect immunofluorescence, it was shown that the human T-cell population contains no detectable Ia+ cells in the resting state. In contrast, in excess of 60% of the T-cell population expresses Ia antigen after alloactivation in the mixed lymphocyte culture. Moreover, these Ia antigens are expressed within both the OKT4+ and OKT4- subsets. Similarly, phytohemagglutinin and concanavalin A induced approximately 20% of peripheral T cells to express Ia antigen and the expression of these antigens is not restricted to either OKT4 subset. In contrast, only the inducer T-cell population which proliferates maximally to soluble antigen expresses Ia antigens after activation by tetanus toxoid. Thus, the expression of human Ia antigens on unique T-cell subsets depends upon the activation stimuli utilized and ability of the individual subset to respond to a given stimulus. Additional studies indicated that Ia antigens appear on previously Ia- T cells after activation and do not result from clonal expansion of a small subset of Ia+ T cells.
TL;DR: A composite DNA sequence of regions of hepatitis B virus, determined from a series of recombinant plasmids, reveals the genes for the surface antigen and the core antigen of the virus.
Abstract: A composite DNA sequence of regions of hepatitis B virus, determined from a series of recombinant plasmids, reveals the genes for the surface antigen and the core antigen of the virus. The sequence of the core antigen shows it to be a DNA binding protein. The core antigen gene is expressed in Escherichia coli and when injected into rabbits the bacterial product induces antibodies which react with core antigen isolated from human sources.
Journal Article•
TL;DR: Treatment of peripheral lymphocyte populations with monoclonal antibody plus C eliminated effector cytotoxic T lymphocytes, their precursors, and the mitogenic response to Con A, but did not affect the response to LPS.
Abstract: Fusion of cells of the mouse myeloma line, P3/X63-Ag8 with spleen cells from AKR/J mice immunized against C3H thymocytes or from (BALB/c × BALB.K)F 1 mice immunized against AKR/J thymocytes gave rise to hybrid cell lines that continuously secrete antibodies specific for the Thy-1.2 and Thy-1.1 antigens, respectively. Monoclonal antibodies from four such cell lines were analyzed in detail. All were 19S IgM, and, in the presence of complement (C), had high lytic titers on T cells of the appropriate antigenicity. Their specificity was shown by lysis of thymocytes from Thy-1 congenic mouse strains, A/J(Thy-1.2) and A.Thy 1.1. Furthermore, they lyse only 60 to 70% of lymph node cells, suggesting cytotoxicity for mature T cells and not B cells. Treatment of peripheral lymphocyte populations with monoclonal antibody plus C eliminated effector cytotoxic T lymphocytes, their precursors, and the mitogenic response to Con A, but did not affect the response to LPS. Purified, fluorescein-labeled monoclonal anti-Thy-1 antibody could be used to distinguish T and B cells. Purified antibody coupled to Sepharose 6MB was used to separate viable T and B cells. Two independently isolated anti-Thy-1.2 hybridomas are indistinguishable and bind the same determinant whereas a third is unique and may bind a separate site.
TL;DR: Murine helper T cells activated to sheep or horse erythrocyte antigens in vivo have been established as continuous cell lines in culture and stable helper activity for greater than 50 wk in culture is shown.
Abstract: Murine helper T cells activated to sheep or horse erythrocyte antigens in vivo have been established as continuous cell lines in culture. T cells require the presence of a T-cell growth factor (TCGF) for continuous proliferation. TCGF purified from murine, rat, or human sources all stimulate murine T-cell growth. The T-cell mitogens concanavalin A and phytohemagglutinin do not stimulate cell proliferation in continuous T-cell lines. All cells that grow in the presence of TCGF express Thy-1 antigens. Helper activity of T-cell lines is both antigen specific and effective for syngeneic or F1 B cells. Supernates from T-cell lines do not contain antigen-specific or nonspecific helper factors. Although several T-cell lines have shown stable helper activity for greater than 50 wk in culture, other cell lines have shown a gradual decline in effector function. The procedure used to establish and maintain proliferation of T cells in culture should be suitable for the selection and growth of antigen-specific effector T cells from each subclass.
TL;DR: Polyoma T antigen immunoprecipitates contain a protein kinase-like activity which preferentially phosphorylates material of 50-60,000 daltons molecular weight, which behaves identically to phosphate and differently than phosphorylated serine, threonine, lysine and histidine.
TL;DR: Spleen cells from a BALB/c mouse that had been immunized with human thymocytes were fused with the myeloma line P3‐NS1/1Ag 4.1 and one of the resulting hybrid clones secreted an antibody that was highly specific for humanThymocytes, designated HTA1.
Abstract: Spleen cells from a BALB/c mouse that had been immunized with human thymocytes were fused with the myeloma line P3-NS 1/1 Ag 4.1. One of the resulting hybrid clones (NA 1/34) secreted an antibody that was highly specific for human thymocytes. Eighty-five % of thymocytes expressed the antigen designated HTA1. There were an estimated 15 x 10(4) molecules of HTA 1 per cell, and it is therefore a major surface molecule. The expression of this antigen on thymocytes appears to be reciprocal to HLA, as recognized by another monoclonal antibody W6/32. Immunoprecipitated material from [125I]-labeled thymocyte membranes was analyzed by polyacrylamide gel electrophoresis in sodium dodecyl sulfate which disclosed a single component of 45,000 molecular weight.
TL;DR: This chapter describes the interaction of immune complexes (ICs) with complement and with the cells of the immune system, thereby making it possible to identify the antigens involved in immune processes of a great many diseases, including those of unknown etiology.
Abstract: Publisher Summary This chapter describes the interaction of immune complexes (ICs) with complement and with the cells of the immune system. The effect of immune complexes depends to a great extent on their antigen–antibody ratio so that their influence, either stimulatory or suppressive, is itself modulated by quantitative aspects of the immune response. The development of numerous techniques for the detection and quantitation of immune complexes has stimulated clinically related research and expanded the list of diseases in which immune complexes appear to play an important role. An extension of this diagnostic technology is the ability to isolate immune complexes and, in turn, their antigenic component, thereby making it possible to identify the antigens involved in immune processes of a great many diseases, including those of unknown etiology. In vivo and in vitro experiments have clarified many factors involved in IC formation, removal, and localization as well as the mechanisms of IC-induced inflammatory reactions. An individual can make an immune response to a large number of exogenous and a smaller number of endogenous antigens. Depending upon the availability of antigen, the antibodies so produced form ICs, which for the most part serve the purpose of aiding the host in eliminating potential pathogens.
TL;DR: It was evident that the T blasts expressed similar HLA-DR determinants to those on B cells from the same donor; occasional minor differences between stimulated T cells and autologous B-cell lines or fresh B cells were encountered.
Abstract: Human T-cell blasts were generated by stimulation with mitogens and antigens. A proportion of these blasts expressed Ia antigens detectable by immunofluorescence with both allo- and hetero-antiserums. The maximal expression of Ia antigens was delayed and usually occurred after the peak of blastogenesis. Among the three mitogens used, pokeweed mitogen (PWM) was most effective in giving a high percentage and intense Ia staining of T-cell blasts. Phytohemagglutinin and concanavalin A blasts gave weaker and lower percentages of Ia staining. Activation by alloantigens and soluble antigens such as tetanus toxoid and purified protein derivative resulted in Ia expression on T cells comparable to PWM stimulation. Depletion of Ia+ cells from freshly isolated T cells with anti-Ia and complement decreased subsequent Ia expression, suggesting that a proportion of Ia+ blasts were derived from Ia-bearing peripheral blood T cells. When the specificities of the Ia antigens on T-cell blasts were examined with alloantiserums, it was evident that the T blasts expressed similar HLA-DR determinants to those on B cells from the same donor; occasional minor differences between stimulated T cells and autologous B-cell lines or fresh B cells were encountered.
TL;DR: The data are compatible with the assumption that the 55K proteins are largely or totally cell coded, and are not structurally related to large-T antigens, as judged by the Chromobead elution patterns of their methionine-labeled tryptic peptides.
Abstract: In addition to the virus-coded large-T and small-t antigens, two new classes of proteins were immunoprecipitated by anti-simian virus 40 (SV40) tumor serum from extracts of various SV40-transformed cell lines. These were as follows: (i) proteins (termed "super-T proteins") with an Mr higher than that of large-T antigen (86,000), which were found in many SV40-transformed cell lines derived from mouse and rat cells (super-T proteins and large-T antigen appeared to have closely related structures as judged by the Chromobead elution patterns of their methionine-labeled tryptic peptides); (ii) proteins (termed "55K proteins") with an Mr ranging from 50,000 to 60,000, which were present in all SV40-transformed cell lines examined so far, including those obtained by chromosome-mediated gene transfer. The 55K proteins were not structurally related to large-T antigens, as judged by the Chromobead elution patterns of their methionine-labeled tryptic peptides. Our data are compatible with the assumption that the 55K proteins are largely or totally cell coded.