bluuebunny/crossref_metadata_2025_split huggingface dataset:
The role of sialic acid in the functional activity and the hepatic clearance of C1-INH.
Authors: Minta J O 
Published: December 2022

Abstract
The immunochemical properties, catabolic clearance, and organ distribution of highly purified radiolabeled human C1-INH were studied after treatment with glycosidases. The antigenicity and C1s inhibitory activity of C1-INH were unimpaired after removal of sialic acid residues (60%) or sialic acid and galactose residues (60 and 20%, respectively) with immobilized neuraminidase and beta-galactosidase. Treatment of C1-INH with neuraminidase was associated with increased cathodal migration of the glycoprotein. In vivo studies in the rabbit, however, showed that removal of sialic acid residues resulted in rapid blood clearance of C1-INH and enhanced localization of the asialo C1-INH in the liver. Subsequent removal of penultimate galactose residues returned the survival time in the circulation and organ distribution to near normal. Additionally, simultaneous infusion of asialo-C1-INH with asialo alpha 1-acid glycoprotein, a protein known to bind to hepatic asialoglycoprotein receptors, dramatically extended the intravascular survival time of asialo C1-INH. In agreement with the observations on other plasma glycoproteins, these results indicate that desialylation of C1-INH results in rapid clearance by hepatic asialoglycoprotein receptors.
Monoclonal antibodies to mouse MHC antigens. III. Hybridoma antibodies reacting to antigens of the H-2b haplotype reveal genetic control of isotype expression.
Authors: Ozato K , Sachs D H 
Published: December 2022

Abstract
Eleven hybridoma antibodies directed against mouse major histocompatibility complex products of the H-2b haplotype have been produced and characterized. Of 7 antibodies reacting to H-2Kb and/or H-2Db antigens, all cross-reacted with other H-2 antigens, and 5 exhibited no correspondence with a known H-2 specificity established in the H-2 chart. Four anti-Iab antibodies all reacted with antigens encoded by the I-A subregion. Some of these antibodies showed no cross-reaction with other haplotypes, indicating reactions to private specificities of the I-Ab antigen. In addition, these anti-Ia antibodies appeared to be capable of distinguishing fine determinant differences, which corresponding alloantisera failed to reveal. A high frequency of hybridomas secreting IgM antibodies was found after fusions of spleen cells obtained from C3H anti-C3H.SW immunized mice, in contrast to the dominance of IgG hybridomas produced previously by fusions of spleen cells from mice immunized in the reverse direction. An isotype analysis of conventional cytotoxic alloantisera from the same strain combinations was therefore performed. The same correlation with respect to isotype expression was found, indicating that hybridoma antibodies reflect normal antibody responses and suggesting H-2-linked control of this expression.
Antigen-specific clones of proliferating T lymphocytes. I. Methodology, specificity, and MHC restriction.
Authors: Sredni B , Tse H Y , Chen C , Schwartz R H 
Published: December 2022

Abstract
In this report we describe in detail a new method for cloning antigen-specific, proliferating T lymphocytes directly from primed murine lymph nodes after 3 days of activation in vitro. After expansion in liquid culture the cells from the colonies were shown to be antigen specific and to require I-A histocompatible, irradiated spleen cells for stimulation. For hapten-carrier-type antigens, the T cells were shown to be carrier specific in their recognition but they were also capable of distinguishing the presence of the hapten. Recloning of small numbers of these cells in soft agar under conditions of high plating efficiency yielded true clones (i.e., populations derived from a single cell) whose antigen specificity was identical to that of cells from the original colony. The fact that a clone of T cells was I-A restricted in its antigen recognition demonstrates that suppressor T cell function cannot account for the phenomenon of major histocompatibility complex restriction.
Cross-reaction of a rat-anti-mouse phagocyte-specific monoclonal antibody (anti-Mac-1) with human monocytes and natural killer cells.
Authors: Ault K A , Springer T A 
Published: December 2022

Abstract
A monoclonal antibody produced by a hybridoma cell line that has previously been shown to recognize an antigen present on murine macrophages and granulocytes (Mac-1) has now been shown to bind to human monocytes and polymorphonuclear leukocytes. Human monocytes bind about 40,000 M1/70 (anti-Mac-1) F(ab')2 or IgG molecules per cell in saturating conditions. In addition, M1/70 antibody recognizes a small population (less than 10%) of human blood lymphocytes. These cells express approximately 3-fold fewer Mac-1 antigen determinants than monocytes. Separation of this lymphocyte subset on a fluorescence-activated cell sorter has shown that all the natural killing activity in human blood can be found among these cells. Similarly, separation of the natural killer cells by an independent method based on their surface Fc receptor has shown that nearly all of them can be labeled by the hybridoma antibody. The same results are obtained when an F(ab')2 fragment of the M1/70 hybridoma antibody is used. The anti-Mac-1 antibody does not interfere with binding to the Fc receptor, nor does it interfere with either natural killing or antibody-dependent cellular cytotoxicity mediated by these cells. We conclude that there is a similar antigenic structure on the surface of murine and human monocytes and granulocytes and that this structure is also found on human natural killer cells.
Human melanoma-associated antigens: role of carbohydrate in shedding and cell surface expression.
Authors: Morgan A C , Galloway D R , Imai K , Reisfeld R A 
Published: December 2022

Abstract
The shedding of 2 tumor-specific glycoprotein antigens from human melanoma cells into spent culture medium was selectively inhibited by nontoxic doses (0.5 microgram/ml) of tunicamycin, an inhibitor of N-asparagine-linked glycosylation. The inhibition of shedding of these 2 antigens with m.w. of 240K and 94K is complete within 24 hr after addition of tunicamycin. During this time interval, our data suggest that these glycosylated cell surface antigens are replaced by their nonglycosylated forms. Removal of tunicamycin or addition of N-acetyl glucosamine restores shedding of these melanoma-associated antigens with initially reduced glycosylation. This same selective inhibition of shedding was observed with cultures adapted to grow in high doses (2.5 microgram/ml) of tunicamycin that otherwise killed &gt; 98% of the cells upon first exposure. In contrast to other glycoproteins found in spent culture medium of melanoma cells, the shedding of melanoma-associated antigens is strictly dependent on glycosylation.
Demonstration of IgG-Fc and C3 receptors on adult Schistosoma mansoni.
Authors: Tarleton R L , Kemp W M 
Published: December 2022

Abstract
Previous studies have indicated that adult schistosomes have an affinity for both IgG and C; however, thorough investigations on the possible presence of receptors for these serum proteins on the adult schistosome tegument have not been attempted. The present study presents evidence for both IgG-Fc and C3 receptors on adult schistosomes. An indirect assay utilizing fluoresceinated Staphylococcus aureus was developed to detect antigen-antibody (Ag-Ab) and antigen-antibody-C (Ag-Ab-C) binding to adult parasites. Detection of Ag-Ab and Ag-Ab-C complex binding was dependent on the presence of a metabolic inhibitor in the incubation mixture presumably to prevent shedding of bound complexes. Ag-Ab complex binding required the presence of an intact Fc on the IgG of the complex and could be partially inhibited by preincubation of parasites in heat-aggregated IgG or an isolated Fc preparation. Binding of Ag-Ab-C complexes was dependent on active C3 in the C source but not on an intact Fc on the IgG of the complex. Ag-Ab-C binding could be blocked by prior incubation of parasites in heat-aggregated IgG-C but not by C alone. Binding of host serum proteins to IgG-Fc and C3 receptors on adult schistosomes may aid parasite survival by helping to prevent immune detection.
Newborn T cell suppression: early appearance, maintenance in culture, and lack of growth factor suppression.
Authors: Hayward A R , Kurnick J 
Published: December 2022

Abstract
Human newborn T lymphocytes suppress the responses of adult lymphocytes to several stimuli, including the T dependent differentiation of adult B cells to plasma cells (PC) by pokeweed mitogen (PWM) stimulation. We tested blood from premature babies to show that the suppressor activity for PWM-induced B cell differentiation appeared by 26 weeks' gestation. Cord blood from full term babies delivered by Caesarean section also suppressed PC differentiation showing that maternal labor is not a prerequisite for suppression. Eleven percent of freshly isolated newborn T cells bore the putative suppressor phenotype OKT 8 and 81% had the putative helper phenotype OKT 4, so the increased suppression and diminished help of newborn T cells was not associated with an imbalance of phenotypic helper or suppressor cells. The function of newborn T cells was further investigated by establishing the cells in continuous culture with T cell growth factors. The polyclonal lines obtained suppressed adult PWM-induced PC differentiation and were inefficient helpers so their functional characteristics appear to be maintained in culture without changes in the balance of help and suppression. PHA-stimulated newborn lymphocytes were themselves efficient producers of T cell growth factors. We conclude that newborn T cells can suppress without lectin activation and that the suppressor activity that is found is a stable intrinsic characteristic of the cell.
Tumor-associated antigens in spent medium of human melanoma cells: immunochemical characterization with xenoantisera.
Authors: Galloway D R , McCabe R P , Pellegrino M A , Ferrone S , Reisfeld R A 
Published: December 2022

Abstract
Xenoantisera to human melanoma cells and to partially purified melanoma-associated antigens were coupled to protein A-bearing Staphylococcus Aureus or protein A-Sepharose and used as immunoadsorbents for the indirect immunoprecipitation of intrinsically radiolabeled proteins released into culture medium from various cultured human tumor and nontumor cell lines. These radiolabeled immunoprecipitates when analyzed by SDS-PAGE revealed highly reproducible molecular profiles of proteins and glycoproteins released by various cultured tumor lines and control cells into their spent culture media. A comparison of molecular profiles together with data indicating the binding specificity of known xenoantisera produced against human melanoma cells or their extracts led to the discovery of 2 macromolecules that are associated with human melanoma cells; a glycoprotein with a subunit m.w. of 240,000 (240K) and a single-chain glycoprotein of 94,000 (94K) m.w. also found in association with human carcinoma cells are described in this report.
Properties of a minor cross-reactive idiotype associated with anti-p-azophenylarsonate antibodies of A/J mice.
Authors: Gill-Pazaris L A , Lamoyi E , Brown A R , Nisonoff A 
Published: December 2022

Abstract
Experiments are described that further characterize an A/J anti-phenylarsonate (anti-Ar) antibody population, which is idiotypically cross-reactive within the strain but differs from the family of antibodies expressing the major cross-reactive idiotype (CRI). This population has been designated as expressing a "minor" cross-reactive idiotype. Chain recombination studies with hybridoma products (HP) revealed that 2 of 3 HP expressing minor idiotypic determinants contain L chains that are idiotypically closely related to L chains in anti-Ar antibodies bearing the major CRI. The results indicate the expression of the same or very similar L chains in antibodies that differ in idiotype. The minor idiotypic population in serum was investigated by separating antibodies with minor and major idiotypic determinants by use of an immunoadsorbent containing anti-idiotype directed to an HP expressing the major CRI. Studies with the nonadherent, minor idiotypic population showed that such molecules constitute about 8 to 10% of the anti-Ar antibodies in a pool of serum but that individual sera vary markedly in their content of anti-Ar antibodies bearing minor idiotypes. Preinoculation of mice with conventional anti-idiotypic antiserum before immunization with KLH-Ar was found to suppress the appearance of the minor idiotypes as well as the major CRI upon subsequent immunization. The suppression of the minor idiotypic population is presumably mediated by the small fraction of rabbit anti-id antibodies directed against such molecules.
Immunogenicity of haptenated schistosomula in vitro.
Authors: Abbas A K , James S L , Sher A 
Published: December 2022

Abstract
Skin-stage schistosomula of Schistosoma mansoni modified with 2,4,6-trinitrophenyl (TNP) induce primary anti-TNP plaque-forming cell (PFC) responses in normal mouse spleen cells in vitro. The PFC are TNP-specific, and the response is dependent on adherent cells and T lymphocytes. In contrast, comparably haptenated lung stage larvae are weakly or nonimmunogenic in this system, and their inability to stimulate anti-TNP PFC cannot be attributed to a toxic or suppressive effect. These observations suggest that maturation of schistosomula in vivo is accompanied by a decline in their immunogenicity, which, along with other adaptive mechanisms, may promote the survival of parasites in the host environment.
A mechanism of migration inhibition in delayed-type hypersensitivity reactions. II. Lymphokines promote procoagulant activity of macrophages in vitro.
Authors: Geczy C L , Hopper K E 
Published: December 2022

Abstract
Although lymphokine supernatants had no procoagulant activity per se, guinea pig peritoneal exudate cells (PEC), incubated with lymphokine supernatants or with a lymphokine fraction of 35,000 to 50,000 daltons decreased the recalcification time of platelet-poor plasma. PEC from animals immunized with BCG or with ovalbumin and incubated with the corresponding antigen had increased procoagulant activity. Similar effects were observed with PEC incubated with endotoxin. The induction of procoagulant activity by the cells was accompanied by a concomitant decrease in their ability to respond to chemotactic agents and to migrate from capillary tubes. Separation of exudate cells by sedimentation velocity indicated that large macrophages had the highest degree of procoagulant activity after incubation with lymphokines. The clotting time of Factor IX-deficient plasma was decreased by lymphokine-treated macrophages, indicating that the extrinsic clotting sequence may be activated as a result of increased tissue factor on the treated cells. Heparin abolished the ability of lymphokines to inhibit macrophage migration.
Immune and enzyme histochemical studies of a human hepatocellular carcinoma cell line producing hepatitis B surface antigen.
Authors: Gerber M A , Garfinkel E , Hirschman S Z , Thung S N , Panagiotatos T 
Published: December 2022

Abstract
PLC/PRF/5, a tissue culture cell line derived from a human hepatocellular carcinoma and producing hepatitis B surface antigen (HBsAg), was studied by immune and enzyme histochemical techniques. HBsAg was demonstrated in the cytoplasm and on the surface of tumor cells. The percentage of HBsAg-positive cells in subculture increased with time until almost all cells expressed HBsAg when the monolayer reached confluence. Similar patterns were found for alpha 1-anti-trypsin and carcino-embryonic antigen, whereas alpha-fetoprotein was observed only in small foci of cells. Hepatitis B core antigen and albumin were not detected. gamma-Glutamyl transferase activity was markedly increased in the tumor cells, whereas adenosine triphosphatase and glucose-6-phosphatase activities were not demonstrable. Patterns of antigenic expression and enzyme phenotype of PLC/PRF/5 cells show remarkable resemblance to those observed in vivo in human hepatocellular carcinoma. Therefore, this cell line may be a useful model to study the control and modulation of both oncofetal antigens and HBsAg.
A comparison of the suppressor cells found in the spleens of 89SR-treated mice and in normal murine bone marrow.
Authors: Levy E M , Corvese J S , Bennett M 
Published: December 2022

Abstract
Normal murine bone marrow cells and spleen cells of mice treated with 89Sr both have suppressive activity. These nonspecific suppressor cells inhibit the ability of normal spleen cells to undergo antibody responses in vitro. After being precultured for 24 hr, these cells will also suppress antibody responses in vivo and the responses of normal spleen cells to T and B cell mitogens in vitro. These cells have previously been shown not to be mature T or B lymphocytes or macrophages. Velocity sedimentation and cell-size analysis indicated that both suppressor cells are large (approximately 206 mu3). Mitomycin C treatment eliminated the ability of both suppressor cells to inhibit an in vitro antibody response. In contrast, this treatment did not reduce the ability of the cells to suppress a mitogenic response. Irradiation (1000 R) was also ineffective in eliminating the ability of either cell to suppress a mitogenic response We conclude that the 2 suppressor cells are closely related if not identical, and we speculate that these cells may function in vivo to suppress immune reactivity in areas of intense hematopoiesis.
Membrane protein synthesis in mitogen-stimulated human T lymphocytes.
Authors: Udey M C , Parker C W 
Published: December 2022

Abstract
Proteins were biosynthetically labeled with [35S]-methionine in resting and mitogen-stimulated human peripheral blood lymphocytes. Lymphocytes were disrupted by sonication, the membrane fraction was isolated by differential centrifugation, and radiolabeled membrane proteins were identified after 2-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and autoradiography. The T cell mitogen concanavalin A (Con A) produced selective increases in the incorporation of [35S]-methionine into a membrane protein (or family of 4 structurally related membrane proteins) with an apparent m.w. of 28,000 and approximate isoelectric points (pI) of 5.5, 5.7, 6.0, and 6.2 (p28). Quantitative microdensitometry was used to evaluate p28 synthesis in a large number of different lymphocyte donors. Consistent and highly significant differences between resting and stimulated cells were demonstrable whether the 4 p28 spots were considered individually (p less than 0.0025) or in sum (p less than 0.0005). The p28 response to Con A was shown to be contained within the T lymphocyte fraction of mononuclear cells, was dose dependent over the mitogenic concentration range for Con A, and was blocked by alpha-methyl-D-mannoside, a sugar inhibitor of Con A binding. Differences between stimulated and resting cells were readily apparent within 2 hr of activation and became progressively larger with time. Protein p28 was prominently represented in plasma membranes isolated on discontinuous sucrose density gradients and was identified as a cell surface glycoprotein based on studies in which intact stimulated cells were exposed to degradative enzymes. This protein was lost from cells treated with pronase, whereas neuraminidase digestion changed the pI of p28 from a range of 5.5 to 6.2 to a range of 6.1 to 6.4 without changing the apparent m.w.
Human T cell colony formation in microculture: analysis of growth requirements and functional activities.
Authors: Gelfand E W , Lee J W , Dosch H M , Price G B 
Published: December 2022

Abstract
A microculture method in methylcellulose has been developed for the study of human T cell colony formation. The technique is simple, reliable, does not require preincubation with lectin and requires small numbers of cells. Colony formation was dependent on the presence of phytohemagglutin-conditioned medium, a T colony precursor cell (TCPC), and a "helper" or accessory T cell. Plating efficiency was increased 10-fold in the presence of irradiated feeder cells. Progenitors of the T colony cells were identified in peripheral blood, tonsil, and spleen but not in thymus or thoracic duct. They were isolated in the E-rosetting, theophylline-resistant, Fc-IgG-negative cell populations. In peripheral blood the frequency of TCPC and accessory cells, the T colony forming unit, was estimated to be 8 X 10(-3). Colony cells proliferated in response to lectins and allogeneic cells. Forty to 80% of the cells were Ia-positive and stimulated both autologous and allogeneic mixed lymphocyte responses. They were incapable of mediating antibody-dependent cytotoxicity. In contrast, they were effective in assays of spontaneous cytotoxicity but only against certain target cells. This method for the analysis of T colony formation should prove valuable in the functional analysis of T cell subsets in immunodeficiency states or the transplant recipient.
Suppression of the mixed leukocyte response and of graft-vs-host disease by spleen cells following total lymphoid irradiation (TLI).
Authors: King D P , Srober S , Kaplan H S 
Published: December 2022

Abstract
Total lymphoid irradiation (TLI) was administered to mice as 17 fractions of 200 rads delivered to the major lymphoid organs. Spleen cells capable of suppressing the in vitro mixed leukocyte response (MLR) and in vivo graft-vs-host disease (GVHD) were found in mice after treatment with TLI. Suppression was not antigen specific and was markedly reduced by treatment of the spleen cells with anti-Thy-1.2 antiserum and complement. Suppressor activity declined with time after irradiation and disappeared within 30 to 40 days. The evidence suggests that the suppressor cells may prevent initial BM rejection and acute GVHD in allogeneic BM transplant recipients prepared with TLI.
Identification of types of cells in human peripheral blood that bind C1q.
Authors: Tenner A J , Cooper N R 
Published: December 2022

Abstract
Earlier studies showed that approximately 26% of the cells present in human mononuclear cell preparations had the ability to bind purified monomeric C1q. The present studies were initiated to identify the cell types comprising the C1q binding population. Double marker fluorescence, rosetting, and morphologic studies on cell preparations depleted of or enriched in various cell types were simultaneously employed to identify those subpopulations that bound C1q. C1q binding was detected by fluorescent techniques (with FI-F(ab')2 anti-C1q). Monocytes in mononuclear cell preparations were detected by the ability to phagocytose carbonyl iron. B cells were identified by reactivity with rhodamine-conjugated F(ab')2 anti-human F(ab')2 and by rosetting with erythrocytes bearing C3b. These studies showed that monocytes and B lymphocytes comprised the majority of C1q-binding cells in mononuclear cell preparations, whereas T lymphocytes lacked this property. In addition, a minor population of nonphagocytic cells in such preparations that lacked B and T cell markers also bound C1q. Finally, a high but variable proportion of polymorphonuclear leukocytes bound C1q. Binding of C1q to PMN was concentration-dependent, saturable and specific and exhibited an equilibrium constant of 0.76 X 10(7) M-1. Thus, PMN also possess a specific receptor for C1q.