bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrolysis of a Synthetic Amide Substrate by Human C1 Esterase (C1s̄)
Authors: Morgan Paul H. , Nair Indira G. 
Published: December 2022

Abstract
C1 esterase (C1s̄), the enzymatically active form of the C1s subunit of the first component of complement, activates the classical complement pathway by limited proteolysis of complement components C2 and C4. In searching for chromogenic amide substrates which would reflect the physiologic function of C1s̄, it was found that preparations of C1s̄ slowly hydrolyzed N-benzoyl-L-phenylalanyl-L-valyl-L-arginine p-nitroanilide (BzPheValArgNA). Chromatographic, electrophoretic, and inhibition studies confirmed that the BzPheValArgNA-hydrolyzing activity of these preparations was attributable to C1s̄. Although C1s̄ is known to cleave a number of N-acylated α-amino acid esters, no synthetic amide substrate has been reported previously for this enzyme.
Kinetic analysis of the hydrolysis of BzPheValArgNA by C1s̄ yielded an apparent Km of 0.36 mM and a Kcat of 5.7 min-1. Enzymatic activity toward BzPheValArgNA appeared to be controlled by two ionizable groups with pKs of approximately 6.5 and 8.9. In view of the sequence homology between C1 esterase and the pancreatic serine proteases, it is suggested that these groups correspond respectively to the β-carboxyl group of aspartic acid 102 and the α-amino group of isoleucine 16 in α-chymotrypsin.
Although C1s̄ hydrolyzed BzPheValArgNA, it did not cleave N-benzoyl-DL-arginine p-nitroanilide. This finding suggests that substrate binding at the subsites occupied by the valyl and/or phenylalanyl residues is critical to the amidase activity of C1s̄.
Precipitation of Radiolabeled Antigen-Antibody Complexes with Protein A-Containing Staphylococcus Aureus
Authors: Brunda Michael J. , Minden Percy , Sharpton Thomas R. , McClatchy J. Kenneth , Farr Richard S. 
Published: December 2022

Abstract
The feasibility of using protein A-containing Staphylococcus aureus to measure antibodies in sera from several mammalian species was studied. A variety of unrelated radiolabeled antigens were tested, including components of bovine serum, DNA, and bacterial and tumor-associated extracts. The use of S. aureus was found to be a reliable way to detect and measure the primary interactions between many of the antigens and antibodies tested. Results were equivalent under many circumstances to those obtained with the ammonium sulfate and heterologous anti-immunoglobulin methods. However, some of the limitations noted were that certain antigens bound directly to S. aureus and that all classes of human immunoglobulins tested, in particular IgG3 and IgA1, were not precipitated by S. aureus. If these limitations are taken into consideration, the use of S. aureus can be of value in studying immunochemical reactions with other antigens.
In Vivo Immune Response Suppression by the Supernatant from Concanavalin A-Activated Spleen Cells
Authors: Reinertsen James L. , Steinberg Alfred D. 
Published: December 2022

Abstract
Supernatants from concanavalin A- (Con A) activated murine spleen cells have been shown to suppress the in vitro plaque-forming cell (PFC) response to sheep red blood cells (SRBC). The present study examined the effect of such Con A-activated spleen cell supernatants (herein termed CONS) on the in vivo immune response to SRBC in C57BL/6, BALB/c and CDF1 mice. CONS derived from BALB/c spleen cells suppressed direct PFC 4 and 8 days after immunization with 2 × 108 SRBC. CONS also suppressed indirect PFC 8 days after immunization, as well as serum hemagglutinins to SRBC. The PFC response of C57BL/6 (H-2b) mice was suppressed as much as that of BALB/c (H-2d) by CONS derived from BALB/c mice, indicating a lack of H-2 specificity of the CONS.
In addition to suppression of the antibody response to SRBC, in vivo CONS administration resulted in reduction in spleen cell number. This reduction was not sufficient to explain the decreased PFC response.
When the CONS was separated into &lt;10,000 m.w. and ≥ 10,000 m.w. fractions, the immunosuppressive activity was found in the &lt;10,000 m.w. fraction. This observation suggests that intact interferon, SIRS, and MIF were not responsible for the results obtained.
Nature of the Antigenic Complex Recognized by T Lymphocytes
Authors: Thomas David W. , Yamashita Uki , Shevach Ethan M. 
Published: December 2022

Abstract
We have previously demonstrated that nonimmune guinea pig T lymphocytes could be specifically sensitized with TNP-modified allogeneic macrophages after eliminating the alloreactive T cells with bromodeoxyuridine (BUdR) and light treatment. This procedure allowed the unique opportunity to use anti-Ia sera directed against the Ia antigens of only the stimulator macrophages or responder T cells to determine against which cell type anti-Ia would block TNP-specific stimulation. It was found that the TNP-specific DNA synthetic response of BUdR and light-treated T cells stimulated with TNP-modified allogeneic macrophages was totally eliminated by anti-Ia sera directed solely against the allogeneic stimulator macrophage. In contrast, anti-Ia sera directed only against the responder T cells had no effect on their response to TNP-modified allogeneic macrophages. These findings indicate that macrophage Ia antigens are required for efficient T cell-macrophage interactions and raise the possibility that T cell Ia antigens may not be required for collaboration with macrophages. This latter possibility was substantiated by experiments in which we show that treating T cells with anti-Ia sera and complement to remove the Ia-positive cells either before or after priming, or both, had no effect on their ability to be primed and restimulated with TNP-modified macrophages.
Delineation of Three Classes of CEA Antigenic Determinants: Identification of Membrane-Associated CEA as an Independent Species of CEA
Authors: Leung Julia P. , Plow Edward F. , Eshdat Yoval , Marchesi Vincent T. , Edgington Thomas S. 
Published: December 2022

Abstract
The immunochemical relationship between membrane-associated CEA (CEA-M) and isolated conventional whole CEA and the species CEA-S was investigated. These glycoproteins gave precipitin reactions of apparent identity by using antisera to CEA-M and CEA-S; however, the binding of each of these glycoproteins relative to one another by anti-tumor glycoprotein, anti-CEA-S, and anti-CEA-M anti-sera differed to a significant degree, indicative of some degree of nonidentity. Competitive inhibition radioimmunoassay with a 125I CEA-S ligand and a broadly reactive anti-CEA-S antiserum demonstrated that all three glycoproteins possessed in common antigenic determinants of the CEA group of glycoproteins but at apparent different concentration. These appeared to reflect the presence of CEA group-specific determinants. On the other hand, when 125I CEA-M and an anti-CEA-M antiserum were used in competitive inhibition assays, both CEA and CEA-S were antigenically deficient relative to CEA-M. After absorption of the anti-CEA-M with CEA, CEA-M produced complete inhibition, SDS-unfolded CEA produced 60% inhibition and CEA was unreactive. This antiserum was further absorbed with SDS-unfolded CEA and used in assay with 125I CEA-M. Although CEA-M remained reactive, CEA or CEA subjected to denaturants such as SDS, 2-mercaptoethanol, and SDS with 2-mercaptoethanol did not inhibit this assay system, indicating the absence of the remaining determinants present on CEA-M. Based on these observations we have proposed the existence not only of CEA group-specific determinants but also the existence of CEA cryptic determinants that may be generated from soluble forms of CEA and CEA-S by unfolding and exposure of cryptic sites. In addition, the existence of CEA species-specific determinants, which appear to be unique to a particular species of CEA, have been demonstrated. In a CEA-M-specific radioimmunoassay system with CEA-M absorbed antiserum the CEA-M species-specific determinants can be directly demonstrated in micro-some-rich homogenates of colonic adenocarcinomas. Thus, molecules bearing CEA-M species-specific determinants are produced by cells and are not an artifact of isolation of CEA-M. Demonstration of this third class of determinants on CEA-M in this study establishes that it is an independent species of CEA.
Migration Inhibition by an Agarose Microdroplet Assay: Monitoring of Tumor-Associated Antigens on a Simian Virus 40-Induced Sarcoma
Authors: McCoy J. L. , Padarathsingh M. , Dean J. H. , Henriksen O. , Natori T. , Law L. W. 
Published: December 2022

Abstract
Macrophage migration inhibition assays, with a direct agarose microdroplet method, were used to monitor TAA activity of preparations of SV-40-induced mKSA cells. These preparations included cell-free crude membranes, papainsolubilized and NP40 detergent-solubilized membrane extracts from mKSA tumor cells. The assay was extremely sensitive and could detect migration inhibition reactivity with all three types of antigenic preparations with concentrations as low at 250 pg protein/ml. The reactivities were quite reproducible from experiment to experiment using the same or different lots of these antigen preparations, and the reactivities were specific in that peritoneal exudate cells from BALB/c mice, immunized with antigenically unrelated but syngeneic plasmacytomas, were not inhibited by these antigens. The results demonstrated the usefulness of this assay in rapidly detecting small concentrations of partially purified TAA preparations by using small number of immune cells.
Association of a Low Molecular Weight Helper Factor(s) with Thymocyte Proliferative Activity
Authors: Koopman William J. , Farrar John J. , Oppenheim Joost J. , Fuller-Bonar Janet , Dougherty Suanne 
Published: December 2022

Abstract
Human mixed leukocyte supernatants contain thymocyte proliferative activity (TPA) and a low m.w. helper factor, designated HP-1, which is capable of partially restoring the antibody response of T cell-deficient adherent murine spleen cells to the thymic-dependent antigen, SRC. TPA and HP-1 appear to have a comparable m.w. (14,000 to 14,500 daltons) by Sephadex gel filtration column chromatography. Furthermore, HP-1 and TPA exhibit similar patterns of heterogeneity on DEAE-cellulose chromatography, elute together on CM-cellulose chromatography, and manifest identical patterns of migration on polyacrylamide gel electrophoresis. These data suggest that the TPA and HP-1 activities reside in either the same molecule(s) or in different molecules with identical charge/mass ratios. Furthermore, the results support the hypothesis that the helper activity of HP-1 is derived from its capacity to activate T and/or pre-T cells.
Release of Phospholipids from Complement-Mediated Lesions on the Surface Structure of Escherichia Coli
Authors: Inoue Kozo , Kinoshita Taroh , Okada Mariko , Akiyama Yoko 
Published: December 2022

Abstract
When varying numbers of sensitized, 14C-labeled bacteria were treated with a certain amount of complement, in a fixed reaction volume, 14C compounds were liberated into the surrounding medium in proportion to the number of the bacteria, whereas the amount of the phospholipids liberated was constant regardless of the number of the bacteria even in the range of relative excess of complement. Since it is conceivable that a certain amount of complement might form a fixed number of lesions on the surface of all the sensitized bacteria, the amount of the liberated phospholipids seems to be proportional to the number of complement lesions.
The 14C-materials released from complement-attacked bacteria were analyzed by isopycnic sucrose density gradient ultracentrifugation and they were mainly free phospholipids and other smaller molecules. A small amount of the smaller membrane proteins were also released as revealed by acid and SDS-polyacrylamide gel electrophoresis.
These results suggest that the release of phospholipids is due to the displacement of membrane lipids by the complexes of the late acting complement components during their insertion into the membrane lipid bilayer.
Inhibition of Human Lymphocyte-Mediated Mitogen-Induced Cytotoxicity of Murine L-929 Cells by Heterologous Anti-Human Lymphotoxin Antisera In Vitro
Authors: Hiserodt John C. , Granger Gale A. 
Published: December 2022

Abstract
Heterologous anti-human lymphotoxin (LT) antisera have been employed to investigate the role of LT in mitogen-(Con-A, PHA) induced destruction of murine L-929 cells by human lymphocytes in vitro. These various antisera will effectively neutralize human LT molecules associated with the stable (70 to 90,000 dalton) α-LT class of cytotoxin (anti-α-LT), the more unstable (35 to 50,000 dalton) β-LT class of cytotoxins (anti-β-LT), and antisera which will neutralize all classes of these cytotoxins in vitro, anti-whole supernatant (anti-W.S.). These anti-LT sera will greatly inhibit lysis of L-929 cells by using mitogen-activated human effector lymphocytes in vitro. This blocking was shown to be mediated by whole serum, purified IgG, or IgG-Fab fragments, which had been extensively absorbed with bovine serum, human serum, mitogens, and normal human lymphocytes. Inhibition of lysis was not apparently due to interference with either lymphocyte-target cell contact or lymphocyte activation step(s). The blocking effects of these sera were also shown to occur during the lymphocyte-independent phase of the lytic reaction. These data support the concept that the lymphocyte deposits an LT-like effector molecule on the target-L cell surface during the lymphocyte-dependent phase, which mediates cell lysis at a later time during the lymphocyte-independent phase.
Cyclic Nucleotide Changes in Human Neutrophils Induced by Chemoattractants and Chemotactic Modulators
Authors: Hatch Gary E. , Nichols William K. , Hill Harry R. 
Published: December 2022

Abstract
Two classes of agents have effects on the chemotactic response of human neutrophils. Chemoattractants such as activated complement components, E. coli culture filtrates (BF) and the recently discovered N-formylmethionyl peptides, initiate directed movement, whereas chemotactic modulators enhance or depress cell movement initiated by chemoattractants. We and others have previously shown that cyclic AMP (cAMP) depresses neutrophil migration toward BF whereas cyclic GMP (cGMP) enhances the same process. In the present study, we examined the effects of several chemoattractants and chemotactic modulators on neutrophil levels of cGMP and cAMP. Trypsinized human complement, the E. coli BF and the synthetic peptide, formylmethionylalanine stimulated the accumulation of neutrophil cGMP (40 to 70% average increase) but had little effect on cAMP concentrations. The enhancing chemotactic modulators — phenylephrine, prostaglandin F2α, carbachol, and phorbol myristate acetate — also produced small (19 to 34%) but significant increases in PMN cGMP levels. In contrast, two agents which inhibit the chemotactic response, isoproterenol and prostaglandin E1, significantly elevated cAMP concentrations in PMN.
These results suggest that the ability to elevate cGMP is inherent in the action of both chemoattractants and enhancing chemotactic modulators. Increases in cAMP appear to be correlated with inhibition of chemotaxis.
Murine Plasma Cells Secreting More Than One Class of Immunoglobulin Heavy Chain
Authors: Neiders Mirdza E. , Morse Herbert C. , Lawton Alexander R. , Asofsky Richard 
Published: December 2022

Abstract
SAMM 368, a plasmacytoma which produces IgA-κ and IgG2b-κ was established in vitro from primary explants or after animal passage. The 9 lines that were established produced both paraproteins. The production of both immunoglobulins by single cells was demonstrated by immunofluorescent staining and cloning. Continuous culture of 3 parent lines for 18 months and 11 cloned lines for periods from 5 to 7 months demonstrated that double production is a stable characteristic of this plasmacytoma.
Two single paraprotein-producing varients (IgG2b or IgA) were derived when cells were cultured in the presence of Fungizone.
Chromosomal analysis of SAMM 368 indicates that this double producing tumor has a modal number similar to those observed in myelomas producing a single immunoglobulin class.
A Possible Difference in the Heterogeneity of the Heavy and Light Chains from a Rabbit Anti-P-Azobenzoate Antibody Preparation
Authors: Wang Lom-Seng , Grzyb Kathleen T. , Friedenson Bernard 
Published: December 2022

Abstract
CNBr cleavage of rabbit heavy (H) chains leads to the formation of a fragment, C-1, which consists of the N-terminal half of the H chain. Fragment C-1 is cleaved at methionyl residues but held together by intrachain S-S bonds so that smaller fragments can be liberated by total reduction and alkylation. In the case of the C-1 fragment from an anti-p-azobenzoate antibody preparation, which has a light (L) chain of markedly restricted heterogeneity, total reduction and alkylation liberated seven major fragments in good yield. The N-terminus of two of these fragments corresponds to position 35 of the H chain but their N-terminal sequences are clearly different. The H chain regions represented by the other fragments implied that they were derived from H chains having different distributions of methionyl residues. This hypothesis was supported by isolating six different antibody components from the antibody preparation by isoelectric focusing and then digesting them with CNBr. Comparison of the products showed that the six components all appeared to behave differently. These results are interpreted as suggesting that the process whereby H and L chains are paired in vivo may not be completely specific and may provide a simple means of generating a significant contribution to antibody diversity.
The Interaction of Immunoglobulin Heavy and Light Chains in the Absence of the VH Domain
Authors: Levo Yoram , Recht Bernard , Michaelsen Terje , Franklin Edward C. , Frangione Blas 
Published: December 2022

Abstract
Recent studies of the µ- and κ-chains of the first patient (GLI) with µHCD indicated that the observed defect was the result of the failure of assembly of the intact κ-chain to the µ-chain, which lacked the VH domain but had the CH1 Cys normally linked to the light chain. To explore the possibility that the VH region is necessary for the formation of the HL disulfide bond, in vitro studies were performed with GLI µ- and κ-chains and with the CH1 domain and κ-chain derived from an IgG3 myeloma protein, KUP, which yields separate VH, CH1, and κ-chains after papain digestion and reduction. The proteins were reduced and allowed to reoxidize, and the combination products were assessed by gel chromatography under dissociating conditions by SDS-PAGE and by immunoprecipitation techniques. The results suggest that, although in vitro covalent and noncovalent combinations are possible between intact light chains and their autologous heavy chains even in the absence of the VH domain, the efficiency is less than that when the intact Fd region is used. Hence, it seems likely that lack of VH alone is not sufficient to explain the failure of assembly observed in µHCD.
Colonic Tumor Membrane-Associated Glycoprotein: Isolation of Antigenically-Active Peptides after Chemical Cleavage
Authors: Leung J. P. , Eshdat Y. , Marchesi V. T. 
Published: December 2022

Abstract
A membrane-associated glycoprotein fraction, referred to as CEA-M was isolated from human colonic tumor tissue by sodium dodecyl sulfate extraction of membrane fragments followed by wheat germ agglutinin affinity chromatography, Bio-Gel A-1.5 gel filtration and preparative slab gel electrophoresis. With a m.w. of approximately 200,000, isoelectric point of about 4.2 and carbohydrate:protein ratio of 2:1, this glycoprotein has physiocochemical and antigenic similarities to carcinoembryonic antigen, CEA. Immunochemical studies have shown that antiserum developed for this glycoprotein possesses relative specificity for human colonic carcinomas.
Chemical cleavage of this glycoprotein by 2-nitro-5-thiocyanobenzoic acid resulted in three major Coomassie Blue and two periodic acid Schiff stainable fragments (one of which stains with both). It was found that one of the glycopeptides, labeled as TA, isolated by affinity and covalent chromatography, contained 77% carbohydrates and possessed antigenic determinants recognized by at least 70% of the antibody population raised against the total glycoprotein fraction; purified antibodies to this region of the molecule seem promising for the development of a specific assay for gastrointestinal tumors.
Haplotype Preference in Lymphocyte Differentiation
Authors: Skidmore Barry J. , Katz David H. 
Published: December 2022

Abstract
An experimental protocol was designed to study the regulatory activity of carrier-specific F1 hybrid T cells prepared by immunization of unprimed thymocytes within the environment of one or the other of the parental haplotypes. Thus, normal (BALB/c × A/J) F1 (CAF1) thymocytes were transferred into irradiated CAF1 hybrids or parental A/J or BALB/c recipients and primed to KLH. The resulting KLH-specific activated T cells (ATC) were then co-transferred with DNP-specific B cells obtained from CAF1, BALB/c or A/J donors into irradiated CAF1 recipients which were then secondarily challenged with DNP-KLH. The result of this type of experiment revealed that KLH-primed CAF1 ATC primed in a CAF1 recipient provide comparable helper activity for DNP-primed B cells obtained from either parent or from F1 donors. In contrast, CAF1 ATC primed in parental A/J recipients were found to cooperate considerably better with B cells derived from A/J than from BALB/c donors, and vice-versa in the case of CAF1 ATC primed in parental BALB/c recipients. The crucial, and unexpected, observation was that CAF1 ATC prepared in either parental strain failed to provide adequate helper activity for CAF1 B cells.
These findings suggested the possibility that during the course of priming of F1 T cells in the environment of one of the parents: 1) helper T cells are generated capable of preferentially cooperating with B cells of the same parental haplotype as used for priming; and 2) suppressor cells are generated capable of preferentially interacting with lymphoid cells bearing the opposite parental haplotype. Indeed, strong evidence was found that suppressor cell activity directed against the opposite parental haplotype does exist in populations of CAF1 ATC prepared in either parental strain, as shown by the capacity of such ATC to inhibit the cooperative response between conventionally primed CAF1 spleen cells and DNP-primed B cells bearing the relevant parental haplotype. Moreover, CAF1 thymocytes exposed in situ to low-dose ionizing irradiation before priming manifested even greater suppressive activity measured in this manner.
These observations can be most readily understood by the concept that a population of lymphocytes heterozygous at the major histocompatibility locus consists, either before or after antigen encounter, of separate populations of regulatory lymphocytes, one of which is genetically restricted in its capacity to interact with lymphoid cells bearing one of the parental haplotypes, and a second which is genetically restricted to interact only with lymphoid cells possessing the opposite parental haplotype. The basis of this cellular dichotomy may involve the “restricted expression” of cell interaction (CI) genes and their molecular products in these respective lymphoid subpopulations.