bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tumor promoters in conjunction with calcium ionophores mimic antigenic stimulation by reactivation of alloantigen-primed murine T lymphocytes.
Authors: Isakov N , Altman A 
Published: December 2022

Abstract
Antigen binding to its specific receptor on T cells initiates a series of intracellular events that result in cell differentiation, activation, and clonal expansion. However, the mechanism by which these antigen-occupied receptors induce the transmembrane signal transduction needs clarification. Because this mechanism appears to involve an increase in intracellular free Ca2+ concentration and activation of protein kinase C (PKC), we tested the effect of Ca2+ ionophores and PKC activators on alloantigen-specific primary mixed leukocyte culture cells. Both calcium ionophores, A23187 and ionomycin, in conjunction with 12-O-tetradecanoylphorbol 13-acetate (TPA) mimicked the effect of antigen or interleukin 2 (IL 2) by inducing strong proliferative and alloantigen-specific cytotoxic responses. In addition, Ca2+ ionophore and TPA induced IL 2 receptor expression and IL 2 secretion. The capacity of other phorbol esters or a non-phorbol ester tumor promoter (teleocidin) to replace TPA in induction of cell activation correlated with their ability to bind to and to activate PKC. In addition, the synergistic effect of Ca2+ ionophore and TPA was blocked by either a Ca2+ chelator (EGTA) or cAMP, which is thought to inhibit phosphatidylinositol metabolism. To determine whether the induction of this cytotoxic activity was mediated by a direct effect of Ca2+ ionophore and TPA on cytotoxic T (Tc) cells or was secondary to IL 2 secretion by activated helper T (Th) cells, we tested the effect of Ca2+ ionophore and TPA on isolated populations of cloned, alloantigen-specific Th and Tc cells. Both agents induced cell proliferation and IL 2 production by Th cells, but not by Tc cells. Activation of mixed clones of Th and Tc cells, but not of Tc cells alone, resulted in cytotoxic activity, an effect that could be blocked by anti-IL 2 receptor antibodies. The results thus demonstrate that an increased concentration of intracellular Ca2+ in conjunction with PKC activation can bypass the signal provided by antigen-receptor interaction on Th cells, but does not substitute for IL 2 in activating cytotoxicity by isolated Tc cells.
Growth and differentiation in vitro of the accumulating Lyt-2-/L3T4- subset in lpr mice.
Authors: Budd R C , MacDonald H R , Lowenthal J W , Davignon J L , Izui S , Cerottini J C 
Published: December 2022

Abstract
Mice bearing the recessive gene lpr develop an autoimmune syndrome associated with a massive lymphadenopathy, both of which are age and thymus dependent. The predominant accumulating cells in lymphoid tissue of lpr/lpr mice are Thy-1+ but express neither of the mature T cell markers, Lyt-2 or L3T4. We have purified this Lyt-2-/L3T4- subset and examined its phenotype. These cells are not actively cycling, do not express interleukin-2 (IL 2) receptors nor significant levels of antigen receptor, but do express the B cell marker B220. In vitro growth conditions were examined for the lpr Lyt-2-/L3T4- subset. By using a combination of phorbol ester and IL 2, these cells acquired transient expression of IL 2 receptors and grew in an IL 2-dependent manner. Furthermore, these proliferating cells underwent differentiation to a more mature T cell phenotype, with loss of cell surface B220 and acquisition, by a portion, of antigen receptor and Lyt-2. The possible parallels with normal T cell maturation are discussed.
A restricted human antitetanus clonotype shares idiotypic cross-reactivity with tetanus antibodies from most human donors and rabbits: reactivity with antibodies of widely differing electrophoretic mobility.
Authors: Hoffman W L , Strucely P D , Jump A A , Smiley J D 
Published: December 2022

Abstract
Antitetanus antibodies from each of 20 hyperimmunized human donors were isolated on a tetanus immunoadsorbent, eluted with acidic buffer, and examined by isoelectric focusing (IEF). There was electrophoretic restriction, as determined by IEF, in the IgG of only 20% of the purified antibodies studied. The remaining 80% showed a more diffuse polyclonal spectrotype. Several IEF bands from the most electrophoretically restricted sample were isolated and used to immunize rabbits. Virtually every IgG-IEF band in the antitetanus antibodies of the original donor shared idiotypic cross-reactivity as detected by one or more of the three rabbit anti-Id reagents, even though major qualitative differences in binding from one rabbit anti-Id reagent to another were noted. Antitetanus antibodies of each of the 20 donors were separated by IEF and transferred to a nitrocellulose membrane. By using a sensitive and specific ELISA detection method, cross-reactivity was detected with the rabbit anti-Id reagents in 1 to 50% of the antitetanus antibodies of individual donors. This cross-reactivity was greater than 10% in 15 of the 19 antisera studied. In addition, these cross-reactive antibodies had very different electrophoretic mobility. Binding of the rabbit anti-Id reagents to the tetanus antibodies was almost completely blocked by pretreatment with soluble tetanus toxoid antigen. This idiotypic cross-reactivity with antibodies of different electrophoretic mobility from the same and unrelated donors suggests sharing among these antibodies of one or more of the germ-line DNA-encoded hypervariable regions present in the antibody-combining site.
In vitro immunization of human lymphocytes. I. Production of human monoclonal antibodies against bombesin and tetanus toxoid.
Authors: Ho M K , Rand N , Murray J , Kato K , Rabin H 
Published: December 2022

Abstract
A procedure for in vitro sensitization of human lymphocytes against bombesin conjugated to tetanus toxoid (BTT) is described. Bombesin is a tetradecapeptide associated with small cell lung carcinoma. We found that antibody responses against bombesin as well as tetanus toxoid could be generated in vitro by culturing nylon-separated human splenic lymphocytes for 6 days with lipopolysaccharide, phytohemagglutinin-activated lymphocyte supernatants, human AB serum, and bombesin conjugated to tetanus toxoid. Cells sensitized by this procedure were fused to murine myeloma cells, NS-1. The specificities of resulting hybrids were analyzed by enzyme-linked immunoassays and competitive inhibition experiments. Hybrids secreting anti-bombesin (IgM) or anti-tetanus toxoid (IgM or IgG) were obtained. The ratio of IgG to IgM antibodies against tetanus toxoid could be increased by using antigen coupled to Sepharose beads. The sensitization procedure described here offers a system for the study of antigenic stimulation of human B lymphocytes in vitro and for the production of human monoclonal antibodies with the desired specificities.
Lipopolysaccharide (LPS) stimulates fresh human monocytes to lyse actinomycin D-treated WEHI-164 target cells via increased secretion of a monokine similar to tumor necrosis factor.
Authors: Chen A R , McKinnon K P , Koren H S 
Published: December 2022

Abstract
We have studied the effects of lipopolysaccharide (LPS) on tumoricidal activity of human monocytes freshly isolated from peripheral blood. Actinomycin D-treated WEHI-164 cells were used as targets because they are NK insensitive and are lysed rapidly by monocytes in 6-hr 51Cr-release assays. Monocytes exhibited significant spontaneous activity without endotoxin. Monocytes either pretreated for 1 hr with LPS or assayed in the presence of LPS exhibited 100- to 1000-fold increased cytolytic activity. A half-maximal response was observed with 100 pg/ml LPS. Lipid A was as effective as intact LPS but required slightly higher doses. Monophosphoryl lipid A had no effect. Supernatants of monocytes cultured 5 hr contained sufficient cytolytic activity to account for levels of cytolysis mediated by monocytes directly. Doses of LPS from 10 pg/ml to 10 micrograms/ml produced parallel increases in cell-mediated and supernatant-mediated lysis. Lymphocytes did not produce cytolytic supernatants. Cytolytic activity appeared in monocyte supernatants after 30 min and peaked after 4 to 7 hr regardless of the LPS concentration; longer incubation led to a loss of activity. Cytolytic activity was heat labile and trypsin sensitive, and was recovered from Sepharose S-200 columns in a single peak with an apparent m.w. between 25,000 and 40,000. Actinomycin D or cycloheximide treatment of monocytes before the addition of LPS inhibited cytolytic monokine production. Cytolytic monokine activity was partially neutralized by specific rabbit antisera to human tumor necrosis factor (TNF). We conclude that, although fresh human monocytes exhibit spontaneous tumoricidal activity, LPS is a potent activating agent. Its stimulatory effects depend on new transcription and translation and are mediated by enhanced secretion of a cytolytic monokine similar to TNF.
Sequence similarities and cross-idiotypic specificity of L chains among human monoclonal IgM kappa with anti-gamma-globulin activity.
Authors: Goñi F , Chen P P , Pons-Estel B , Carson D A , Frangione B 
Published: December 2022

Abstract
The complete amino acid sequence of five light chain variable (V) regions of human monoclonal IgM kappa rheumatoid factors (RF) was determined, and their cross-reactive idiotypes (CRI) were characterized with antibodies induced by immunization with synthetic peptides PSL2 and PSL3, corresponding to the second and third complementarity-determining regions (CDR) of the SIE light chain. Together with two additional RF studied previously, all seven RF belong to the V kappa IIIb sub-subgroup. The region encoded by the V kappa gene segment (positions 1 to 95) in all seven proteins was virtually identical in primary structure, whereas the sequence from positions 96 to 108 defined the usage of the J kappa 1 gene in three proteins and the J kappa 2 gene in four of them. Position 96 contributed by the recombination of the V kappa and J kappa gene segments showed the presence of four different amino acid residues. Both anti-PSL2 and anti-PSL3 bind efficiently to all separated L chains when analyzed by the Western blot technique, and the binding was inhibited specifically by the corresponding peptides. The results reveal that the majority of human IgM-RF light chains are derived from a single germ line V kappa gene or a family of closely related V kappa III germ line genes, and express two "primary structure-dependent" CRI, which are largely dependent on the amino acid sequence of the second and third light chain CDR.
Binding of histamine and histamine analogs to lymphocyte subsets analyzed by flow cytometry.
Authors: Muirhead K , Bender P , Hanna N , Poste G 
Published: December 2022

Abstract
The binding of histamine, 4-methylhistamine (a histamine type 2 receptor agonist), cimetidine (a histamine type 2 receptor antagonist), and telemethylhistamine (an inactive analog) to human peripheral blood mononuclear cell subsets was investigated by flow cytometry by using conjugates of these ligands coupled to fluorescein-labeled human serum albumin. Our results indicate that binding of fluorescent protein conjugates of histamine and its analogs does not selectively identify a lymphocyte subset(s) that mediates the immunomodulatory effects of histaminergic ligands. Conjugates with both low (2.5 to 2.8:1) and high (28 to 57:1) ligand to protein coupling ratios were used. No binding above background could be detected for the low mole ratio reagents. The high mole ratio reagents were bound by 95 to 99% of all lymphocytes when used at ligand concentrations of 50 microM or greater. At lower ligand concentrations, the number of lymphocytes exceeding a set fluorescence threshold was decreased, but fluorescence distributions remained unimodal at all concentrations used (1 to 500 microM). Monocytes also bound the high mole ratio reagents and gave rise to a second high-intensity peak in the fluorescence distribution unless they were excluded by other means. Levels of conjugate binding detected by flow cytometry did not parallel ligand potencies at classical histamine type 2 receptors; at equivalent ligand concentrations, approximately equal amounts of histamine or 4-methylhistamine conjugate were bound per lymphocyte, and only 30% less telemethylhistamine conjugate was bound. Competition with free ligands (10(2)- to 10(4)-fold excess histamine, 4-methylhistamine, cimetidine, or telemethylhistamine) did not significantly decrease the level of binding observed for the high mole ratio reagents at bound ligand concentrations of 1 to 25 microM. Dual staining with fluorescein-labeled conjugate and phycoerythrin-labeled monoclonal antibodies Leu-3ab (anti-helper T), Leu-2a (anti-suppressor T), Leu-M3 (anti-monocyte), or anti-HLA-DR (B cells and monocytes) was also carried out. The extent of conjugate binding to helper and suppressor cells was identical for each of the ligands used, but higher levels of conjugate binding were seen for monocytes and B cells than for T cells in every case. Our data do not exclude the possibility of enhanced conjugate binding to small numbers of activated (HLA-DR positive) T cells that might be involved in mediation of histamine effects.(ABSTRACT TRUNCATED AT 400 WORDS)
Organization of rabbit immunoglobulin genes. I. Structure and multiplicity of germ-line VH genes.
Authors: Gallarda J L , Gleason K S , Knight K L 
Published: December 2022

Abstract
Two rabbit germ-line VH gene segments have been isolated from a recombinant phage DNA library. Nucleotide sequence analysis indicates that both of the genes share structural and regulatory features common to mouse and human VH genes, although one appears to be a pseudogene. Comparison of the protein sequences encoded by these genes to the protein sequences of rabbit immunoglobulin V regions indicates that both genes encode VH a-negative-like molecules. Quantitative genomic blot analysis with a VH probe capable of recognizing most, if not all, germ-line VH genes indicates that there are approximately 100 VH genes in the haploid genome of rabbits. The average spacing between the germ-line VH genes was determined to be approximately 6 kb. The molecular basis for the allelic inheritance of rabbit VH allotypes is discussed in view of the structural organization of germ-line VH genes.
Cytotoxic granules from killer cells: specificity of granules and insertion of channels of defined size into target membranes.
Authors: Criado M , Lindstrom J M , Anderson C G , Dennert G 
Published: December 2022

Abstract
The channel-forming polyperforins P1 and P2 are thought to be formed from the contents of dense core vesicles of cytolytic effector cells. To test this hypothesis, granules from various cytotoxic effector cells were assayed for cytolytic activity on nucleated or unnucleated targets. The results show that in general, granules from cytolytic effector cells are cytolytic, whereas granules from noncytotoxic cells are not. Cytotoxicity of granules is not specific, but there appears to be a preference in that nucleated targets are lysed better than are erythrocytes by granules from T killer or natural killer cells. Granules from CTLL-2, however, preferentially lyse erythrocyte targets. This cell line has been in culture for a long period of time and has lost its cytotoxicity. We tested whether granules from CTLL-2 caused formation of transmembrane pores in erythrocyte target membranes. We found that granule- and complement-induced lesions have similar pore sizes. They are big enough to allow the total release of alpha-bungarotoxin, an 8000 Mr polypeptide with dimensions of 4 X 2.5 nm. Larger molecules are released partially or not at all. Under acidic conditions (pH 5.4) granules do not permeabilize target membranes. This may suggest a pH-dependent control mechanism in the formation, insertion, or function of polyperforin channels, in addition to a previously recognized Ca2+-dependent mechanism. Permeabilization of lipid vesicles by granules was studied to explore what the molecular requirements for channel insertion into membranes may be. Release of alpha-bungarotoxin induced by granules was observed in liposomes made of soybean lipid with or without cholesterol, suggesting that no membrane component other than lipid is required for the insertion of polyperforins, and that the action of polyperforins does not require other mechanisms in the target cell. When pure lecithin from soybean and egg, or synthetic phosphatidylcholines were used, slower release or no release of macromolecules was observed. We suggest that some kind of lipid specificity is required for perforin action. This may be related to the hydrophobic region of the lipid bilayer rather than to the polar portion, because different lecithins with varying fatty acid composition gave similar results.
T cells in B cell chronic lymphocytic leukemia. II. Lack of antigen-specific T suppressor cells and their progenitors.
Authors: Bloem A C , Heijnen C J , Bast B J , Ballieux R E 
Published: December 2022

Abstract
Nylon wool-purified T cells (Tn) of two patients with chronic lymphocytic leukemia of the B cell type were phenotyped and tested in various assays for antigen-specific T helper (Th), T suppressor effector (Tse), T suppressor precursor (Tsp), and T suppressor inducer (Tsi) function. Antigen-specific Th as well as Tsi activity could be effectively generated. Although phenotypically CD8+ T cells, carrying the receptor for the Fc part of IgG, were present in mononuclear blood cells and Tn fractions, no antigen-specific Tse cell activity could be induced. In addition, Tsp cells were found to be functionally absent. These findings are discussed in relation to a tumor-induced limited heterogeneity within the T suppressor (Ts) cell compartment.
Specific sensitization of Lyt-1+2- T cells to spleen cells modified by the drug D-penicillamine or a stereoisomer.
Authors: Nagata N , Hurtenbach U , Gleichmann E 
Published: December 2022

Abstract
A mouse model for assessing the sensitization of T cells to the drug D-penicillamine (D-Pen) has been established. Mice were primed with D-Pen in vivo and the secondary response of specific T cells was measured in a proliferative assay in vitro. Priming was achieved by injecting either free D-Pen or, more effectively, D-Pen in complete Freund's adjuvant at the base of the tail. After 7 to 9 days, the draining lymph node cells (responder cells) were restimulated in vitro with syngeneic spleen cells that had been preincubated with D-Pen for 20 to 22 hr and washed (D-Pen-SC). The thiol (-SH) group of D-Pen was required for generating effective stimulator cells; other thiol compounds, however, or heavy metals (Hg, Au) were unable to generate cross-reacting stimulators on incubation with spleen cells. Although D-Pen-SC proved to be good stimulator cells, thymocytes and mouse erythrocytes, after having been preincubated with D-Pen, completely failed to stimulate. The proliferating responder cells were Lyt-1+2- T cells that were highly specific for D-Pen-SC and were even capable of distinguishing between the two stereoisomers D-Pen and L-Pen. The splenic T cells of recipient mice were effectively primed by injecting D-Pen-SC, but not free D-Pen, via the i.v. route. These findings indicate that D-Pen can act as a hapten for specific T cells when presented on the surface of appropriate stimulator cells. Conceivably, if D-Pen were able to generate effective stimulator cells in vivo, this could lead to T cell reactions comparable to those in the graft-vs-host reaction (GVHR). We discuss the possibility that the GVH-like adverse immunologic side-effects of D-Pen in patients may have a GVHR-like pathogenesis.
The immunopathology of chronic experimental allergic encephalomyelitis induced in rabbits with bovine proteolipid protein.
Authors: Sobel R A , van der Veen R C , Lees M B 
Published: December 2022

Abstract
The role of myelin proteolipid apoprotein (PLP) in the central nervous system (CNS) immune response of rabbits has been investigated by analyzing the immunopathology of chronic experimental allergic encephalomyelitis (EAE) induced by sensitization with PLP. Clinical disease occurred in seven out of nine rabbits sensitized with bovine PLP and monitored for up to 6 mo. Positive delayed hypersensitivity skin test reactions to PLP occurred in all but one of the PLP-sensitized animals. All PLP-sensitized animals had meningeal and CNS parenchymal inflammation that correlated with disease severity. Serial blood samples were stained with a panel of antibodies to rabbit T and B cells, as well as Ia, and large and small mononuclear cell populations were analyzed by flow cytometry. Peripheral leukocyte population staining did not correlate with clinical signs or sensitization to PLP. Cryostat CNS tissue sections were stained with the same set of antibodies by using an immunoperoxidase technique, and positive cells and vessels were counted. T cells and macrophages were numerous and in equal numbers in perivascular parenchymal inflammatory infiltrates, whereas B cells were less numerous (p less than 0.001). T cells also diffusely infiltrated the parenchyma. Most perivascular inflammatory cells and many scattered parenchymal cells were Ia+; Ia vascular expression was increased over controls (p less than 0.001), and also correlated with disease severity. The immunopathology of this chronic EAE model is the same as that of whole CNS tissue- and myelin basic protein-induced EAE in other species, and is similar to that of multiple sclerosis. Cellular immune responses to PLP may therefore contribute to systemic and in situ responses in CNS tissue demyelinating diseases.
Spontaneous production of a suppressor factor by the human macrophage-like cell line U937. I. Suppression of interleukin 1, interleukin 2, and mitogen-induced blastogenesis in mouse thymocytes.
Authors: Fujiwara H , Ellner J J 
Published: December 2022

Abstract
The human macrophage-like cell line U937 spontaneously produced a nondialyzable factor that inhibited interleukin 1 (IL 1), interleukin 2 (IL 2), and phytohemagglutinin (PHA)-induced blastogenesis in mouse thymocytes. The suppression by U937 supernatant factor occurred independently of the concentration of IL 1 or PHA, indicating that it was noncompetitive. The U937 suppressor factor was not cytotoxic for thymocytes, nor did it affect the spontaneous proliferation of T lymphoblastoid cell lines and U937. Physicochemical characterization showed that the U937 suppressor factor was nondialyzable, partially inactivated by heat treatment (56 degrees C), ammonium sulfate (67% saturation) precipitable, sensitive to pH 2.5, and resistant to freeze-thawing. Molecular weight of the factor inhibiting co-mitogenic IL 1 activity was approximately 85,000, as estimated by gel filtration. The U937 cell line may provide a model for the study of mechanisms and mediators of immunosuppression by mononuclear phagocytes.