bluuebunny/crossref_metadata_2025_split huggingface dataset:
Activation of Human Complement by Liposomes: A Model for Membrane Activation of the Alternative Pathway
Authors: Cunningham Carolyn M. , Kingzette Mae , Richards Roberta L. , Alving Carl R. , Lint Thomas F. , Gewurz Henry 
Published: December 2022

Abstract
Liposomal model membranes were found to activate the alternative pathway of human complement. Activation was measured by C3 conversion and component consumption in serum that had been incubated with liposomes. C3 conversion did not require C1 or C2 of the classical pathway, since it was observed in serum from a C1r-deficient patient, serum from a C2-deficient patient, and normal serum in buffer containing EGTA and MgCl2. The incubation of liposomes with C2-deficient serum resulted in consumption of components C3 through C9 with no consumption of C1 or C4 in a profile typical of alternative pathway activation. The reaction was further shown to require alternative pathway factor D, and to be independent of antibody.
Activation of the alternative pathway was dependent on the membrane composition of the liposomes. A positive charge was required for liposomes to produce C3 conversion. Liposomal cholesterol concentration and phospholipid fatty acyl chain length and unsaturation all influenced activation, suggesting the importance of membrane fluidity. Positively charged liposomes containing dimyristoyl phosphatidylcholine and cholesterol required the presence of certain glycolipids for C3 conversion. The activation of the alternative complement pathway by liposomes of defined membrane composition may provide a suitable model for the study of alternative pathway activation by cellular membranes.
Lipid Synthesis: An Indicator of Antigen-Induced Signal Transduction in Antigen-Binding Cells
Authors: Kenny James J. , Martínez-Maza Otoniel , Fehniger Thomas , Ashman Robert F. 
Published: December 2022

Abstract
A biochemical parameter of lymphocyte activation, lipid synthesis, has been measured in a purified specific antigen-binding cell population (ABC). ABC isolated from immune and nonimmune animals by sequential centrifugation on buoyant density and sedimentation velocity gradients have a 2- to 7-fold higher rate of 14C-choline incorporation into phospholipid than either unfractionated spleen cells or cells depleted of ABC. Also ABC from immune animals were shown to have a 4- to 7-fold higher rate of 14C-acetate incorporation into their neutral lipids than nonbinding controls.
The elevated lipid synthesis seen in both nonimmune SRBC-ABC and TNP-SRBC ABC indicates that antigenic contact via the B cell immunoglobulin receptor results in signal transduction and activation of the specific receptor-bearing lymphocyte population. Binding of the same particle (SRBC) to B cells via their Fc receptors did not regularly result in activation of lipid synthesis. The magnitude of the increased lipid synthesis in ABC populations approached that seen in LPS-stimulated spleen cells. We propose that the measurement of early activation events in purified ABC may be a more appropriate criterion for antigen-induced signals than later events such as thymidine incorporation or antibody secretion.
Cross-Reactions between Tryptic Polypeptides of Staphylococcal Enterotoxins B and C
Authors: Spero Leonard , Morlock Beverly A. 
Published: December 2022

Abstract
The strong cross-reactions demonstrated for staphylococcal enterotoxins B (SEB) and C1 (SEC1) by measurement of antigen-binding capacity were reflected in well defined polypeptides obtained by limited tryptic digestion from SEB and SEC1. Two antigenic determinants on each enterotoxin were capable of reacting with heterologous antibody, one on the first 57 amino acids and one on the last 150 residues of the polypeptide backbone. The larger, carboxyl terminal polypeptides bound efficiently to homologous antiserum but about two orders of magnitude less efficiently to heterologous antibody. The amino terminal peptides showed only weak homologous binding but nearly comparable heterologous binding. It is proposed that the determinant on the amino terminal polypeptides is largely responsible for the strong reciprocal binding of the intact enterotoxins and that their low antigen-binding capacity is due to a random or a structurally distorted conformation in solution.
Ontogeny of B Lymphocyte Function
Authors: Szewczuk Myron R. , Sherr David H. , Cornacchia Anthony , Kim Young T. , Siskind Gregory W. 
Published: December 2022

Abstract
The responses to one or to two injections of antigen (referred to as “primary” and “secondary” responses, respectively) by lethally irradiated LAF1 mice reconstituted with syngeneic neonatal liver cells plus adult thymus cells are compared with the responses of irradiated mice reconstituted with adult spleen and thymus cells. In every case the primary response by mice reconstituted with neonatal B cells is of restricted heterogeneity of affinity and low average affinity as compared with the response of animals reconstituted with adult spleen as the source of B cells. The secondary responses by mice reconstituted with adult spleen cells are all highly heterogeneous and of high affinity. The secondary responses to Ova, BSA, DNP-BGG, and the F(ab′)2 fragment of HGG by mice reconstituted with neonatal liver are highly heterogeneous and of high affinity, like those of animals reconstituted with adult spleen. In contrast, the secondary responses to HGG and BGG by mice reconstituted with neonatal liver are of low affinity and restricted heterogeneity as compared with the secondary responses of mice reconstituted with adult spleen cells. Thus, the immune responses of immature B cells to heterologous immunoglobulins differ from their responses to other T-dependent antigens. This difference may be related to some property of the Fc portion of the heterologous immunoglobulin. In addition, the data indicate that with most of the antigens studied a high affinity memory B cell population can be selectively expanded in lethally irradiated mice reconstituted with neonatal liver despite the fact that their primary responses lack detectable high affinity PFC. This suggests that the failure of mice reconstituted with neonatal or fetal B cells to produce a high affinity primary PFC response may reflect an inability of the immature B cells to differentiate into antibody-secreting cells.
Cytolytic T Lymphocytes Recognize Alloantigens on Schistosomula of Schistosoma Mansoni, but Fail to Induce Damage
Authors: Butterworth Anthony E. , Vadas Mathew A. , Martz Eric , Sher Alan 
Published: December 2022

Abstract
Murine peritoneal exudate cells rich in cytolytic T lymphocytes (CTL) with specificity for alloantigens were found to adhere specifically to schistosomula, recovered from the lungs of mice, which bear alloantigens on their surface as a result of passive acquisition from the host. The presence of CTL in the adherent cell population was confirmed by a mixed killing reaction, in which it was shown that most of the cells that had adhered to the schistosomula were subsequently able to kill an appropriate tumor target cell. These CTL, however, failed to damage the schistosomula even after prolonged periods of culture (up to 66 hr) at high effector to target ratios. The same organisms were at least partially susceptible to complement-dependent damage by antibody with specificity for the same alloantigens. Furthermore, the same CTL preparations could artificially be induced to adhere to skin-stage schistosomula, which do not bear alloantigens on their surface, by using concanavalin A as a nonspecific binding agent to overcome the requirement for specific recognition of target antigens by the CTL. Such organisms were also insusceptible to CTL-mediated damage, even though they have previously been shown to be damaged by both eosinophils and neutrophils. Reasons for the lack of CTL damage are discussed, and it is emphasized that the adherence reaction provides a new model for examining the early stages of the interaction of CTL with their targets, and for studying the recognition by CTL of antigens that have been passively inserted into a target membrane.
Mast Cell Granule Peroxidase: Location, Secretion, and SRS-A Inactivation
Authors: Henderson William R. , Kaliner Michael 
Published: December 2022

Abstract
Rat peritoneal mast cells contain peroxidase as demonstrated both histochemically and enzymatically. This enzyme is localized to the mast cell granule where it is concentrated along with histamine and superoxide dismutase (SOD). Rat mast cell degranulation initiated by 48/80 produced a significantly larger percentage of net histamine release than of either peroxidase or SOD. Examination of isolated mast cell granule preparations revealed that histamine was readily displaced from the granule upon exposure to physiologic NaCl solutions and that NaCl solutions of sufficient molarity to dissolve the granular matrix were required to solubilize the bulk of peroxidase and SOD. Therefore, we washed 48/80 treated mast cells with hypertonic NaCl solutions in order to partly dissolve the extracellular granules. A 3.9-fold increase in supernatant peroxidase was produced by this washing without an accompanying commensurate increase in histamine or loss of the capacity of the cells to exclude trypan blue. Based upon these observations, there appeared to be three distinct sources of biologically active mediators generated as a consequence of mast cell degranulation: preformed, readily displaced molecules such as histamine and serotonin; newly generated molecules such as slow-reacting substance of anaphylaxis (SRS-A), and the prostaglandins; and granule matrix associated activities such as peroxidase, SOD, heparin, chymotrypsin, and others. Assessment of the molecules released into the supernatant of degranulated mast cells may therefore indicate only a portion of the mediators actually discharged from the mast cell. The granule matrix-associated activities may be transposed more slowly and cause more subtle and delayed responses. Among the potential activities relevant to immediate hypersensitivity is the capacity of the granule to inactivate SRS-A as well as superoxide .
Con A-Inducible Suppression of MLC: Evidence for Mediation by the TH2+ T Cell Subset in Man
Authors: Reinherz Ellis L. , Schlossman Stuart F. 
Published: December 2022

Abstract
Human peripheral lymphoid cells pretreated with Concanavalin A for 48 hr can markedly suppress the proliferative response of untreated autologous lymphoid cells in MLC. Isolation studies with Sephadex G-200 anti-F(ab′)2 affinity chromatography, nylon adherence, and E rosetting indicate that the Con A-induced suppressor cell is a T cell. Further fractionation into TH2+ and TH2- cell subsets with an equine-anti TH2 serum show that both subsets can be activated by Con A to an equivalent degree. After activation only the TH2+ subset can suppress autologous responder cells in MLC. The TH2- subset, which comprises 80% of peripheral human T cells, although induced by Con A to proliferate, cannot itself suppress the MLC response. Nevertheless, the TH2- subset can be shown to modulate the generation of suppressor TH2+ cells at 24 hr but not at 48 hr. These studies support the notion that the Con A-induced suppressor cell is confined to a distinct T cell subset in man and that T-T interactions are important in the overall expression of the immune response.
Regulatory T Cell Subpopulations in Pregnancy
Authors: Chaouat Gérard , André Voisin Guy 
Published: December 2022

Abstract
Previous in vivo experiments have provided evidence of suppressive activity induced by multiple allogeneic pregnancies. The reactivity of maternal spleen cells toward paternal strain alloantigens was investigated by use of MLR microculture technique. A study of the kinetics of the MLR showed an early peak of reactivity (48-hr culture) followed by a decline leading to a decreased reactivity by 96 hr when spleen cells from allogeneically pregnant mice were compared to those of virgin or even isogeneically pregnant mice, suggesting the possible action of MLR regulatory cells. A strong suppression of a H-2k (CBA) anti-H-2a (A/J) or anti-H-2d (C57BL/Ks) MLR was observed when mitomycin-treated spleen cells from CBA mice multiparous by A/J or C57BL/Ks (but not CBA) males were added to the culture. This suppression was abolished by treating the regulatory cell population with anti-ϑ serum plus complement or replacing the 1% normal mouse serum in the medium by a proper anti-idiotypic mouse serum.
Antigenic Properties and Molecular Weights of Murine Leukemia Virus-Binding Proteins
Authors: Baird Stephen M. 
Published: December 2022

Abstract
A murine T lymphoma cell line, WEHI-22, has been studied for the presence of murine leukemia virus-binding proteins and for the presence of cell surface molecules that share antigens with mouse immunoglobulins. With surface radioiodination, detergent disruption, and immunoprecipitation, a 60 to 70,000-dalton molecule has been described that is recognized by chicken anti-mouse immunoglobulin serum. In competition experiments this molecule cross-reacts with highly purified mouse IgM myeloma proteins. A cell surface molecule of similar size can be shown to bind to mouse leukemia viruses. Preprecipitation of the WEHI-22 cell surface material with chicken anti-mouse immunoglobulin removes the material binding to leukemia viruses.
Structural Evidence for a Polymorphic or Allelic form of the Heavy Chain Variable Region
Authors: Latham Claflin J. , Rudikoff Stuart 
Published: December 2022

Abstract
The heavy (H) chains of anti-phosphocholine (PC) antibodies from C57BL/6J and CBA/J were sequenced through the N-terminal 36 residues and compared with previously published sequences of A/J anti-PC antibody and BALB/c PC-binding myeloma proteins T15, M603, and M511. Each of these antibody preparations contained molecules having light (L) chains and idiotypic determinants of T15, M511, and M603 indicating the presence of at least three different anti-PC antibodies in each pool. The structures of the C57BL/6J and CBA/J H chains each revealed a single sequence from positions 1 to 36 (which includes the first complementarity determining region (CDR)), and they were identical. The first CDR was identical to that previously found for BALB/c and A/J indicating that this portion of these antibody molecules is highly conserved throughout inbred mice and is probably critical to PC-binding. A surprising finding was that both C57BL/6 and CBA sequences differed from the BALB/c and A/J sequences at two positions, residue 14 and 16. Since each of these strains differs at the allotype locus, the data indicates that the evolution of allotypy in mice occurred after variable region diversity for these particular genes.
Immune Responses During Human Schistosomiasis Mansoni
Authors: Todd Charles W. , Goodgame Richard W. , Colley Daniel G. 
Published: December 2022

Abstract
Peripheral blood mononuclear cells (PBMN) from chronically infected schistosomiasis mansoni patients responded poorly in vitro to a soluble schistosomal egg antigen preparation (SEA) and moderately well to either soluble worm (SWAP) or soluble cercarial (CAP) antigenic preparations. The responses induced by SWAP or CAP were dramatically increased, in 84 and 92%, respectively, of the 24 chronically infected patients tested, upon removal of adherent/phagocytic (A/P) cells from the original cell populations. In contrast, removal of A/P cells from the PBMN of treated patients, transiently infected patients, and uninfected control subjects did not result in enhanced reactivity to these antigens. Overall, SEA-induced responsiveness of chronically infected patients' cells remained low in spite of A/P cell removal. Lymphocyte transformation induced by phytohemagglutinin-P and Candida albicans extract was not significantly altered by removal of A/P cells in any of the groups tested. The expression of another regulatory system concerned with a nonspecific suppressive influence exerted by SEA was also unaffected by the presence or absence of A/P cells. The previously reported, in vitro, schistosome antigen-specific, serosuppression mediated by sera from most chronically infected patients was effective in the presence or absence of A/P cells. However, serosuppression and A/P cells combined to exert maximum suppression of both the SWAP- and CAP-induced responses of chronically infected patients' cells. The enhanced responses observed after A/P cell depletion represented actual increases in blastogenesis, as determined morphologically, as well as increased incorporation of tritiated thymidine. These studies have demonstrated the presence of immunoregulatory A/P cells in the PBMN cells of chronically infected schistosomiasis mansoni patients which have the capability to suppress lymphocyte blastogenesis induced by the antigenic preparations derived from adult worms and the infectious, cercarial, larval stage of the parasite Schistosoma mansoni.
Hybrid Resistance to BALB/c Plasmacytomas
Authors: Clare Walker Mary , Phillips-Quagliata Julia M. 
Published: December 2022

Abstract
Resistance to the BALB/c plasmacytoma MPC-11 by F1 hybrids between BALB/c and four C57BL/10 congenic resistant strains was abrogated or reduced by 450 rads total body irradiation but was unaffected by intravenous injection of 3 to 4 mg of silica. These results are consistent with the idea that hybrid resistance to MPC-11 depends on an active immune response and is different from Hh-1 controlled hybrid resistance.
Effect of Inhibitors of Arachidonic Acid Metabolism on Mitogenesis in Human Lymphocytes: Possible Role of Thromboxanes and Products of the Lipoxygenase Pathway
Authors: Kelly James P. , Johnson Mary C. , Parker Charles W. 
Published: December 2022

Abstract
Although it is already known that prostaglandins inhibit lymphocyte responses to mitogens the role of other products of arachidonic acid (AA) metabolism has not previously been investigated. Various inhibitors of AA metabolism were studied for their effects on mitogenesis in human lymphocytes, including imidazole, benzylimidazole, N-0164, L-8027, 5, 8, 11, 14 eicosatetraynoic acid, nordihydroguaiaretic acid, indomethacin, and aspirin. Selective or partially selective inhibitors of thromboxane synthesis, such as imidazole, benzylimidazole, N-0164, and L-8027 inhibited the mitogenic response at concentrations that also substantially affect thromboxane B2 synthesis in platelet-free lymphocyte preparations. Since indomethacin failed to reverse the inhibition by imidazole or N-0164, it is probably due to decreased thromboxane synthesis per se rather than secondary increases in prostaglandin synthesis. Eicosatetraynoic acid and nordihydroguaiaretic acid were more effective inhibitors of mitogenesis than of thromboxane synthesis. Since these agents also affect the lipoxygenase pathway, it is possible that part of their action is at this level. Thus, in addition to the inhibitory effects of prostaglandins on mitogenesis, other products of AA metabolism may promote the response.
Interferon-Induced Enhancement of IgE-Mediated Histamine Release from Human Basophils Requires RNA Synthesis
Authors: Hernandez-Asensio Mercedes , Hooks John J. , Ida Shiroh , Siraganian Ruben P. , Louis Notkins Abner 
Published: December 2022

Abstract
Incubation of human leukocytes with certain viruses results in the enhancement of IgE-mediated release of histamine. This enhancement is produced by interferon. The present experiments show that an induction period of 6 to 9 hr and new RNA synthesis are required for interferon to enhance histamine release. This points to the possibility that interferon may exert its antiviral and histamine-release enhancing activities by acting through a common pathway.
Regulation of T Cell Mitogen Activity of Anti-Lymphocyte Serum by a B-Helper Cell
Authors: Norcross Michael A. , Smith Richard T. 
Published: December 2022

Abstract
Rabbit anti-mouse brain antiserum (RaMB) was found to be mitogenic for mouse lymphocytes by using a 3H-thymidine incorporation assay. The mitogenic activity was maximal at 48 hr incubation and was absorbable with brain and T lymphocytes. Specificity was directed toward a Thy-1 like molecule without Thy-1 allotypic restrictions. Mixed populations of lymphocytes from spleen and lymph node were highly responsive to low concentrations of RaMB at which purified subpopulations of T or B lymphocytes were unresponsive. T cell responses could be reconstituted by addition of B-enriched cell subpopulations. Macrophages had no helper effect; rather they inhibited the response even at very low numbers of cells. Proliferative responses in mixed populations involved both T and B cell subpopulations in which the T cell component accounted for 80 to 90%, and the B cell subpopulation about 10 to 20% of net thymidine incorporation. B cell proliferation was not required for the regulatory effect. No B cell helper activity was detectable if F(ab′)2 fragments prepared from RaMB-Ig were used as mitogen. The data suggest that T cell activation by anti-T cell serum first involved ligand-antibody interaction. This is a necessary but insufficient cell surface event to trigger proliferation. A second interaction appears to be required to initiate proliferation. The data suggest that the Fc region of the bound antibody molecule supplies this impetus by engaging the Fc receptor of the B-helper cell.
Regulation of Lymphocyte-Activating Factor (LAF) Production and Secretion in P388D1 Cells: Identification of High Molecular Weight Precursors of LAF
Authors: Mizel Steven B. , Rosenstreich David L. 
Published: December 2022

Abstract
Phorbol myristic acetate (PMA) markedly enhanced the production and secretion of lymphocyte-activating factor (LAF) by the murine macrophage cell line, P388D1. The stimulatory effect of PMA proceeded, in part, via activation of an existing intracellular precursor pool of LAF. This conclusion is based on the observations that 1) the initial stimulatory effect of PMA on LAF production and secretion occurred for at least 4 hr in the presence of two inhibitors of protein synthesis, cycloheximide and puromycin, and 2) higher m.w. aggregate forms of LAF, possessing differing levels of activity, were present in the sonicates of P388D1 cells. Five species of intracellular LAF with approximate m.w. of 220,000, 50,000 to 70,000, 39,000, 26,000, and 13,000 daltons were resolved on a Sephacryl S200 column. The 50,000 and 13,000 m.w. forms exhibited the most LAF activity, the 39,000 and 26,000 m.w. species were significantly less active, and the 220,000 m.w. form was only weakly active. The 13,000 m.w. intracellular LAF exhibited the same charge heterogeneity on DEAE cellulose as the LAF obtained from the culture supernatants of PMA-stimulated cells, suggesting that the charge heterogeneity of LAF is probably not the result of extracellular modification but a characteristic of the intracellular factor. The 50,000 m.w. species could be completely converted to the 26,000 and 13,000 m.w. forms of intracellular LAF at 37°C. The conversion reaction was not mediated by a trypsin or chymotrypsin-like enzyme nor was the reaction inhibited or enhanced by sodium dodecyl sulfate. The reaction was, however, strongly temperature dependent, proceeding with low efficiency at 4° or 25°C. We propose that during the initial stage of macrophage activation (“priming”), the inactive precursor form(s) of LAF is synthesized and stored. Upon exposure of the primed cells to a secondary stimulus such as PMA, the LAF precursor is converted to an active low m.w. form and secreted. This precursor activation process would thus provide a rapid and efficient mechanism for the mobilization and release of relatively large quantities of LAF by primed or activated macrophages.