bluuebunny/crossref_metadata_2025 huggingface dataset:
T cell-dependent mast cell degranulation and release of serotonin in murine delayed-type hypersensitivity.
Authors: Askenase P W , Bursztajn S , Gershon M D , Gershon R K
Published: June 2004

We have previously suggested that the release of serotonin (5-hydroxytryptamine) (5-HT) by local tissue mast cells is required for the elicitation of delayed-type hypersensitivity (DTH) in mice. In the current study, light microscopic radioautographs from animals treated with [3H]5-HT indicated that local mast cells released 5-HT between 6 and 18 h during the evolution of DTH. Ultrastructural examination of mast cells revealed surface activation, indicated by extension of surface filopodia, and degranulation by fusion and exocytosis. Light and electron microscopic studies of the endothelium of postcapillary venules at sites of DTH revealed the development of gaps between adjacent cells. The development of gaps permitted extravasation of tracers that was abolished by depletion or antagonism of 5-HT. Thus mast cells degranulated and released 5-HT in DTH, and this 5-HT acted on local vessels. Recipients of nonadherent, non-immunoglobulin-bearing sensitized lymphocytes also demonstrated similar mast cell degranulation and the formation of endothelial gaps. This indicated that mast cell degranulation and 5-HT release in murine DTH were probably T cell dependent.
Lectin receptors as markers for Trypanosoma cruzi. Developmental stages and a study of the interaction of wheat germ agglutinin with sialic acid residues on epimastigote cells.
Authors: Pereira M E , Loures M A , Villalta F , Andrade A F
Published: June 2004

Trypanosoma cruzi at various stages of maturation and differentiation have been isolated by conventional cellular fractionation procedures and characterized by cell surface markers using 30 highly purified lectins encompassing all known sugar specificities. Cell surface carbohydrates of the various T. cruzi stages were analyzed by agglutination and lectin-binding assays. Specific receptors for wheat germ agglutinin (WGA), Helix pomatia, Sophora japonica, and Bandeiraea simplicifolia lectin II were found only in culture epimastigotes, whereas peanut agglutinin (PNA) sites were present exclusively in amastigotes, those for Phaseolus vulgaris in bloodstream trypomastigotes and amastigotes, and for Wistaria floribunda hemagglutinin predominantly in culture forms of T. cruzi. The N-acetylgalactosamine (DGalNAc)-binding lectin from Bauhinia purpurea agglutinated and inhibited the movement of epimastigotes and bloodstream trypomastigotes, but it only inhibited--without agglutinating--culture trypomastigotes. Because both the agglutination and inhibition of movement were reversed by specific sugar haptens, Bauhinia purpurea sites were present in all the flagellated parasites. On the other hand, PNA sites were detectable on epimastigotes after the cells were treated with sialidase, whereas, at the same time, WGA receptors were completely removed and those for the other sialic acid-binding proteins, Aaptos papillata lectin II and Limulus polyphemus, were partially eliminated; moreover, the activity of Wistaria floribunda hemagglutinin, a DGalNAc-binding lectin, increased 4,000 times. Trypsinization and lyzozyme treatment of epimastigote cells did not significantly affect lectin agglutination or lectin binding. WGA reacted solely with sialic acid residues on epimastigote cell surface with an apparent association constant of 2 x 10(6) M-1, each epimastigote having an estimated average of 3 x 10(6) WGA sites, as determined by binding experiments and a minimum of 7.7 x 10(6) sialic acid residues, as calculated by colorimetric method after sialidase digestion. Evidences are presented that the sialyl residues are rapidly regenerated (in approximately 4 h) and that they, at least for the most part, are not adsorbed from the culture medium. The receptor for the D-mannose-binding lectins (concanavalin A [Con A] and Lens culinaris) must either be on the same carbohydrate moiety having the WGA site, or, if in a distinct molecule, both carrier molecules of Con A and WGA sites must be located close to each other in the plasma membrane of the parasite.
Relative sensitivity of fetal and newborn mice to induction of hapten-specific B cell tolerance.
Authors: Pike B L , Kay T W , Nossal G J
Published: June 2004

Mice were rendered tolerant to the hapten fluorescein (FLU) by a single injection of FLU-human gamma globulin (FLU5HGG) 2-3 d after birth or via the maternal circulation at 14.5 d of fetal life. After 7-9 d, the degree of functional nonresponsiveness induced in vivo among splenic FLU-specific B cells of tolerized mice was assessed by limiting-dilution analysis in vitro, and the serum levels of trace-labeled tolerogen were determined. When tolerogen was introduced before the appearance of any B cells, and was thus present during the pre-B to B cell transition stage, a concentration of 5.4 x 10(-13) M effectively silenced 50% of the clonable anti-FLU PFC precursors; but a similar reduction on newborns required a minimal tolerogen concentration of 1.3 x 10(-10) M, > 300-fold less than has previously been shown to equally affect adult B cells, but at least 240-fold more than in the in utero situation. Neonatally induced tolerance using a relatively high tolerogen dose lasted approximately 12 wk.
Genetic mapping of the ecotropic virus-inducing locus Akv-2 of the AKR mouse.
Authors: Kozak C A , Rowe W P
Published: June 2004

A combination of somatic cell hybridization and standard mendelian breeding techniques was used to map the AKR ecotropic virus inducibility locus Akv-2 to the centromeric end of chromosome 16. This assignment of Akv-2 further emphasizes the endogenous ecotropic retroviruses are inserted at multiple sites in mouse chromosomes.
Mitogen-initiated synthesis and secretion of T cell growth factor(s) by a T-lymphoma cell line.
Authors: Shimizu S , Konaka Y , Smith R T
Published: June 2004

Of 12 T-lymphoma cell lines investigated, one line, EL-4 azgr (Thy-1+, Lyt-1+, Lyt-2-3-,Ia-, T-200+, sIg-, and FcR-) and, to a lesser extent, the parental cell line, EL-4, produced T cell growth factor(s) (TCGF) when stimulated by the T-cell mitogen concanavalin A (Con A). Induced production of TCGF-E was detected by 6 h and maximal at 18-24 h. Purified TCGF-E from this source had an approximately 30,000 mol wt and the biological activity of TCGF produced by whole spleen cells, including: augmentation of T cell-mitogen responses, cytotoxic T lymphocyte (CTL) proliferation support dependence, augmented generation of CTL, lack of strain specificity, and failure to stimulate resting T cells. TCGF-E is neither synthesized or secreted by this lymphoma cell line unless stimulated by Con A. X-irradiation up to 7,000 rad failed to inhibit synthesis and secretion. These observations have a practical application in providing a relatively homogeneous clonal cell product for T cell culture support and for structural and functional studies of the TCGF molecule(s). They suggest also a model for examining mechanisms of triggering production and secretion of a regulatory molecule that controls T cell functions.
Macrophage oxygen-dependent antimicrobial activity. IV. Role of endogenous scavengers of oxygen intermediates.
Authors: Murray H W , Nathan C F , Cohn Z A
Published: June 2004

The activities of the endogenous O2- and H2O2 scavenging enzymes, superoxide dismutase (SOD), glutathionine peroxidase (GP), and catalase, were measured in lysates of the intracellular parasite, Toxoplasma gondii, and in various macrophage populations. During 72 h of cultivation in standard medium alone, the catalase activity of in vivo-activated toxoplasma-immune macrophages (IM) and immune-boosted macrophages (IB) progressively increased by eight- to ninefold, and correlated with the previously observed parallel decline in these cells' antitoxoplasma activity and capacity to release H2O2. SOD and GP activities either remained constant or decreased during this 3-d period. Lymphokine exposure, which preserved the antitoxoplasma activity and oxidative capacity of 48- and 72-h cultures of IB and IM cells, blunted the rise in catalase levels and had no effect on SOD or GP. Inhibition of IB and IM macrophage catalase by aminotriazole maintained toxoplasmastatic activity otherwise lost after 48 h of cultivation. In addition, IB and IM cells from acatalasemic mice contained 20- to 30-fold less catalase, and showed comparatively little decline in either H2O2 release or antitoxoplasma activity during 72 h in culture. In vitro-(lymphokine) activated resident macrophages from normal mice had the highest levels of SOD, GP, and catalase, and these cells failed to kill or inhibit T. gondii despite enhanced extracellular release of O2- and H2O2. Toxoplasmas were also found to contain all three enzymatic scavengers. Aminotriazole inhibition of lymphokine-activated cells' catalase or of toxoplasma catalase was effective in inducing these macrophages to display antitoxoplasma activity. Moreover, and in contrast to normocatalasemic resident cells, those from acatalesemic mice were readily induced by lymphokine to inhibit the replication of untreated virulent toxoplasmas. These results suggest that endogenous O2- and H2O2 scavenging enzymes, which function within both T. gondii and activated macrophages as host cell antioxidant protective mechanisms, may reduce the effectiveness of phagocyte antimicrobial activity. Thus, the presence of SOD, GP, and especially catalase within both target and effector cell may be important determinants of macrophage oxygen-dependent processes.
Release of endogenous C3b inactivator from lymphocytes in response to triggering membrane receptors for beta 1H globulin.
Authors: Lambris J D , Dobson N J , Ross G D
Published: June 2004

Human bone marrow-derived lymphocytes and cells from B lymphoblastoid lines were shown to have specific membrane receptors for beta 1H globin. Lymphocytes responded to the presence of beta 1H by releasing endogenously-synthesized C3b-inactivator. Very little spontaneous release of C3b-inactivator occurred in the absence of beta 1H. beta 1H-treated lymphocytes that either lacked complement receptor type one (CR1, the C4b-C3b receptor) or had their CR1 blocked with Fab'-anti-CR1 formed rosettes with C3b-coated sheep erythrocytes (EC3b) by adherence to complement receptor type two (CR2, the C3d-C3bi receptor). The mechanism of the beta 1H-induced EC3b rosette formation was shown to involve the release of lymphocyte C3b-inactivator that cleaved bound C3b into C3bi forming EC3bi. This lymphocytes-generated EC3bi then bound to CR2, forming rosettes. beta 1H-induced EC3b rosettes were completely inhibited by the presence of either anti-C3b-inactivator, F(ab')2-anti-CR2, Fab-anti-C3c, or Fab-anti-C3d, but were unaffected by the presence of fluid-phase concentrations of beta 1H up to 5.5 mg/ml or Fab'-anti-CR1. Analysis by sodium dodecyl sulfate polyacrylamide gel electrophoresis and fluorography demonstrated that cell-free supernates of beta 1H-treated lymphocytes cleaved 3H-labeled C3b on EC3b into C3bi. Inhibition studies with chelating agents and sodium azide suggested that the release of C3b inactivator might involve a calcium and energy-dependent transport of this enzyme across the membranes of beta 1H-triggered cells. Because plasma beta 1H and C3b-inactivator are known to have important functions in the distinction of alternative pathway-activating substances from normal tissue, it is possible that this beta 1H receptor-C3b-inactivatory releasing system in lymphocytes may have an analogous function.
Demonstration of a soluble mediator that induces exudates rich in Ia-positive macrophages.
Authors: Scher M G , Beller D I , Unanue E R
Published: June 2004

Previous studies have shown that Listeria monocytogenes-immune T cells, adoptively transferred into normal mice with killed Listeria organisms, induced peritoneal exudates rich in Ia-positive macrophages. We show now that culture fluids generated by Listeria-immune exudate cells and Listeria contain an activity that elicits Ia-rich exudates when injected intraperitoneally. The factor that recruits Ia-positive macrophages must be injected several times during a 2-d period for optimal demonstration of its activity. The induction of the factor is immunologically specific and requires Ia-positive macrophages, primed T lymphocytes, and antigen challenge. The factor is a nondialyzable protein and is not genetically restricted in its activity. The macrophages in the exudates induced by the factor bear Fc receptors, take up latex, synthesize I-A, but bear few C3 receptors. We have thus identified an immune mediator capable of controlling the Ia phenotype of the exudate macrophages.
Human autoantibodies that react with both cell nuclei and plasma membranes display specificity for the octamer of histones H2A, H2B, H3, and H4 in high salt.
Authors: Rekvig O P , Hannestad K
Published: June 2004

Sera of some patients with systemic lupus erythematosus and related diseases contain a polyclonal antibody population (cross-reactive antinuclear antibodies [X-ANA]) that react specifically with both core mononucleosomes and plasma membranes of viable nucleated cells. Native mononucleosomes and nucleosome cores assembled from long DNA and the inner histones were indistinguishable in terms of inhibition of binding of X-ANA to nuclei of tissue sections and to polynucleosomes on the walls of plastic tubes. In contrast, mononucleosomes selectively depleted of histones H2A and H2B did not inhibit these reactions. A method was developed for isolation of X-ANA from serum that took advantage of the dual specificity of these antibodies. Immunosedimentation in sucrose density gradients revealed that 125I-labeled Fab' fragments of highly pure X-ANA formed complexes with the inner histones H2A, H2B, H3, and H4 in 2 M NaCL, but not in 0.15 M salt. These results indicate that X-ANA recognize an epitope of the inner histone in 2 M salt, and that in 0.15 M NaCL this epitope is not formed unless the histones interact with DNA to generate a nucleosome structure. Furthermore, in light of the previous demonstration that the epitope is destroyed by trypsin, it may be localized in the N-terminal region of histone H2A or H2B.
Major histocompatibility complex-restricted self recognition. A monoclonal anti-I-Ak reagent blocks helper T cell recognition of self major histocompatibility complex determinants.
Authors: Hodes R J , Hathcock K S , Singer A
Published: June 2004

The functional role of cell surface Ia antigens has been studied for in vitro antibody responses, using as a probe the ability of anti-Ia reagents to inhibit these responses. A hybridoma monoclonal anti-Ia reagent specific for a product of I-Ak (Ia.17) profoundly inhibited in vitro antibody responses to TNP-KLH by spleen cells of the I-Ak but not I-Ab haplotype. This inhibition by anti-I-Ak product, but not by interaction with T or B cell product, in spite of the fact that functional B cells as well as accessory cells could be shown to express the determinant detected by this hybridoma reagent. These results suggest that the Ia expressed by accessory cells in of unique functional importance in these responses. To further characterize the function of Ia antigens in this response system, the mechanism of anti-I-Ak inhibition was determined. The inhibition resulting from interaction of anti-I-Ak with accessory cell Ia was not mediated by nonspecific suppressor cells, nor was there nonspecific interference with accessory cell function as a result of the binding of anti-Ia antibody. The relationship between anti-Ia inhibition and T helper cell recognition of self determinations on accessory cells was analyzed using T cells from radiation bone marrow chimeras. It was demonstrated that (B10 X B10.A)F1 leads to B10 (F1 leads to B10) chimera T cells were able to cooperate with B10 (H-2b and I-Ab) but not B10.A (H-2a and I-Ak) accessory cells for responses to TNP-KLH; F1 leads to B10.A T cells were able to cooperate with B10.A but not B10 accessory cells; and both chimera populations were able to cooperate with (B10 X B10.A)F1 (F1) accessory cells. Monoclonal anti-I-Ak inhibited the cooperation of F1 leads to B10.A T cells with the same F1 accessory cells. Thus, inhibition by anti-I-Ak is dependent upon active helper T cell recognition of I-Ak-encoded determinants expressed on accessory cells. These findings demonstrate that T cells recognize self Ia determinants expressed on accessory cells, and that such recognition is required for the generation of T cell-dependent antibody responses.
Lyb-2 system of mouse B cells. Evidence for a role in the generation of antibody-forming cells
Authors: Yakura H , Shen F-W , Kaemmer M , Boyse EA
Published: June 2004

The Lyb-2 cell-surface alloantigens of the mouse are selectively and perhaps exclusively expressed in the B lymphocyte lineage, but not on antibody- forming cells. Thus if the Lyb-2 molecule is concerned in specific B cell function, it must participate in the generative phase of the antibody response.

Accordingly, monoclonal Lyb-2 antibody was found to depress the plaque- forming cell (PFC) response to sheep erythrocytes in 5-d Mishell-Dutton assays when added within the first 3 d of culture, but not later. The rate of PFC generation was not affected, signifying an absolute reduction in the number of PFC generated. Because reduction of PFC counts by Lyb-2 antibody was not affected by exclusion of Lyt-2(+) T cells, it is unlikely that the reduction depends on augmented suppression by T cells. Augmented B cell- mediated suppression is also unlikely, because the PFC response of serial combinations of congenic Lyb-2.1 and Lyb-2.2 cells, in the presence of monoclonal Lyb-2.1 antibody, was reduced only in direct proportion to the number of Lyb-2.1 cells present. The PFC response of Lyb-2.1/Lyb-2.2 heterozygous cells was not reduced by Lyb-2.1 antibody, presumably because generation of PFC is impeded only if most Lyb-2 sites are blocked. Further evidence that the molecule identified by Lyb-2 plays a critical role in the generation of antibody-forming cells (AFC) in response to T-dependent antigen comes from the finding that Lyb-2 antibody does not reduce the PFC response to the T-independent antigens trinitrophenylated (TNP) Brucella abortus and TNP-FicolI, although elimination of Lyb-2(+) cells from the starting population by Lyb-2 antibody and complement reduces the PFC response to T- dependent and T-independent antigens alike.
Mediation of increased vascular permeability after complement activation. Histamine-independent action of rabbit C5a.
Authors: Williams T J , Jose P J
Published: June 2004

Intradermal injection of zymosan into nonsensitized rabbits induces plasma exudation, which is dependent on two mediators: C5a generated in extravascular tissue fluid and a vasodilator prostaglandin generated from substrates localized in cell membranes. This relationship between the complement system and the prostaglandin synthesis system had not previously been explored, and complement activation has generally been associated with increased vascular permeability via histamine release. We report that C5a increases vascular permeability by a mechanism that is not dependent on histamine release; however plasma exudation is virtually undetectable in the absence of a vasodilator substance. Because the permeability-increasing activity is stable in plasma, analogy with other species suggests that the activity is a result of C5a devoid of its carboxyl terminal arginine (C5a des Arg). This relates the observed permeability-increasing activity with effects on leukocytes rather than effects as an anaphylatoxin.
Precursors of murine B lymphocytes. Physical and functional characterization, and distinctions from myeloid stem cells.
Authors: Paige C J , Kincade P W , Shinefeld L A , Sato V L
Published: June 2004

The emergence of functional B cells was monitored in irradiated or unirradiated CBA/N recipients of either adult bone marrow or fetal liver from CBA/HT6T6 donors. The cells that are primarily responsible for the generation of B lymphocytes, at least during the first 6 wk, are rapidly sedimenting (4.5-6 mm/h), lack surface immunoglobulin, and are found in both the adult bone marrow and the fetal liver from day 12 onward. These pre-B cells are distinct from the colony-forming unit spleen (CFU-s) as demonstrated by the following criteria: (a) absence from yolk sac (19), (b) lack of correlation between CFU-s number and the ability to generate B cells in fetal liver populations of different ages of gestation, and (c) hybridoma antibodies that significantly inhibited B cell reconstitution but have no effect on CFU-s numbers. The antigen detected by this antiserum is present on both the fetal liver and bone marrow B cell progenitor, although its expression is not restricted to the B lineage. The pre-B cells that we monitor are not homogeneous, however, as both physical and functional differences are found. These observations reinforce our thesis that committed progenitor cells for the humoral immune system are formed early in development and thereafter constitute the major precursor pool for the generation of B lymphocytes.
Role of immune recognition in latent allotype induction and clearance. Evidence for an allotypic network.
Authors: Yarmush M L , Sogn J A , Kern P D , Kindt T J
Published: June 2004

The role of allotype recognition in the regulation of the expression of latent allotypes has been investigated in two series of experiments. The first experiments were designed to investigate the apparent instability of latent allotypes in circulation. In these experiments, clearance rates of IgG preparations bearing allotypes matched and unmatched to the recipient were examined. In all cases, iodinated IgG matched in allotype to the recipient was cleared at a normal rate from the serum. However, in several cases, iodinated IgG of an unmatched allotype was cleared at a rate and in a manner suggesting prior sensitization of the recipient to IgG of that allotype. Such apparent sensitization correlated with the presence of the foreign allotypes as a latent allotype in several bleedings taken both before and after the clearance experiment. In the second series of experiments, designed to test the ability of antiallotype antibodies to affect the expression of latent allotypes, five rabbits were immunized first with purified antiallotype antibodies and then after 3-4 mo, with streptococcal vaccine. Examination of the antistreptococcal antibodies for latent allotype revealed, in all cases, that the allotype against which the antiallotype antibodies were directed was present in levels 8- to 20-fold greater than were observed before the antiallotype injections. These results indicate that recognition of allotypic determinants is an important element in the control of latent allotype expression and suggest the existence of a regulatory network involving antiallotype antibodies.
Identification of a human T lymphocyte surface protein associated with the E-rosette receptor.
Authors: Kamoun M , Martin P J , Hansen J A , Brown M A , Siadak A W , Nowinski R C
Published: June 2004

We describe a new monoclonal murine antibody that reacts with a 50,000-mol wt polypeptide that appears to be present on all E-rosetting cells. We conclude that this antigen is either identical to or closely associated with the E receptor because of (a) the high degree of concordance between E-rosette formation and 9.6 antigen expression, (b) the inhibition of rosette formation by preincubation of cells with 9.6 antibody, and (c) the observed failure of cells lysostripped of 9.6 antigen to form E-rosettes. This last finding suggests cocapping of 9.6 antigen and the E receptor.
Genetic resistance to the induction of experimental allergic encephalomyelitis in Lewis rats. I. Genetic analysis of an apparent mutant strain with phenotypic resistance to experimental allergic encephalomyelitis.
Authors: Waxman F J , Perryman L E , Hinrichs D J , Coe J E
Published: June 2004

Clinical resistance to the induction of experimental allergic encephalomyelitis was observed in a closed colony of Lewis (designated Le-R) rats. Disease susceptibility in randomly bred animals appeared to increase with increasing age. In the small group of young Le-R rats, which were susceptible, disease onset was delayed, severity of symptoms was reduced, and duration of clinical signs was abbreviated compared to conventional Lewis rats. The severity of histologic neural tissue lesions correlated with clinical observations. Breeding experiments indicated that most Le-R rats were resistant to disease induction regardless of whether their ancestors had been selected for susceptibility or resistance. The F3 generation of resistant lineage was uniformly resistant at all ages tested. Virtually all (Lewis X Le-R)F1 rats of either sex were resistant when challenged at 7-8 wk of age indicating that resistance was a dominant autosomal trait. Approximately half of (F1 X Lewis) backcross rats developed paralytic EAE whereas one-fourth were entirely resistant, suggesting that disease resistance may be mediated by one or two genes. Le-R rats shared at least some of the Lewis rat major histocompatibility antigens. Resistance apparently did not reflect a nonspecific impairment of cellular immune responsiveness. Le-R rats, which had been challenged with myelin basic protein, developed antigen-reactive cells specific for basic protein or its encephalitogenic fragment. Spleen cells obtained from basic protein-sensitized Le-R rats did not adoptively transfer disease into Lewis rats. In contrast, spleen cells obtained from basic protein-sensitized Lewis rats readily transferred disease into both Lewis and Le-R recipients. These data suggest that disease resistance may be a result of an immunologic deficit (or suppressor cell activity) expressed during the differentiation of antigen-reactive cells into disease-inducing effector cells.
Studies on a new lymphocyte mitogen from Bordetella pertussis. I. Induction of proliferation and polyclonal antibody formation.
Authors: Ho M K , Morse S I , Kong A S
Published: June 2004

Pertussis B mitogen (PBM), isolated from culture supernatant fluids of Bordetella pertussis, is a potent mitogen for mouse and human lymphocytes. In mice, > 95% of the blast cells recovered from PBM cultures bear surface immunoglobulins. Therefore, PBM seems to induce proliferation of mouse B lymphocytes, but not T cells. The proliferative response observed is nonspecific because cells from all mouse strains tested, including germfree animals, are responsive. Moreover, the mitogenic activity of PBM is independent of T lymphocytes, macrophages, or serum factors. When human peripheral blood or cord blood lymphocytes are cultured in the presence of PBM, a high level of thymidine incorporation by these cells is detected. Furthermore, PBM can induce polyclonal antibody formation by both mouse and human lymphocytes. Despite similar methods of isolation, PBM is distinct from the lymphocytosis-promoting factor of B. pertussis, a previously described T cell mitogen.
Potent heme-degrading action of antimony and antimony-containing parasiticidal agents
Authors: Drummond GS , Kappas A
Published: June 2004

The ability of antimony and antimony-containing parasiticidal agents to enhance the rate of heme degradation in liver and kidney was investigated. Trivalent antimony was shown to be an extremely potent inducer of heme oxygenase, the initial and rate-limiting enzyme in heme degradation, in both organs, whereas the pentavalent form was a weak inducer of this enzyme. The ability of antimony to induce heme oxygenase was dose-dependent, independent of the salt used, and not a result of a direct activation of the enzyme in vitro. Concomitant with heme oxygenase induction by antimony, microsomal heme and cytochrome P-450 contents decreased, the cyto-chrome P-450-dependent mixed function oxidase system was impaired, and δ-ami-nolevulinate synthase (ALAS), the rate-limiting enzyme of heme synthesis, underwent the sequential changes-initial inhibition followed by rebound induction-usually associated with the administration of transition elements such as cobalt.

Antimony induction of heme oxygenase however, unlike the enzyme induction elicited by cobalt, was not prevented either by cysteine administered orally or as a cysteine metal complex, or by simultaneous zinc administration. Desferoxamine also did not block heme oxygenase induction by antimony, but this chelator did prevent the rebound increase in ALAS activity associated with antimony or cobalt treatment.

Antimony-containing parasiticidal drugs were also potent inducers of heme oxygenase in liver and kidney. The heme degradative action of these drugs may be related in part to the jaundice commonly associated with the prolonged therapeutic use of these agents.

The heme-oxygenase-inducing action of antimony-containing parasiticidal drugs is a newly defined biological property of these compounds. The relation between the parasiticidal and the heme-oxygenase-inducing actions of such drugs is unknown. However, certain parasites contain hemoproteins or require heme compounds during their life cycle. It may therefore be useful to explore the possibility that the heme-degrading and the parasiticidal actions of certain metals or metal-containing therapeutic agents are in some way related.
Human B lymphocyte subsets. I. IgG-bearing B cell response to pokeweed mitogen.
Authors: Ault K A , Towle M
Published: June 2004

The subset of B lymphocytes having IgG on their surfaces was purified from human spleen and blood using a fluorescence-activated cell sorter (FACS). This subset constituted about 15% of B lymphocytes. The remaining non-IgG-bearing B cells were also obtained for study. These two populations were examined for (a) their expression of other surface immunoglobulin isotypes, (b) their ability to give rise to IgG- and IgM-secreting (plaque-forming) cells in a pokeweed mitogen (PWM)-driven culture system, and (c) their ability to proliferate in response to PWM stimulation. The results of these studies indicate that most IgG-bearing B cells also express surface IgM and IgD. Less than 15% had only IgG. The IgG-positive cell gave rise to both IgG and IgM plaque-forming cells when driven by PWM, and in fact were responsible for most of the total plaque response in both the IgG and IgM classes. The non-IgG-bearing B cells were depleted of both IgG and IgM responsiveness. The failure of the non-IgG-bearing B cells to give a strong response to PWM did not appear to be due to either depletion of accessory cells or to any suppressive influence. Finally, proliferation studies indicated that both the IgG-bearing and the non-IgG-bearing cells proliferated in the presence of PWM with a somewhat stronger proliferative response in the IgG-bearing cells. These results demonstrate that the IgG-bearing cell is not irreversibly committed to IgG production but can also give rise to IgM-secreting cells, and that human PWM-driven immunoglobulin secretory responses are predominantly due to a numerically small subset of B cells.
Interaction of the legionnaires' disease bacterium (legionella pneumophila) with human phagocytes. I. L. pneumophila resists killing by polymorphonuclearleukocytes, antibody, and complement
Authors: Horwitz MA , Silverstein SC
Published: June 2004

We have previously reported that virulent egg yolk-grown Legionella pneumophila, Philadelphia 1 strain, multiplies intracellularly in human blood monocytes. We now report on the interaction between virulent L. pneumophila and human polymorphonuclear leukocytes (PMN), antibody, and complement, in vitro, under antibiotic-free conditions.

L. pneumophila in concentrations ranging from 10(3) to 10(6) colony forming units (CFU)/ml are completely resistant to the bactericidal effects of 0-50 percent fresh normal human serum, even in the presence of high concentrations of rabbit or human anti-L. pneumophila antibody.

L. pneumophila bacteria fix the third component of complement (C3) to their surfaces, as measured by fluorescence microscopy using rhodamine- conjugated goat anti-human C3 IgG, only when the bacteria are incubated with both specific anti-L. pneumophila antibody and complement. Similarly, L. pneumophila adhere to PMN, as measured by fluorescence microscopy, only in the presence of both specific antibody and complement. Electron microscopy revealed that these opsonized bacteria are phagocytosed by the PMN.

PMN require both antibody and complement to kill L. pneumophila; even then, PMN reduced CFU of L. pneumophila by only 0.5 log under conditions in which they reduce CFU of a serum-resistant encapsulated strain of Escherichia coli by 2.5 logs. Separation of PMN-associated and nonassociated CFU of L. pneumophila revealed that the major proportion of the surviving bacteria are PMN associated. Thus, the ineffective killing of opsonized L. pneumophila is a result of a failure of PMN to kill these bacteria after they become PMN- associated. With or without antibody, PMN do not support the growth of L. pneumophila. These findings suggest that PMN, even in conjunction with the humoral immune system, do not play a decisive role in defense against the Legionnaires' disease bacterium.
IgE antibody and resistance to infection. I. Selective suppression of the IgE antibody response in rats diminishes the resistance and the eosinophil response to Trichinella spiralis infection.
Authors: Dessein A J , Parker W L , James S L , David J R
Published: June 2004

Selective suppression of the total IgE antibody response has been achieved in rats by injection of rabbit anti-rat epsilon-chain antibodies. This IgE-specific suppression was maintained during the course of a natural infection by the nematode Trichinella spiralis. Depletion of the IgE antibody response resulted in a marked reduction of the number of eosinophils attracted to the T. spiralis larvae encysted in striated muscle. Blood eosinophilia following T. spiralis infection, although reaching normal peak levels, was abbreviated in IgE-suppressed animals. Moreover, IgE-depleted animals were more susceptible to the infection; they harbored two to three times more larvae encysted in their muscles than their control litter mates.
Antigen-reactive T cells can be activated buy autologous macrophages in the absence of added antigen.
Authors: Hausman P B , Stites D P , Stobo J D
Published: June 2004

T cells responsive to macrophages (M phi) in the autologous mixed lymphocyte reaction (AMLR) contain those cells that can be induced to proliferate by soluble antigens. Negative solution (5-bromo-2-deoxyuridine and light) of T cells activated by autologous M phi also removed those cells required for reactivity to Candida albicans and purified protein derivative. Positive selection of T cells responsive to autologous M phi yields a population that is simultaneously enriched in antigen reactivity. Some patients demonstrating cutaneous anergy and diminished in vitro blast transformation in response to soluble antigen also lack T cells responsive to the AMLR to M phi. When considered in conjunction with previously reported data, these findings indicate the AMLR occurring between T cells and M phi in the absence of soluble antigen represents self recognition occurring between antigen-reactive T cells and antigen-presenting M phi.
Novel structural determinants of the human neutrophil chemotactic activity of leukotriene B.
Authors: Goetzl E J , Pickett W C
Published: June 2004

A specific 5(S),12(R)-dihydroxy-eicosa-6,8,10(trans/trans/cis), 14(cis)-tetraenoic acid, designated leukotriene B, is generated by the lipoxygenation and subsequent enzymatic hydration of arachidonic acid in a variety of leukocytes. Leukotriene B elicits a maximal human neutrophil chemotactic response in vitro which is similar in magnitude to those evoked by the chemotactic fragment of the fifth component of complement, C5a, synthetic formyl-methionyl peptides, and 5-hydroxy-eicosatetraenoic acid (5-HETE). The neutrophil chemotactic potency of purified leukotriene B, assessed by the 50% effective concentration of 6 x 10(-9) M, is equivalent to that of C5a, but is up to 100-fold greater than that of 5-HETE and of other natural di-HETE isomers. 5(S),12(R)-di-hydroxy-eicosa-6,8,10(all-trans),14(cis)-tetraenoic acid, which differs from leukotriene B only in having a trans-double bond in place of a cis-double bond in the triene portion of the molecule, and acetyl-leukotriene B are significantly less potent neutrophil chemotactic factors than leukotriene B, which indicates that both the conjugated double bonds and the free hydroxyl-group(s) are functionally critical determinants. The capacity of acetyl-leukotriene B to inhibit competitively and selectively the human neutrophil chemotactic response to equimolar concentrations of leukotriene B suggests the existence of a specific subset of receptors for this potent lipid mediator.
Cloned cell lines with natural killer activity. Specificity, function, and cell surface markers.
Authors: Dennert G , Yogeeswaran G , Yamagata S
Published: June 2004

Cell lines with natural killer (NK) activity grown from native spleen cells cultured in medium conditioned by spleen cells proliferating in the presence of concanavalin A (Con A) were characterized. One NK cell line was cloned and assayed on several human and mouse NK-sensitive targets to analyze whether target specificities segregate upon cloning. Results showed that NK clones display target specificities identical to NK cells in normal spleen. This suggests that NK cells have no clonally distributed specific receptors to a given target. They may, however, have receptors which recognize identical antigens on all NK-sensitive targets or may possess multiple receptors for different target specificities. NK lines could not be demonstrated to possess activity in antibody-dependent cell-mediated cytotoxicity, nor did they effect mutual lysis. In the presence of Con A, NK cells exhibited dramatically enhanced lysis of NK-sensitive targets but only a slight increase in lysis of NK-insensitive targets. This indicates that the degree of lysis of an NK target is a function of two variables: effector binding to the target and target sensitivity to lysis. Furthermore, it suggests that the affinity of the putative antigen receptors on NK effectors must be rather weak. Cell surface marker analysis reveals that NK cell lines are Thy 1.2+, Lt-1-2-, T200+, asialo GM1+, and asialo GM2+. These markers distinguish NK cells from cytolytic thymus-derived lymphocytes, without resolving the question of classification within a give hematopoietic cell lineage.
Characteristics of human large granular lymphocytes and relationship to natural killer and K cells
Authors: Timonen T , JR Ortaldo , Herberman RB
Published: June 2004

Recent evidence, has demonstrated an association between a subpopulation of peripheral blood mononuclear cells, morphologically identified as large granular lymphocytes (LGL), and natural killer (NK) activity. We have now evaluated more directly the role of LGL in both NK activity and antibody- dependent cellular cytotoxicity (ADCC), by using highly enriched populations of LGL, obtained by centrifugation of peripheral blood mononuclear cells on Percoll discontinuous density gradients. Both spontaneous and interferon- augmented NK and ADCC activities were exclusively associated with the LGL- enriched, low density fractions. The majority of LGL formed conjugates with NK-susceptible and antibody-coated target cells. Approximately 20 percent of small conventional lymphocytes also formed conjugates with the target cells for NK, but this was not associated with cytotoxic activity. Virtually all LGL were found to have receptors for the Fc portion of IgG (FcγR). The frequency of LGL among blood leukocytes was 2-6 percent. LGL could be enriched to an average purity of 95 percent by combining discontinuous density gradient centrifugation with subsequent adsorptions of the low density fractions on monolayers of immobilized immune complexes. About 50 percent of LGL were found to be FcγR-bearing T cells (T(G)), forming low affinity rosettes with sheep erythrocytes at 4 degrees C. Only 10-20 percent of LGL formed high affinity rosettes with sheep erythrocytes at 29 degrees C. LGL could be enriched to a purity of more than 90 percent by depleting high affinity rosette-forming cells from low density Percoll fractions. LGL were only a subpopulation of T(G) cells, because some lymphocytes with conventional morphology also adhered to the immobilized immune complex monolayers and formed high affinity rosettes with sheep erythrocytes. Separation of these cells from LGL by discontinuous density gradient centrifugation indicated that they are not cytotoxic, suggesting a morphological and functional subdivision of T(G) cells. The verification in this study that virtually all human NK and K cells have a characteristic morphology adds a useful parameter to the monitoring of human lymphocytes, and the ability to purify these cells by simple physical procedures should be invaluable in their further characterization.
Trypanosoma cruzi. Surface antigens of blood and culture forms.
Authors: Nogueira N , Chaplan S , Tydings J D , Unkeless J , Cohn Z
Published: June 2004

The surface polypeptides of both cultured and blood forms of Trypanosoma cruzi were iodinated by the glucose oxidase-lactoperoxidase technique. Blood-form trypomastigotes (BFT) isolated form infected mice displayed a major 90,000-Mr component. In contrast, both epimastigotes and trypomastigotes obtained form acellular cultures expressed a smaller 75,000-Mr peptide. Both major surface components were presumably glycoproteins in terms of their binding to concanavalin A-Sepharose 4B. Within a 3-h period, both blood and culture forms synthesized their respective surface glycoproteins (90,000 Mr and 75,000 Mr, respectively in vitro. [35S]methionine-labeled surface peptides were immunoprecipitated with immune sera of both human and murine origin. A panel of sera form patients with chronic Chagas' disease and hyperimmunized mice recognized similar surface peptides. These immunogens were the same components as the major iodinated species. The major BFT surface peptide was readily removed by trypsin treatment of the parasites, although the procedure did not affect the 75,000-Mr peptide from the culture forms. Two-dimensional polyacrylamide gel electrophoresis revealed that the 90,000-Mr peptide found on BFT was an acidic protein of isoelectric point (pI) 5.0, whereas, the 75,000-Mr peptide form culture-form trypomastigotes has a pI of 7.2. The 90,000-Mr component is thought to be responsible for the anti-phagocytic properties of the BFT (1).
In vitro tolerance induction of primed, IgD-negative murine spleen cells.
Authors: Walker S M , Weigle W O
Published: June 2004

The above observations demonstrated induction of immunological tolerance in vitro in primed IgD-, IgG+ B cells. In these studies, addition of trinitrophenylated (TNP) turkey gammaglobulin (TGG) or TNP ovalbumin conjugates suppressed the secondary in vitro response in mice primed with TNP keyhole limpet hemocyanin (TNP-KLH). Suppression was not a reflection of a shift in kinetics of the antibody response, was not dependent on suppressor T cells, and could only be eliciate when conjugate was added within 4 h of addition of TNP-KLH moreover, preincubation of the primed spleen cells with TNP-TGG for 20 h at 37 degrees C, followed by extensive washing, was as effective in inhibiting the response to TNP-KLH as when TNP-TGG was present throughout the 5 d of culture, reflecting induction of a tolerant state. Amounts of conjugate in the concentration range that have been shown by others to tolerize immature or neonatal B cells or mature B cells that have been stripped of surface IgD were sufficient to induce tolerance. The target cells being tolerized did not bear IgD, as determined by B cell depletion and blocking procedures with anti IgD. Whether the lack of surface IgD on the primed cells contributed to the relative ease of tolerance induction was not established by these studies, but the advantages of using primed B cells to examine further the role of surface IgD in tolerance susceptibility was discussed.
Inhibition of glutathione synthesis as a chemotherapeutic strategy for trypanosomiasis.
Authors: Arrick B A , Griffith O W , Cerami A
Published: June 2004

With the expectation that trypanosomal glutathione (GSH) plays a major protective role against the endogenous oxidant stress that results form high intracellular levels of H2O2, we sought to deplete Trypanosoma brucei brucei of their GSH through inhibition of its biosynthesis. Administration of buthionine sulfoximine (BSO), a reversible inhibitor of gamma-glutamylcysteine synthetase, to parasitemic mice resulted in a progressive decrease in trypanosome GSH content, such that parasites isolated after 5 h or BSO treatment contained 50% of normal values. When BSO administration was continued for 18 h (intraperitoneal injection of 4 mmol/kg every 1.5 h), parasitemias temporarily cleared. When inhibitory plasma levels of BSO were maintained for about 27 h, two out of six infected mice were cured and the rest had significantly prolonged survival. These findings demonstrate the potential value of GSH depletion for the treatment of trypanosomiasis.
Neonatal treatment with low doses of anti-idiotypic antibody leads to the expression of a silent clone.
Authors: Hiernaux J , Bona C , Baker P J
Published: June 2004

BALB/c mice immunized with bacterial levan (BL) produce an immune response that fails to generate antibody expressing the idiotype (Id) of the beta (2 leads to 6) fructosan-binding myeloma protein ABPC 48 (A48). Pretreatment of newborn BALB/c mice (at 1 d of age) with 0.01-10 microgram of affinity purified BALB/c anti-A48 Id antibody followed by immunization with BL 1-2 mo later produces an anti-BL response that expresses the A48 Id. This shows that A48 Id+ anti-BL clones belong to a normally silent fraction of the anti-BL repertoire. The activation of A48 Id+ anti-BL clones anti-A48 Id antibody is specific because the pretreatment of newborn mice with anti-MOPC 384 Id antibody, followed by immunization with BL, does not lead to its activation. Moreover, pretreatment of mice with anti-A48 Id antibody does not alter the MOPC 460 Id+ component of the anti-TNP response. It is also important to note that the activation of the A48 Id+ clone in pretreated mice requires subsequent immunization with BL.
Modulation of phagosome-lysosome fusion in mouse macrophages.
Authors: Kielian M C , Cohn Z A
Published: June 2004

A previously described fluorescence assay has been used to characterize factors that modulate phagosome-lysosome (P-L) fusion in mouse macrophages. Fusion was not affected by enzymatic modification or by concanavalin A cross-linking of the plasma membrane or by coating the phagocytic particle with concanavalin A or immune serum. Pretreatment of cells with 10-5-10-4 M colchicine, or treatment immediately after ingestion with 1-10 microgram/ml cytochalasin did not alter P-L fusion; implying that the cytoskeleton does not control fusion in a rate-limiting way. Fusion was strikingly elevated in 5-h cultures of activated macrophages from immune-boosted mice. A lower enhancement was seen in cells activated by proteose-peptone, a nonspecific inflammatory agent.
Chromosomal location of structural genes encoding murine immunoglobulin lambda light chains. Genetics of murine lambda light chains.
Authors: D'Eustachio P , Bothwell A L , Takaro T K , Baltimore D , Ruddle F H
Published: June 2004

To determine the chromosomal localization of murine lambda light (L) chain structural genes, DNA from a panel of 11 mouse x hamster somatic cell hybrids was scored for the presence of sequences homologous to cloned lambda DNA probe molecules. Six of the hybrids had detectable lambda I and lambda II gene sequences. In all six, the full complement of murine sequences was present, and in its germline configuration. The remaining hybrids lacked any detectable murine lambda L chain gene sequences. The only mouse chromosome present in all of the positive hybrids and absent from the negative ones was number 16, allowing the assignment of lambda L chain structural genes to this chromosome. Together with the previous assignments of the kappa L chain genes to chromosome 6 and heavy chain genes to chromosome 12, this finding completes the mapping of Ig structural genes in the mouse at the chromosomal level.