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Biomedical subjects

J W Coleman

Publications and source records attributed to J W Coleman.

At least 19 recordsLinked to original sources
PubMed1992

The cellular and molecular basis for divergent allergic responses to chemicals.

Chemicals vary with respect to the nature of allergic reactions which they will elicit preferentially. A wide variety of environmental and industrial chemicals are known to cause allergic contact dermatitis (contact sensitivity). Some of these are able also to induce respiratory allergy. This article reviews the characteristics of immune responses to different classes of chemical allergens and the role which functional subpopulations of T helper (TH) cells and their soluble cytokine products play in the induction of allergic sensitization. In addition, new opportunities to identify and classify chemical allergens based upon characterization of divergent allergic responses is discussed.

Allergens↗
PubMed1992

Cycloheximide treatment of mouse mast cells inhibits serotonin release. Evidence of a requirement for newly synthesized protein in the exocytotic response.

Treatment of mouse peritoneal mast cells and mouse bone marrow-derived cloned mast cells with the protein synthesis inhibitor cycloheximide led to a marked abrogation of serotonin (5-hydroxytryptamine; 5-HT) release induced by a range of activators including antigen, anti-immunoglobulin E (anti-IgE) antibody, calcium ionophore A23187, and the polycation polylysine. Significant inhibition (28%) of IgE-mediated secretion was attained after incubation of peritoneal cells for only 2 hr, and inhibition progressed over a 24 hr period, reaching greater than 80% after 15 hr. When peritoneal mast cells were exposed to cycloheximide and then washed and returned to culture conditions, a substantial recovery of responsiveness to anti-IgE was seen after 5 hr. Under the same conditions to those used in functional studies, cycloheximide inhibited protein synthesis, measured as incorporation of [35S]-methionine, by purified peritoneal mast cells and cloned mast cells to 18.5% and 7.9% of control levels, respectively. These results show that synthesis of new protein over a period of a few hours is required to render mast cells fully responsive to stimuli that act via the IgE receptor, and to certain other stimuli that are receptor-independent.

Animals↗
PubMed1992

A T-cell response to the anti-arthritic drug penicillamine in the mouse: requirements for generation of the drug-derived antigen.

Mice primed with the anit-arthritic drug D-penicillamine (DP) developed DP-specific T cells in the draining lymph nodes (DLN) which responded to drug-haptenated stimulator cells, but not to untreated control cells nor to free drug, in in vitro proliferation assays. The responder cells were CD4+ and the response was major histocompatibility complex (MHC) class II restricted. The conditions required to generate efficient stimulator cells for in vitro proliferation assays were investigated. Drug-haptenated syngeneic spleen cells, but not thymocytes, were able to stimulate T cells from DP-sensitized mice. However, prolonged incubations of spleen cells with DP were required to generate the drug-derived T-cell antigen. Further experiments revealed that the generation of a DP-derived antigenic determinant for T cells did not require intracellular processing, as stimulator cells pretreated with fixative or lysosomotropic agents before drug haptenation were as effective as untreated DP-haptenated cells in stimulating the responder cells to proliferative in vitro. These findings show that the protein-reactive drug DP can generate a cellular antigen that is capable of stimulating a T-cell response. Furthermore, the generation of this antigen appears to bypass conventional antigen processing, suggesting perhaps a direct chemical modification of cell surface molecules that are involved in immune recognition. This process may underlie adverse reactions to DP that are believed to be mediated by the cellular immune system.

Animals↗
PubMed1991

Interferon-gamma inhibits serotonin release from mouse peritoneal mast cells.

Conditioned medium (CM) from concanavalin A-activated mouse spleen cells inhibits antigen-induced 5-hydroxytryptamine (5-HT) release from mouse peritoneal mast cells when added for 24 or 48 h to cell cultures containing monoclonal IgE sensitizing antibody. We present the following evidence that the spleen cell-derived inhibitory factor is interferon-gamma (IFN-gamma): (a) CM from Con A-activated spleen cells and from Chinese hamster ovary (CHO) cells transfected with the murine (Mu)IFN-gamma gene both produced a graded inhibition of 5-HT release when added to peritoneal cell cultures containing IgE and subsequently challenged with antigen; (b) the relative inhibitory potency of the two preparations corresponded to their relative IFN content as determined by antiviral bioassay; (c) the inhibitory activity of spleen cell CM and of CM from IFN-gamma gene-transfected CHO cells was abolished by treatment with a rat monoclonal MuIFN-gamma-neutralizing antibody, i.e. 5-HT release returned to control levels, and (d) a highly immunopurified preparation of recombinant MuIFN-gamma retained the inhibitory activity, and was active at concentrations as low as 2 U/ml. The inhibitory activity of IFN-gamma appeared to be a direct effect of the cytokine on mast cells, since CM generated for different time periods from unfractionated peritoneal cells treated with purified recombinant MuIFN-gamma contained no inhibitory activity other than IFN-gamma itself, as demonstrated by neutralization of the cytokine with monoclonal antibody. Furthermore, purified recombinant MuIFN-gamma was equally active on mast cells enriched by density centrifugation up to 95% purity as on unfractionated peritoneal cells (1%-2% mast cells). Purified recombinant MuIFN-gamma inhibited 5-HT release induced by a range of different cell activators, namely antigen, anti-IgE, compound 48/80 and calcium ionophore A23187. Hence inhibition is not specific to IgE-dependent activation of mast cells, but seems to be directed more generally at the secretory process of these cells.

Animals↗
PubMed1991

Serum histamine and the elicitation of murine contact sensitivity.

We report that challenge of previously contact-sensitized mice results in a significant increase in the concentration of serum histamine. In an attempt to determine whether this phenomenon might form the basis of an alternative method for the evaluation of elicitation reactions in experimental contact sensitivity, we have compared challenge-induced increases in ear thickness with elevations in serum histamine. Challenge of sensitized mice revealed that both ear thickness changes and increases in the serum level of histamine were dependent upon the concentration of oxazolone used for sensitization. The kinetics of changes in serum histamine concentration were found to be biphasic, with a small increase measurable 2 h following challenge and the maximal response at 24 or 48 h. In contrast, increases in ear thickness were monophasic, although maximum responses were also observed at 24 h. It is concluded that, although they do not exactly parallel increases in ear thickness, changes in histamine concentration may provide a useful serological correlate of the challenge reaction in contact sensitivity.

Animals↗
PubMed1991

Antibodies to tubulin and microtubule-associated proteins. A study in diabetes mellitus, systemic lupus erythematosus, and rheumatoid arthritis.

We report the results of a study of serum antibodies to proteins of the nerve cytoskeleton in patients with Type I and Type II diabetes mellitus, both with and without clinical signs of diabetic neuropathy. In contrast to previous reports, elevated levels of antibody to tubulin or glycated tubulin were not associated with either diabetes or diabetes with related neuropathy. Similarly, clinical evidence of neuropathy in patients with diabetes did not relate to increased levels of antibody to native or glycated microtubule-associated proteins (MAPs). The levels of antibody to MAPs and glycated MAPs were higher in control subjects over the age of 45 years compared with younger control subjects. Increased levels of antibody to tubulin and glycated tubulin were found in the sera of patients with systemic lupus erythematosus, but not rheumatoid arthritis.

Adult↗
PubMed1991

Inhibitors of protein and RNA synthesis block the sensitization of murine peritoneal mast cells.

Addition of the protein synthesis inhibitor cycloheximide (CX, 1 microgram/ml) and the RNA synthesis inhibitor actinomycin D (AD, 0.1 microgram/ml) to unfractionated mouse peritoneal mast cells simultaneously with IgE anti-DNP, for 24 h prior to challenge, completely blocked antigen-induced 5-HT release. Responses to anti-IgE were strongly abrogated whereas responses to the calcium ionophore A23187 were not affected. When CX and AD were added to presensitized cells their effects on antigen and anti-IgE-induced release were much reduced. These results suggest a requirement for protein synthesis during mast cell sensitization.

Animals↗
PubMed1991

Identification of a spleen cell-derived factor that inhibits sensitization of murine peritoneal mast cells as interferon-gamma.

We present evidence that a spleen cell-derived factor that inhibits the sensitization of mouse peritoneal mast cells is IFN gamma. Conditioned medium (CM) from Con A-activated mouse spleen cells and recombinant MuIFN gamma both inhibited antigen-induced 5-HT release from peritoneal mast cells when added at the sensitization stage, but were without effect on presensitized cells. Both preparations were active at dilutions corresponding to similar levels of IFN activity (1-10 units/ml). The inhibitory activity of CM was blocked by a rat monoclonal MuIFN gamma-neutralizing antibody, thus confirming that IFN gamma was the active molecule.

Animals↗
PubMed1991

Penicillamine and penicillin can generate antigenic determinants on rat peritoneal cells in vitro.

Conjugation of the protein-reactive drugs D-penicillamine (PA) and benzylpenicillin (BP) to immune cells to generate drug-derived antigenic determinants has been implicated in drug-induced allergies and autoimmunity. We have therefore developed an in vitro system to demonstrate and characterize the formation of cellular antigens by these drugs. Binding of PA and BP to rat peritoneal exudate cells was detected by a cell ELISA, employing rabbit antisera specific for each drug, and an indicator system employing a second antibody coupled to biotin-streptavidin-beta-galactosidase. For both drugs, binding was detected over the concentration range 125-1000 micrograms/ml. PA bound cells rapidly (maximum binding within 10 min), whereas BP bound relatively slowly (maximum binding occurring later than 4 hr). A possible role for intracellular processing and cellular metabolic activity in the generation of these drug-derived antigenic determinants was examined. Pretreatment of the cells with the fixative paraformaldehyde significantly enhanced binding of PA but not BP. Treatment of cells with the lysosomotropic agents ammonium chloride or chloroquine, or with the metabolic inactivator sodium azide, did not affect the binding of either drug compared with untreated control cells. However, treatment with the oxidising agent copper sulphate, or the cellular activator phorbol myristate acetate, did significantly enhance binding of both drugs to the cells. Therefore, binding of PA and BP to the cell surface appears not to require an intracellular processing event to generate a recognizable antigenic determinant, but is enhanced by treatments that stimulate oxidative processes.

Animals↗
PubMed1990

A comparison of the effects of chlorpromazine and more selective histamine and 5-hydroxytryptamine antagonists on human IgG synthesis in vitro.

We have shown previously that chlorpromazine, a drug associated with immunological abnormalities in vivo, significantly potentiates pokeweed mitogen (PWM)-stimulated IgG synthesis by human peripheral blood mononuclear cells (PBMC) in culture. Chlorpromazine is a pharmacological antagonist of histamine and 5-hydroxytryptamine (5-HT) and thus may exert its immune-enhancing effects by competing with these amines for their respective receptors, which are known to be present on lymphocytes. In this report we show that histamine and 5-HT are present at micromolar concentrations in PBMC cultures. To examine the role of histamine and 5-HT in chlorpromazine-induced enhancement of IgG synthesis we incubated PWM-treated cells with a range of selective histamine and 5-HT antagonists, and with the amines added to cultures either alone or in combination with chlorpromazine. The H1 antagonists mepyramine and promethazine and the H2 antagonist cimetidine had no significant effect on IgG synthesis. The combined 5-HT1/5-HT2 antagonists methysergide and methiothepin also failed to modulate synthesis. Neither histamine nor 5-HT at concentrations up to 100 microM modulated IgG synthesis, nor did they abrogate the enhancement of IgG synthesis induced by chlorpromazine. We conclude that the modulation of IgG synthesis in vitro by chlorpromazine cannot be attributed to an interaction of this drug with lymphocyte receptors for histamine and 5-HT. Other possibilities for the mechanism of action of this drug on immune function are discussed.

Cells, Cultured↗
PubMed1990

The toxicity of amodiaquine and its principal metabolites towards mononuclear leucocytes and granulocyte/monocyte colony forming units.

The cytotoxicity of amodiaquine (AQ), amodiaquine quinoneimine (AQQI) and desethylamodiaquine (AQm) has been assessed in comparison with that of chloroquine (CQ) using mononuclear leucocytes (MNL) and granulocyte/monocyte colony forming units (GM-CFU) from haematologically normal subjects. Toxicity toward MNL was assessed after 2 h and 16 h incubations with each compound. After 2 h, AQ, AQm and AQQI but not CQ (within the concentration range 1-100 mumols l-1) produced a significant decrease in cell viability. After 16 h, all four compounds significantly increased cell death. After both 2 h and 16 h incubations CQ was the least toxic and AQQI the most toxic of the four compounds towards MNL. Toxicity to GM-CFU was assessed by the inhibition of colony formation in vitro. After 10-14 days incubation, there was significant concentration-dependent inhibition of colony formation by AQ, AQm, AQQI and CQ (within the range 0.1-10.0 mumols l-1). There were no significant differences between the ability of the four compounds to inhibit colony formation but toxicity towards GM-CFU was observed at drug concentrations at least 10-fold lower than those that were toxic to MNL. These data show that the four compounds are equally toxic in vitro toward GM-CFU, although some differences in their toxicity toward MNL were seen. The possible mechanisms of AQ's toxicity are discussed.

Amodiaquine↗
PubMed1990

Conditioned medium from concanavalin A-stimulated spleen cells inhibits the IgE-dependent sensitization of murine peritoneal mast cells in vitro.

Conditioned medium (CM) from concanavalin A (Con A)-stimulated murine spleen cells inhibited release of histamine and 5-HT from murine peritoneal mast cells sensitized with monoclonal IgE anti-DNP antibody and challenged with DNP-human serum albumin (HSA) antigen. Inhibition was seen when the CM was added to the mast cells either 24 hr before or simultaneous with, but not 24 hr subsequent to, the IgE, thus showing that inhibition was at the IgE-dependent stage of mast cell sensitization. Unconditioned medium, prepared in the same way as CM but not exposed to spleen cells was without activity, demonstrating that inhibition was due to a spleen cell-derived factor. CM from unstimulated spleen cells was likewise without activity. The sensitization inhibitory factor appears to be a protein, since it was retained upon dialysis, and destroyed by heating at 70 degrees and above. The factor does not appear to be IgE, since it was stable at 56 degrees, and is not IL-1 or IL-2, since recombinant human IL-1 alpha and IL-1 beta, and recombinant mouse IL-1 alpha and IL-2 were without inhibitory activity. The active CM and all recombinant IL-1 and IL-2 preparations did not release histamine or 5-HT directly from mast cells during 48 hr of culture, and did not modulate the histamine content of these cells, nor their capacity to incorporate [3H]5-HT.

Animals↗
PubMed1989

A rat model of captopril immunogenicity.

Following chronic administration of the protein-reactive sulphydryl drug captopril (CP) to rats, an IgG antibody response to CP-derived antigen was detected by ELISA in rats administered the free drug at doses of 270 mumol/kg (i.p. and i.m.) and 27 mumol/kg (i.p.). The antibody response was slow to develop, requiring three series of four daily injections at one-monthly intervals before CP-specific serum IgG was apparent. The IgG antibody recognized CP-ovalbumin but not ovalbumin, and was inhibited by CP in protein-conjugated form, and by free CP and CP-disulphide, thus confirming specificity for a CP-derived antigenic determinant. A drug-induced non-drug-specific IgG response directed against human serum albumin was also observed after chronic high dose CP treatment. No IgG anti-DNA, IgM anti-CP nor IgM anti-HSA responses were seen following chronic drug administration. These studies show that CP, like the model reactive metabolite dinitrofluorobenzene, but unlike other protein-reactive drugs such as D-penicillamine and benzylpenicillin, is immunogenic in the rat. The findings also suggest the possibility that anti-CP antibodies reported in man may be drug-induced, rather than naturally occurring.

Animals↗
PubMed1986

Enzyme-linked immunosorbent assay (ELISA) for detection of antibodies to protein-reactive drugs and metabolites: criteria for identification of antibody activity. Detection and hapten specificity of anti-DNP, anti-captopril and anti-sulphanilamidobenzoic acid.

Certain hypersensitivity reactions to drugs are thought to depend on coupling of reactive species (the drug itself or a metabolite) to macromolecules, leading to the formation of hapten-carrier conjugates. In assays for the detection of antibodies directed against such reactive species the drug or metabolite must be used in conjugated rather than free form. We describe ELISAs for the detection of anti-dinitrophenyl (DNP), anti-captopril (CP) and anti-sulphanilamidobenzoic acid (SABA) antibodies, in which the wells of microtitre plates are coated with hapten conjugated to protein. We define coating conditions and the following 3 criteria for identification of anti-hapten activity: Immunoglobulin in the test sample binds to the immobilised hapten-protein conjugate, but not to the immobilised protein alone. Binding is inhibited by preincubation of the test sample with protein conjugates incorporating the test hapten, but not by preincubation with the same unconjugated proteins, nor protein conjugates incorporating haptenic groups unrelated to the test hapten. The inhibitory hapten-protein conjugates are shown to be inactive in unrelated antigen-antibody interactions. Binding is blocked by preincubation of the test sample with low molecular weight chemical derivatives of the reactive hapten. The inhibitory derivatives must be shown to be inactive in unrelated antigen-antibody interactions. On the basis of these criteria, IgG anti-DNP and IgG anti-CP were detected in the sera of immunized rabbits. The IgG anti-DNP antibody recognised protein-conjugated DNP, DNP-lysine, N-acetyl-DNP-lysine and DNP-S-glutathione, whereas the IgG anti-CP antibody recognised CP-S-S-protein and CP-S-S-CP. By the same criteria IgG anti-SABA was detected in the sera of immunized mice. The antibody recognised free and protein-conjugated SABA, but not free sulphanilamide.

Animals↗
PubMed1985

Inhibition of mast cell sensitization in vitro by a human immunoglobulin epsilon-chain fragment synthesized in Escherichia coli.

An immunoglobulin epsilon-chain fragment was synthesized in E. coli by cloning and expression of the gene coding for the second, third and fourth constant domains of the human IgE heavy chain. The bacterial CH2-4 polypeptide product was assembled by oxidation into a covalently linked dimeric epsilon-chain molecule presumably analogous to the Fc region of native IgE. This bacterial Fc epsilon preparation, within the concentration range 0.01-10 micrograms/ml, inhibited sensitization of human lung mast cells, determined as histamine released upon challenge with specific antigen. Monomer CH2-4 epsilon-chain polypeptide, prepared by reduction and alkylation of the active bacterial Fc epsilon fragment, was inactive as an inhibitor of sensitization. The molar potency of the active bacterial Fc epsilon product was approximately one fourth of that of native IgE. Since the bacterial Fc epsilon is nonglycosylated, carbohydrate does not make an essential contribution to the Fc receptor binding activity of IgE. These results show that a functionally active immunoglobulin molecule can be synthesized by gene cloning and expression in E. coli.

Antibodies, Bacterial↗
PubMed1985

Investigation of the allergenicity of beta-lactoglobulin and its cleavage fragments.

Fragments of beta-lactoglobulin were produced by proteolytic cleavage with trypsin, and chemical cleavage with cyanogen bromide, followed by gel filtration on Sephadex G-50. The antigenicity and allergenicity of the products were studied, before and after reductive cleavage by treatment with 2-mercaptoethanol. The former was determined by inhibition ELISA using IgG anti-beta-lactoglobulin raised in rabbits, whilst the latter was determined by inhibition ELISA and mast cell challenge, using respectively the sera and peritoneal cells of rats experimentally sensitised to beta-lactoglobulin. The findings raise interesting points about the structural basis of allergenicity in relation to antigenicity.

Allergens↗