Bacterial histamine release by immunological and non-immunological lectin-mediated reactions

Prostaglandin D2 Inhibits IgE-Mediated Scratching by Suppressing Histamine Release From Mast Cells

Effects of prostaglandin (PG) D(2), PGE(2), and PGI(2) on itch-associated scratching responses of mice and histamine release from the rat basophilic leukemia cell line RBL-2H3 were examined. PGD(2) and ketotifen but not PGE(2) and PGI(2) suppressed the scratching caused by ovalbumin injected into ovalbumin-sensitized mice. Ketotifen also suppressed compound 48/80-induced scratching but not PGD(2), PGE(2), and PGI(2). In vitro, PGD(2) suppressed the antigen-induced histamine release from RBL-2H3 cells, but PGE(2) and PGI(2) did not. These findings suggest that PGD(2) specifically suppressed IgE-mediated scratching by inhibiting IgE-mediated histamine release from mast cells.

Scratching of their skin by NC/Nga mice leads to development of dermatitis

Effects of scratching behavior on dermatitis, transepidermal water loss (TEWL) and serum IgE concentrations were examined in NC/Nga (NC) mice with toenails (WIT) and without toenails (WOT). The first study was a preventive treatment done to cut off hind toenails before dermatitis induction and the second study was a therapeutic treatment by cutting off hind toenails of NC mice with severe dermatitis. In the preventive study, scratching behavior significantly increased in both WIT and WOT after dermatitis induction. Skin severity score, TEWL, number of mast cells and serum IgE concentration statistically increased in WIT but not in WOT after dermatitis induction. Histological changes coincided with the skin severity score in WIT, while no changes were observed in WOT. In the therapeutic study, skin severity score in WOT but not in WIT statistically decreased after cutting off the hind toenails. TEWL and numbers of mast cells in WOT were statistically lower compared with findings in WIT. Thus scratching up the skin with toenails seemed to be the most important factor leading to dermatitis in NC mice.

Vaginal bacterial flora activates rat peritoneal mast cells

Sixteen strains of physiological and pathological vaginal bacteria were tested for their ability to secrete histamine from rat peritoneal mast cells in vitro. We noticed that Mycoplasma hominis-induced histamine release was very high (up to 53.6%). The stimulation of rat mast cells with Staphylococccus cohnii, Staphylococcus coagulase(-) (two strains), Ureaplasma urealyticum, Peptostreptococcus spp., Bacteroides capillosus, Staphylococcus aureus and Streptococcus agalactiae resulted in lower but significant histamine secretion (11.2%-17.5%). Other bacteria strains (Staphylococcus epidermidids, Enterococcus faecalis, Escherichia coli, Actinomyces naeslundii (two strains) and Lactobacillus fermentum (two strains) caused very low (4.2% - 8.8%) histamine release.

The role of mast cells in host defense and their subversion by bacterial pathogens

Mast cells (MCs) play a prominent role in the early immune response to invading pathogenic bacteria. This newly discovered role for MCs involves the release of chemoattractants that recruit neutrophils and the direct phagocytosis and killing of opsonized bacteria. Whereas these activities are clearly beneficial to the host, certain pathogens have evolved mechanisms to evoke anomalous MC responses to the detriment of the host. These include evoking phagocytosis without killing of unopsonized bacteria and the production of toxins that corrupt the release of mediators by MCs. Elucidating how pathogens subvert the activities of MCs could provide clues to limiting the pathological activities of these cells during infectious diseases.

[The role of infection in asthma]

Since the first decades of the twentieth century, some authors have believed bacterial respiratory infection to be an important triggering factor in bronchial asthma, drawing attention to an asthmatic response to infection. In this context, already in 1995, we presented a study on nasal secretion cultures and the relationship between IgE and sensitization to allergens. There was a statistically significant association between patients with sensitization to Dermatophagoides, elevated IgE levels and Staphylococcus Aureus positive cultures. Following the studies by Norn, we performed a study in 40 children, aged 2-14 years, and observed that these children with sensitization to mites and positive culture released higher histamine levels than did children with negative cultures and controls. The differences were statistically significant. In agreement with other authors, we also found that the presence of both S. aureus and D. pteronyssinus favored antigen specific histamine release. In the last few years, when the increase in the prevalence of bronchial asthma began to be studied, the role of infection, among other factors, in favoring this increase began to be examined. Using the methodology of the ISAAC project, we distributed a parallel questionnaire containing questions on triggering and contributing factors among which was respiratory infection. We found that there was an association between having three of more episodes of bronchitis in the previous year, accompanied by fever and with a duration of more than 7 days and having asthma at some time (OR: 29.09). This association was even higher in patients with wheezing in the previous 12 months (OR: 43.26) and was also associated with the need to present to the emergency department (OR: 30.65). From these results we conclude that respiratory infection is an aggravating factor in asthma, as we already know. For several years, several authors have studied how non-nosocomial respiratory infections can directly modulate Th1/Th2 response. In order to obtain our own results, we studied serum interleukin 4 (IL4) and interferon-gamma (IFN-gamma) in 42 children aged 3-17 years. The most frequent IL-4 values expressed in ng/ml were between 0.25-0.40, with little variation in the sample, which did not permit correlation among variables. Concerning IFN-gamma, we found values between < 5 and 605 pg/ml. In children undergoing antigen-specific immunotherapy, we observed mean IFN-gamma values of 115.86 pg/ml, while children not undergoing immunotherapy and those who had been administered this treatment for less than 1 year, had a mean of 66.06 pg/ml. These differences were statistically significant (p = 0.035), thus revealing a Th1 response to immunotherapy. These differences were not statistically significant when children who had been administered immunotherapy for less than 1 year were included. When we studied children with bacterial immunotherapy and grouped them in the same way, we found that the mean IFN-gamma of the children undergoing immunotherapy for more than 1 year was 56.4 pg/ml compared with 101.75 pg/ml in those without immunotherapy. This difference was statistically significant (p = 0.034). We are able to conclude that bacterial immunotherapy modifies Th1 response, inhibiting it in children with higher susceptibility to infection. In view of these preliminary results, it would be interesting to continue to study interleukins in order to determine the modification of these substances by immunotherapy in a prospective study and with a sample selected in relation to immunotherapy and not other parameters, since those we have studied have shown no relationship.

Microorganism-induced or enhanced mediator release: a possible mechanism in organic dust related diseases

Bacteria were found to trigger mediator release, including histamine, leukotriene B4, and prostaglandin D2. Furthermore, histamine release caused by allergens as well as by nonimmunological reactions was enhanced by bacteria, endotoxins, and spores from molds. Mediator release and its enhancement play a crucial role for bronchoconstriction and inflammatory events in the airways. These effects of allergens, microorganisms, and other noxious agents in dusts may, therefore, in concert be responsible for the symptoms in organic dust related diseases.

Basophil-bound and serum immunoglobulin E directed against Helicobacter pylori in patients with chronic gastritis

The immunoglobulin (Ig) E immune response in patients with Helicobacter pylori-associated chronic gastritis has been evaluated. Of 26 patients with H. pylori infection, 22 (84%) tested positive for basophil-bound specific IgE (determined by the histamine release test) and 18 (69%) for serum specific IgE (determined by an enzyme-linked immunosorbent assay). In contrast, only 1 of 17 persons in whom the bacterium was not detected presented cell-bound and serum specific IgE. In the 4 histamine release test--positive but enzyme-linked immunosorbent assay--negative patients, removal of antibody from the basophil surface by acid elution showed that histamine release occurred through an IgE-dependent mechanism. When normal basophils, passively sensitized with serum from IgE-positive patients, were exposed to the H. pylori antigen, a significant release was observed, confirming the class specificity of the response. Inhibition experiments with bacteria other than H. pylori showed that the IgE antibody was specifically directed against this organism. The percentage of antigen-induced histamine release did not correlate with serum specific IgE level. However, the response of basophils to antigenic challenge was proportional to IgE-dependent cellular releasability. This finding suggests that target cell sensitivity may be the most important factor in determining the entity of biological response to the antigenic challenge. The ability of H. pylori to induce a specific IgE immune response could answer key questions regarding the mechanisms inducing gastric inflammation.

A gap in surface therapy: topical antihistamines

Allergic and non-allergic rhinitis have been treated by many drugs with different modes of action such as topical disodium cromoglycate and ipratropium bromide, systemic antihistamines and corticosteroid drugs and topical corticosteroids. Yet, these therapies are not entirely satisfactory for all symptoms. The rationale for the topical, intranasal use of antihistamines in patients is discussed. Topical antihistamine agents are administered in order to avoid the side effects of systematically applied medications, and to reach higher local drug concentrations. H1 receptors of the nasal mucosa play an important role in the physiopathology of allergic and non-allergic rhinitis and even of infectious rhinitis. Most studies using topical antihistamines in rhinitis, had an experimental physiopathological aim and did not explore clinical efficacy. Recently, topical application of levocabastine--a potent H1 antagonist--yielded good clinical results in allergic conjunctivitis, seasonal allergic rhinoconjunctivitis, and non allergic perennial rhinitis.

Bacterial infection in under school age children with expiratory difficulty

Serological evidence of bacterial infection was prospectively studied in less than 6 years old patients during 188 acute episodes of expiratory difficulty requiring hospital treatment. Such evidence indicated by antibody or antigen assays was found in 40 patients (21%). Streptococcus pneumoniae was identified in 25 cases; antigenemia was found in 10, antigenuria in 2 and seroconversion in 14 cases. Seroconversion to nontypable Haemophilus influenzae was found in 9 and to Branhamella catarrhalis in 2 cases. Seroconversion to Chlamydia spp. was demonstrated in 8 patients, but specific tests for C. trachomatis were negative. C-reactive protein was over 40 mg/L in 35 patients (19%); serological evidence of bacterial infection was present in 14 and absent in 21 of them. Thus, either serological evidence of bacterial infection or an elevated C-reactive protein was found in 61 of the 188 cases (32%). We conclude that bacterial infection is commonly associated with acute wheezing in children under school age. We suggest that bacterial, as well as viral, infections may trigger an acute obstructive attack in children with reactive airways.

Bacteria-induced histamine release from human bronchoalveolar cells and blood leukocytes

Histamine release induced by Staphylococcus aureus was examined in cells obtained by bronchoalveolar lavage (BAL) in non-atopic individuals. Approximately half of the individuals responded with mediator release to the bacterium, and the release was found to be time- and concentration dependent. No difference was found between the patients who responded and those who did not respond in regard to age, sex, smoker/non-smoker, % recovery of BAL-fluid, total cell count, differential cell counts, histamine content per mast cell, or diagnoses. Also stimulation of the BAL-cells with the calcium-ionophore A23187 resulted in histamine release. S. aureus-induced histamine release from basophils was examined in leukocyte suspensions obtained from the same individuals, and in all experiments release was found. The dose-response curves were similar to those obtained with BAL cells. The bacteria-induced mediator release from superficially lying cells in the airways epithelium might be of importance for the precipitation or exacerbation of bronchial asthma in respiratory tract infections.

Influenza A virus potentiates bacteria-induced histamine release. Examination of normal individuals and patients allergic to bacteria

Influenza A virus was found to enhance basophil histamine release induced by Escherichia coli, Salmonella enteritidis, Staphylococcus aureus, Streptococcus pneumoniae and Streptococcus sanguis, but did not per se release histamine. This potentiating effect of the virus was seen both when the bacteria-induced mediator release was IgE-dependent (i.e. patient allergic to bacterium) and when the bacterium caused histamine release by a non-immunological mechanism independent of IgE (putative sugar-lectin mediated). Also histamine release induced by other immunological and non-immunological stimuli, such as anti-IgE, calcium ionophore or agarose beads was enhanced in the presence of the virus. The potentiating effect of the virus on bacteria-induced mediator release might be of importance for the conversion from latent to manifest asthma in upper respiratory tract infections.

Bacteria and endotoxin enhance basophil histamine release and potentiation is abolished by carbohydrates

Histamine release caused by anti-IgE, specific antigens and calcium ionophore A23187 was examined in leukocyte suspensions from healthy individuals and patients allergic to house dust mite and birch pollen. Staphylococcus aureus and LPS from Salmonella typhimurium were found to cause a synergistic enhancement of the release. The potentiation of mediator release by the bacteria and the endotoxin depends on a binding to the basophilocyte, followed by a non-transient event, since the potentiating effect persists after preincubation of the cells with the LPS followed by washout and leaving the cells for 30 min at 37 degrees C before stimulation with anti-IgE. The potentiation was abolished or reduced by galactose (10(-7) and 10(-6) M) and N-acetylglucosamine (10(-6) and 10(-5) M), acting by a binding to the basophil cell membrane, demonstrated by the persistence of effect after preincubation and washout of unbound sugar.

Influenza A virus enhances basophil histamine release and the enhancement is abolished by carbohydrates

Basophil histamine release was studied in leukocyte suspensions from normal individuals and from patients allergic to house dust mite or birch pollen. Mediator release caused by IgE-mediated reactions was examined by stimulating the cells with anti-IgE or specific antigens, and the calcium ionophore A23187 was used for a non-immunological histamine release. In all experiments influenza A virus caused a synergic enhancement of the mediator release and the potentiation was abolished by galactose (10(-7) to 10(-6) M) and by 10(-6) to 10(-5) M of N-acetylglucosamine, alpha-methyl-D-glucoside, alpha-methyl-D-mannoside, N-acetylneuraminic acid and lactose, but not by glucose. Wash-out experiments show that the sugars prevent the aggravation of mediator release by a binding of sugar to the basophil cell membrane, thereby causing a blockade of binding sites responsible for the potentiating effect of virus.

Virus enhances IgE- and non-IgE-dependent histamine release induced by bacteria and other stimulators

Histamine release from human basophil leukocytes was triggered by Staph. aureus, Salmonella enteritidis, non-haemolytic streptococci, or E. coli. Influenza A virus was found to enhance the mediator release and the effect was caused by synergism, since the virus did not induce release of histamine per se. This potentiating effect of the virus was seen both when the bacteria-induced histamine release was IgE-dependent (i.e. patient sensitized to the bacterium) and when the bacterium caused mediator release by a non-immunological mechanism independent of IgE (putative sugar-lectin mediated). Histamine release induced by anti-IgE and calcium ionophore or agarose-beads was also enhanced in the presence of the virus. These findings indicate that influenza A virus potentiates both IgE- and non-IgE-mediated histamine release induced by bacteria and other stimulators.

Influenza A virus enhances Staphylococcus aureus-induced basophil histamine release in normal individuals and patients with intrinsic asthma

Influenza A virus was found to enhance Staphylococcus aureus-induced histamine release in human leukocyte suspensions, but did not per se release histamine. This potentiating effect was found to be similar in cells from normal individuals and from patients with intrinsic asthma. The enhancement of mediator release could be due to viral neuraminidase on the surface of the virus, since a similar potentiating effect was caused by a purified neuraminidase preparation obtained from Vibrio cholerae, and the effect of virus as well as of the purified neuraminidase was completely abolished by a potent neuraminidase inhibitor. The potentiating effect of virus on bacteria-induced mediator release might be of importance for the conversion from latent to manifest asthma in upper respiratory tract infections.

Histamine release from human adenoidal and mesenteric mast cells induced by bacterial antigens

The histamine-releasing capability of Staphylococcus aureus antigens was examined in human adenoidal and mesenteric mast cells obtained by enzymic dispersion of tissues from non-allergic patients. Both populations of mast cells released histamine after challenge with bacterial protein in concentrations between 5-500 micrograms/ml. The release was dependent on the dose, temperature and metabolic energy. The maximum release was observed at 15 min after challenge. The present results suggest that Staphylococcus aureus antigens release histamine from human adenoidal and mesenteric mast cells via a non-cytotoxic, active secretory process.

Non-IgE-dependent bacteria-induced histamine release from human lung and tonsillar mast cells

A wide spectrum of formalin-killed bacteria have been tested for their ability to release histamine from human dispersed lung and tonsillar mast cells. Escherichia coli, Enterobacter cloacae, Staphylococcus epidermidis, Proteus vulgaris, Klebsiella oxytoca and K. pneumoniae were the most effective histamine releasers. Further studies on tonsillar mast cells showed that E. coli-induced histamine release differed from IgE-dependent release with respect to its kinetics, temperature and pH profiles and its sensitivity to calcium deprivation and metabolic inhibitors. A lectin-mediated mechanism may operate, but other non-immunological mechanisms might also be involved in the release. Escherichia coli and anti-IgE did not synergize in inducing histamine release. The production of PGD2 and the failure to detect lactate dehydrogenase following incubation of mast cells with E. coli suggests that histamine release is not due to cytotoxicity.

Bacteria and their products peptidoglycan and teichoic acid potentiate antigen-induced histamine release in allergic patients

Histamine release was examined in leukocyte suspensions from patients allergic to grass pollen, mite or cat dander or to bacteria (antigen). When the cells were challenged with specific antigen plus bacteria to which the person was not sensitized, these bacteria were found to potentiate the allergic histamine release. The potentiating effect by bacteria might be due to the bacterial cell wall components, peptidoglycan and teichoic acid, which mimic the effect of bacteria.

Histamine release induced by bacteria. A new mechanism in asthma?

Bacteria release histamine from human basophil leukocytes and mast cells. The release can be caused by an immunological (IgE-dependent) mechanism, but mostly we found a non-immunological (lectin-mediated) mechanism which indicates that mediator release triggered by bacteria can occur without the person being sensitized to the micro-organism in question. Both bacteria and bacterial products such as endotoxins potentiate basophil histamine release caused by allergens in allergic patients or by bacteria in persons sensitized to the micro-organisms. It is therefore tempting to speculate that bacteria and their products might be of importance for asthma by their capacity to release histamine and to potentiate mediator release.

An IgE response to spirochete antigen in patients with Lyme disease

Most but not all Lyme disease patients produce specific IgE antibodies to Borrelia burgdorferi. Development of IgE antibodies paralleled that of other immunologic classes and appeared to be directed against a polypeptide with a molecular weight of 41,000. Total serum IgE levels in Lyme disease patients were usually within the normal range in all stages of the disease. However, highly elevated total serum IgE in certain patients were not correlated to any particular disease stage nor to specific antibody titers. Spirochetes and spirochetal sonicates in high concentration induced release of histamine from basophils derived from both patients and controls. At lower antigen concentrations, histamine release could be induced only from basophils derived from patients. Synovial fluids from patients with Lyme arthritis contained IgE but only negligible amounts of histamine.

Endotoxins release histamine by complement activation and potentiate bacteria-induced histamine release

The histamine-releasing capability of bacterial lipopolysaccharides (LPS) was examined in human leukocyte suspensions. LPS alone did not release histamine, but it was found to enhance the histamine release caused by bacteria in basophils from persons sensitized to these bacteria. In the presence of serum, LPS was able to release histamine through complement activation. It is speculated that endotoxins reinforce release of histamine caused by bacteria in persons sensitized to these microorganisms, and a direct mediator release via complement activation might play a role in septic conditions.

Influence of bacterial endotoxins on basophil histamine release. Potentiation of antigen- and bacteria-induced histamine release

The histamine-releasing capability of lipopolysaccharides (LPS) was examined in human leukocyte suspensions. LPS alone did not release histamine, but was found to enhance the histamine release caused by anti-IgE. Also the IgE-mediated histamine release caused by specific antigens (allergens or bacteria) in sensitized individuals was enhanced by LPS. The potentiating effect of LPS was observed in grass pollen and dog dander allergic patients as well as in patients sensitized to E. coli or Staph. aureus bacteria. No potentiation was obtained by exposure to unspecific allergens or bacteria to which the persons were not sensitized. Bacteria can release histamine by immunological or nonimmunological mechanisms, and only the immunological histamine release was found to be potentiated by LPS. It is speculated that endotoxins reinforce release of histamine caused by allergens in allergic patients or by bacteria in persons sensitized to these microorganisms.

Bacteria-induced histamine release. Examination of the bacterial cell wall components peptidoglycan, teichoic acid and protein A

The histamine-releasing capability of whole bacteria was examined in leukocyte suspensions from normal individuals. Both gram-positive and gram-negative bacteria caused basophil histamine release. It is probably the bacterial cell wall which interacts with the basophil cell surface leading to release of histamine, since cell walls showed higher histamine releasing capability than the whole bacteria. The releasing effect of the bacterial cell wall components peptidoglycan, teichoic acid and protein A was examined. The peptidoglycan preparations were found to be more potent than the corresponding whole bacteria and cell walls. Since peptidoglycan is found in the cell wall of both gram-positive and gram-negative bacteria, it might be a common factor responsible for histamine release by different bacteria. No release was obtained by teichoic acid, whereas protein A caused histamine release in leukocytes from allergic patients, but only a poor release in normal individuals. The initial step in protein A-induced histamine release might be a binding of protein A to IgE on the cell surface, since removal of cell-bound IgE reduced the release and a high correlation was found between protein A- and anti-IgE-induced histamine release.

Staphylococcus aureus peptidoglycan induces histamine release from basophil human leukocytes in vitro

Whole killed cells, cell walls, and peptidoglycans of Staphylococcus aureus were found to release histamine from human leukocytes and isolated rat mast cells in vitro. The histamine-releasing capability increased in the order of whole bacteria, cell walls, and peptidoglycans. Peptidoglycan was found to release histamine by a nonimmunological mechanism, as demonstrated by release in cells deprived of surface immunoglobulins, whereas whole bacteria and cell walls seemed to operate both by immunological and nonimmunological mechanisms. Histamine release was not a specific property of S. aureus; a wide range of whole bacterial species had this activity. We suggest that peptidoglycan may be a common factor responsible for histamine release by different bacteria.

Complexity of lectin-mediated reactions in bacteria-induced histamine release

We have earlier suggested that bacteria-induced histamine release is caused by different mechanisms, including allergic and non-immunological mechanisms, and that the latter probably depends on lectin-mediated reactions. Two possibilities of lectin-mediated reactions were examined in this study, bacterial surface lectins bind to sugars on the basophil cell membrane leading to histamine release, and the reverse reaction where bacterial aminosugars react with lectins on the basophil cell surface. In the bacterial histamine release caused by the Staph. aureus strain Wood 46 it was possible to demonstrate a reverse reaction, but not a bacterial lectin-mediated reaction. The reaction seems to be complex, as lower concentrations of sugars might potentiate the release of histamine by binding to the target cell or bacteria, while the release is inhibited by higher concentrations.