Mast cells in rat gastrointestinal mucosa. I. Effects of fixation

The effect of compound 48/80 and of electrical field stimulation on mast cells in the isolated mouse stomach

It has been shown that compound 48/80 evokes acid secretion in the isolated mouse stomach by releasing histamine from mast cells. The aim of the present work was to study the distribution and type of mast cells in the isolated mouse stomach and to examine the effect of compound 48/80 and of electrical field stimulation (EFS) on these cells. Histological examination of the stomachs showed only the presence of connective tissue mast cells (CTMC) in all parts of the stomach except in the glandular mucosa where mucosal mast cells (MMC) predominated (MMC -71%, CTMC -29%). Compound 48/80 and EFS did not affect MMC, whereas CTMC showed marked degranulation in all parts of the stomach including the glandular mucosa. It can be concluded that CTMC, present in the gastric mucosa and being sensitive also to EFS, may be involved in the regulation of gastric secretion in the mouse.

Distribution of mast cells in human heart auricles and correlation with tissue histamine

The mast cell density, fixation and staining properties, as well as tissue histamine, were studied in the human heart right auricles of 28 patients with mild atrial or ventricular septal defect (ASD or VSD respectively). We have found that different modes of fixation did not change significantly the mast cell appearance and number as stained with pinacyanol erythrosinate. The mast cell density was 21294 +/- 2775 cells per mm3 tissue and the mean histamine content of the auricle was 900.7 +/- 63.9 ng/g wet tissue weight. A significant positive correlation was observed between mast cell counts and histamine content (r = 0.79, p = 0.001). Furthermore, our data suggest the existence of a non-mast cell pool of cardiac histamine in man.

Studies on the mechanism of ethanol-induced gastric damage in rats

Concentrated ethanol causes gastric lesions by a mechanism that is poorly understood. We have investigated this mechanism in the rat stomach via gross morphologic, videomicroscopic, histochemical, and pharmacologic approaches. Within 1 min of contact, ethanol caused diffuse mucosal hyperemia. By 5 min, hyperemia greatly intensified at some mucosal sites. Beneath sites where mucosal hyperemia developed, intramural venules strongly constricted at 3-13 s postethanol, whereas submucosal arterioles dilated more than two times in diameter by 25 s. Submucosal venular constriction began sooner than arteriolar dilation (9 vs. 16 s, p less than 0.05). One-third of the gastric mucosal mast cells degranulated by 15 s postethanol; 50% discharged by 30 s. Ethanol-induced hyperemia was markedly reduced by lipoxygenase-selective inhibitors BW755C or nordihydroguaiaretic acid, or by the H1-antihistamine pyrilamine, but not by indomethacin, cimetidine, phentolamine, or methysergide. Based on these results, a model for the pathogenesis of ethanol-induced gastric lesions is proposed.

Comparison of human lung and intestinal mast cells

Since much of the data on heterogeneity in the rodent systems are based on differential effects of drugs, we compared responses of human lung mast cell and intestinal mucosal mast cell populations to agents that have revealed mast cell heterogeneity in rat models, as well as to other agents that are effective in both rat peritoneal and intestinal mast cell preparations. Disodium cromoglycate and theophylline inhibit histamine release (HR) from rat peritoneal, but not intestinal, mast cells. We found disodium cromoglycate (10(-4) to 10(-8) mol/L) to be ineffective in both human lung and human intestinal mast cell preparations, whereas theophylline (10(-3) to 10(-6) mol/L) inhibited both lung and intestinal mast cell HR. Quercetin (10(-4) to 10(-8) mol/L) and doxantrazole (3 X 10(-4) to 10(-7) mol/L), which inhibit both rat mast cell types, also inhibit HR in both human mast cell preparations. We also examined the actions of indomethacin and exogenous arachidonic acid and found that neither the lung nor the intestinal mast cells demonstrated the enhancement of HR stimulated by these agents in the basophil. In summary, we have found no pharmacologic differences between the human lung and intestinal mucosal mast cell such as exist in the rodent models. This underscores the limitations of applying the data from animal mast cells to the human mast cells, and at the same time demonstrates that human basophils and mast cells are different.

Formalin sensitivity and differential staining of mast cells in human dermis

The characteristics of the human dermal mast cell population with respect to formalin fixation sensitivity, toluidine blue staining and alcian blue/safranin staining were studied. Thirty-seven specimens of normal human skin were bisected. One half was fixed in 10% neutral buffered formalin and the other in Carnoy's fixative. Sections were cut and stained with either toluidine blue or alcian blue/safranin. Significantly more mast cells were visualized with alcian blue/safranin than with toluidine blue. With both stains, only approximately 50% of the mast cells observed in the Carnoy's fixed tissue could be visualized in the formalin-fixed tissue. Alcian blue/safranin staining revealed three patterns of mast cell granule staining: mast cells containing only alcian blue-positive granules, mast cells containing only safranin-positive granules, and mast cells containing a mixture of alcian blue-positive granules and safranin-positive granules. Mast cells containing only alcian blue-positive granules constituted the majority of the dermal mast cell population and 73% of these mast cells were formalin-sensitive. Mast cells containing only safranin-positive granules and those containing a mixture of alcian blue-positive granules and safranin-positive granules showed no evidence of formalin sensitivity. The human dermal mast cell population, therefore, displays heterogeneity with respect to formalin fixation sensitivity and alcian blue/safranin staining. Dermal mast cells were visualized in significantly greater numbers in skin from the head compared with that from the body or limbs.

Induction of an auto-anti-IgE response in rats. II. Effects on mast cell populations

Immunization of rats with purified rat IgE myeloma (IR2) induces an IgG class autoantibody directed specifically against the IgE isotype. This has variable stimulatory effects on the serum IgE concentration in high IgE-producing BN rats but significantly decreases the serum IgE concentration in the conventional PVG.RT1u strain. We have examined the effects of inducing such an auto-anti-epsilon response on mast cell populations, as defined by their staining characteristics in BN rats. A persistent anti-epsilon response changed the proportions of mast cell types. Those containing highly sulfated, Safranin-positive granules which equate with cells described as connective tissue mast cells (CTMC) were reduced in number in skin, tongue and bone marrow, whereas the less highly sulfated, Alcian Blue-positive mast cells were increased in number in these tissues as well as in the gut, a site rich in the so-called mucosal mast cell. The overall number of mast cells in nonmucosal sites was not significantly changed in anti-IgE-producing rats. The direct effects of anti-epsilon antiserum on mast cells in vivo were investigated using an immediate skin response (ISR) technique. The IgG component of serum from IR2-immunized rats, fractionated by high performance liquid chromatography or eluted from Sepharose 4B-coupled IR2, gave positive ISR in naive rats. The ISR was inhibited by prior incubation of immuno-purified rat anti-IR2 with solid-phase IR2 or with two unrelated IgE myeloma proteins but not with rat IgG. Histological examination confirmed that degranulation of CTMC had occurred at the ISR sites.

Chronic interstitial cystitis: a heterogeneous syndrome

A series of 28 patients with interstitial cystitis and 14 healthy volunteers were studied. We found marked histopathological differences between classic (ulcerative) interstitial cystitis and early (nonulcerative) interstitial cystitis. The bladder mucosa of patients with classic disease exhibited focal ulceration, edema and perineural-perivascular infiltrates. There was a marked increase in 2 distinct mast cell populations. Mast cells increased in the detrusor muscle and mucosa. Mucosal mast cells, unlike those in the muscular coat, are susceptible to aldehyde fixation, and require special fixation and staining techniques for proper demonstration. These cells were numerous in the epithelium and were recovered in bladder washings, consistent with the finding that they have a migratory capacity. In nonulcerative interstitial cystitis all signs of mast cell activation were absent, and the histopathological changes were few and fairly uncharacteristic. We also observed some marked clinical differences between ulcerative and nonulcerative interstitial cystitis. These 2 conditions appear to represent separate entities and should be evaluated separately in clinical studies.

Reconstitution of mucosal mast cells in W/WV mice by adoptive transfer of bone marrow-derived cultured mast cells and its effects on the protective capacity to Strongyloides ratti-infection

Bone marrow-derived cultured mast cells (BMMC) were transferred intravenously into W/WV mice to examine if they could reconstitute defective mucosal mast cell response or defective protective capacity against infection with Strongyloides ratti. When mast cell growth factor-producing activity of W/WV mice were examined, mesenteric lymph node cells obtained at 7 to 14 days after infection could produce this factor in vitro by stimulation with S. ratti-adult worm antigen. A single injection of BMMC (1 X 10(7] on day 7 post-infection (p.i.) neither caused an increase in number of intestinal mucosal mast cells not altered the kinetics of faecal larval output (LPG). On the other hand, serial injections of BMMC (5 X 10(6] from day 5 to 10 p.i. (total 3 X 10(7) cells) resulted in the significant increase in number of intestinal mucosal mast cells. However, this treatment too could not alter the kinetics of LPG. Therefore, adoptive transfer of BMMC could cause the increase in number of histologically detectable-mucosal mast cells, but these cells are, by themselves, not sufficient to cause the expulsion of S. ratti adult worms from the intestine.

Isolated canine mastocytoma cells: propagation and characterization of two cell lines

Five different dog mastocytoma tumors were successfully transplanted and propagated in BALB/c nude mice. Cells from two of these tumors were passaged serially through at least four generations of mice without morphological or functional change. The average yield from a 2-cm tumor harvested from a mouse was 1.2 +/- 2.8 X 10(9) mast cells with greater than 90% viability. Cells of one line were larger and more heavily granulated than the other, and contained 1.29 +/- 0.74 pg histamine/cell (mean +/- SD). Calcium ionophore A23187 and compound 48/80 caused dose dependent histamine release with no significant difference in release from generation to generation. The smaller cells contained 0.06 +/- 0.06 pg histamine/cell. Histamine release after calcium ionophore or compound 48/80 was dose dependent and unchanged through serial passages. Following passive sensitization antigen caused dose-dependent histamine release confirming the presence of IgE receptors on these cells. In both cell lines histamine release was inhibited by terbutaline, dibutyryl adenosine 3',5'-cyclic monophosphate, or isobutylmethylxanthine. These methods provide a morphologically and functionally stable population of nearly pure canine mast cells for biochemical and physiological studies.

Role of inflammation and inflammatory mediators in airways disease

Recent evidence suggests that airway inflammation is linked to hyper-responsiveness of airway smooth muscle. Increases in airway responsiveness after many stimuli are accompanied by increases in inflammatory cells in bronchoalveolar lavage fluid and in the airway epithelium. Airway epithelial cells may themselves be an important source of inflammatory mediators, producing metabolites that can cause chemotaxis of neutrophils and that can selectively activate other cells in the lungs. Mast cells produce a variety of enzymes and vasoactive, chemotactic, and bronchoconstrictor substances in response to non-immunologic as well as immunologic stimuli. The secretory profile of a mast cell may depend upon the specific stimulus applied. In addition, different populations of mast cells exist and distinct enzymatic pathways may predominate in different cell types. Mediators released by these cells may activate target cells by direct or indirect mechanisms. These inflammatory mediators, together with inflammatory cells, are important in the complex interactions involving airway epithelial cells, neutrophils, mast cells, smooth muscle, respiratory secretory cells, and nerves, which, in concert, are responsible for the pathophysiologic manifestations of obstructive lung disease.

Cutaneous mast cell heterogeneity: response to antigen in atopic dogs

Because mast cells (MCs) in skin of atopic dogs are heterogeneous with respect to tissue fixation and staining properties, we determined the effect of antigen on each type of MC in vivo. Skin biopsies were done in anesthetized, ragweed-sensitized dogs before and at 1, 3, 6, and 24 hours after intradermal injections of ragweed antigen (n = 5) or glycerin diluent (n = 4). In each case, one biopsy specimen was fixed with formalin, and a second specimen from an adjacent abdominal site was fixed with basic lead acetate. In sections stained with Alcian blue, 49.7% more MCs (p less than 0.05) were detected in tissue fixed with basic lead acetate ("typical" plus "atypical" MCs: 2916 +/- 581/mm3; mean +/- SEM) than in tissue fixed with formalin ("typical" MCs: 1955 +/- 537/mm3). After antigen, the number of "typical" MCs detectable in tissue sections progressively decreased during the 24-hour period, whereas the number of "atypical" MCs was lowest at 1 hour and had increased at 24 hours. After diluent, MC numbers did not change significantly over time. A late-phase response (LPR), detected clinically as induration and edema, was present 6 hours after antigen in four of five dogs, but LPR was not detected after diluent. The size of LPR was correlated (r = 0.85; p less than 0.05) with the decrease in the number of "typical" MCs at 6 hours. We conclude that the response of the "typical" and "atypical" MC to antigen in vivo differs markedly. The "atypical" MCs participate in the early, acute response to antigen, and the "typical" MCs may be associated with the development of the LPR.

Characterization and functional studies of rheumatoid synovial mast cells. Activation by secretagogues, anti-IgE, and a histamine-releasing lymphokine

Microscopic analysis of synovial specimens from 35 patients with rheumatoid arthritis (RA) and 7 patients with osteoarthritis revealed mast cell hyperplasia in perivascular regions, in fibrous interstitial areas, and clustered around the periphery of lymphoid aggregates. Metachromatic staining, immunofluorescence studies, and ultrastructural analysis revealed a single population of connective tissue-type mast cells with surface IgE receptors. Total extractable histamine of synovial tissue was 4.15 +/- 2.30 micrograms/gm (n = 8) for RA synovium and 0.53 +/- 0.23 microgram/gm (n = 7) for OA synovium. Mast cell secretion was assessed and specific release of histamine from RA synovial mast cells was observed following stimulation with anti-IgE (32.3%), compound 48/80 (40.1%), calcium ionophore A23187 (25.2%), and a partially purified lymphokine with histamine-releasing activity (23.9%).

Two types of human mast cells that have distinct neutral protease compositions

Two human mast cell types were identified by immunohistochemical techniques in skin, lung, and small intestine. One type contains the neutral proteases, tryptase and chymotryptic proteinase, and is termed the TC mast cell. The second type contains only tryptase and is termed the T mast cell. Both types are fixed better by Carnoy's fluid than by formalin. The percentage of mast cells accounted for by the T type was 12 in skin; 98 in mucosa and 13 in submucosa of small intestine; and 77 in bronchial/bronchiolar subepithelium, about 97 in bronchial/bronchiolar epithelium, and 93 in alveoli of lung. Dispersed lung cells contained 90% T mast cells. The mean area of TC mast cells (76 micron2) was slightly larger than that of T mast cells (66 micron2); however, there was such extensive overlap that individual mast cells belonging to different types could not be distinguished on the basis of size. The recognition of human mast cell types with distinct protease compositions suggests a higher level of complexity of human mast cell-mediated reactions than heretofore appreciated.

Effects of somatostatin on ethanol-induced gastric erosions in the rat: role of mast cells

Somatostatin (S) inhibits hemorrhagic gastric erosions produced by ethanol. In this study we compared the dose-dependent effects of linear (reduced) and cyclic (oxidized) S with respect to mast cell degranulation. The gastric mucosal injuries were more inhibited by linear S than by cyclic S. But linear S aggravated injury at a certain dose (10(-7) mol/rat). Mucosal mast cell degranulation correlated significantly with the area of hemorrhagic mucosal lesions (r = 0.91). Both cytoprotection as well as aggravation potency of S may be connected to gastric mucosal mast cell activity in the rat.

Dose-dependent effects of linear and cyclic somatostatin on ethanol-induced gastric erosions: the role of mast cells and increased vascular permeability in the rat

Somatostatin prevents hemorrhagic gastric erosions produced by ethanol. In this paper we describe studies with linear (reduced) and cyclic (oxidized) synthetic somatostatin-14 in the rat model of ethanol-induced gastric mucosal injury. The linear form of somatostatin was more potent at concentrations of 10(-9) to 10(-8) mol per rat than the cyclic isomere. However, at a concentration of 10(-7) mol per rat i.p. injection of linear somatostatin significantly (P less than 0.01) enhanced gastric erosions caused by the alcohol. The area of hemorrhagic mucosal lesions correlated significantly (r = -0.846) with mast cell depletion in the gastric mucosa of the animals. Increased vascular permeability and mast cell degranulation were also observed after intradermal injection of linear or cyclic somatostatin. The 'cytoprotective' as well as the aggravating potency of linear somatostatin may be connected to gastric mucosal mast cell activity in the rat.

The nature and significance of tumour-associated mast cells

The role of the mast cell in tumour growth was examined in the rat with the use of a transplanted sarcoma. Mast cells were found at the periphery of the tumours and in fibrovascular trabeculae within the tumour mass. Histochemical studies showed that these cells contained an immature proteoglycan molecule, in contrast to normal mast cells. The mast cells appeared to be of the connective tissue phenotype and their local occurrence correlated with an anteroposterior difference in tumour growth. Mast cell enhancement of tumour proliferation was demonstrated by the addition of mast cells to the initial tumour inoculum and by pharmacological inhibition of mast cell degranulation.

The isolation and purification of a proteinase with chymotrypsin-like properties from ovine mucosal mast cells

A mast cell granule proteinase was purified from isolated ovine mucosal mast cells by cation exchange chromatography, which defined the conditions for enzyme purification from sheep gastric mucosae. Antibodies raised against the proteinase were used in subsequent purification procedures which yielded 78 micrograms of enzyme per 5 g wet wt of abomasal tissue. Immuno-histochemistry confirmed that mucosal mast cells were the source of the enzyme. The proteinase had chymotrypsin-like esterase activity, with a molecular weight between 19,000 and 25,000.

Effect of N-formylated methionyl-phenylalanine (FMP) and methionyl-leucyl-phenylalanine (FMLP) on gut permeability. A model of local inflammatory process

With the aim of elucidating inflammatory reactions in intestinal mucosa evoked by agents of microbial origin, the effect was assessed on intestinal permeability in the rat of two known chemoattractants for granulocytes and macrophages, N-formyl-methionyl-phenylalanine (FMP) and N-formyl-methionyl-leucyl-phenylalanine (FMLP). Fluoresceinated dextran (mol wt 3000 daltons) was used as a permeability marker. It was found that increasing concentrations of FMP enhanced the transmural passage up to a maximum at 2 X 10(-7)-2 X 10(-6)M. With FMLP the effect was greater than with FMP and measurable at 2 X 10(-9)-2 X 10(-8)M. The increased permeability was apparent 1-5 min after introduction of the peptides and prevailed during the 45-min measuring period. The bimodal response to the peptides is discussed in relation to different potential target-effector cells in the intestinal wall.

Mast cell heterogeneity in dog skin

The degree of metachromasia of mast cell granules is known to vary with the type of tissue fixation and among different tissues and species. The present study sought to determine whether mast cells in dog skin are heterogeneous with respect to fixation and staining properties. We performed skin biopsies in six anesthetized, atopic dogs and one mongrel dog. One biopsy was fixed in formalin and a second, from a parallel abdominal site, was fixed in basic lead acetate (Mota's solution). Adjacent sections from each biopsy were stained with alcian blue (1%, pH 0.5) or for chloroacetate esterase activity. In alcian blue-stained sections, one-third fewer mast cells were detected in skin fixed in formalin (1,836 +/- 454 mast cells/mm3, mean +/- SEM) than in skin fixed in basic lead acetate (2,684 +/- 527 mast cells/mm3) (P less than 0.05). The chloroacetate esterase reaction detected the larger number of mast cells regardless of the fixative used. We conclude that mast cell heterogeneity, as demonstrated by metachromatic staining following different types of tissue fixation, exists in dog skin. "Typical" mast cells stain with alcian blue regardless of fixation; however, "atypical" mast cells exhibit metachromasia only after fixation in basic lead acetate. Both the typical and atypical types of mast cells have chloroacetate esterase activity.

Bronchoalveolar mast cells in extrinsic asthma: a mechanism for the initiation of antigen specific bronchoconstriction

Bronchoalveolar lavage performed in 10 patients with extrinsic asthma and 14 controls yielded similar recoveries of fluid and cells. Mast cells and eosinophils, however, formed a greater proportion of the cells recovered from the asthmatic subjects (p less than 0.001 for mast cells; p less than 0.01 for eosinophils), the histamine content of the lavage cells being correspondingly increased (p less than 0.01). Both the percentage of mast cells and the histamine content of lavage cells were significantly inversely correlated with the forced expiratory volume in one second (FEV1; expressed as percentage of predicted) and with the ratio of FEV1 to forced vital capacity before lavage. There was also a significant inverse correlation between the concentration of histamine required to produce a 20% fall in FEV1 and the percentage of mast cells recovered (p less than 0.05). When incubated with antihuman IgE bronchoalveolar mast cells from asthmatic subjects released a significantly increased proportion of total cellular histamine than cells from control subjects at all effective doses of anti-IgE. By contrast, dose response curves for IgE dependent histamine release from peripheral blood leucocytes were similar in asthmatics and controls. Specific antigen led to release of histamine from bronchoalveolar cells and peripheral blood leucocytes of asthmatic subjects but not controls. Lying superficially within the airways, bronchoalveolar mast cells would be readily exposed to inhaled antigen and would release mediators directly on to the airway surface. Their immunological response suggests that they are likely to be important in the pathogenesis of airflow obstruction in asthma.

Multiple sites of histamine storage in superior cervical ganglia

Histamine and mast cells are present in substantial quantities in superior cervical ganglia (SCG) in a variety of animals. In this study, SCG from mast cell-deficient W/Wv mice, from cogenic +/+ wild-type, and from Wistar control mice were examined for their endogenous histamine content and mast cell numbers. Measurements of SCG extracts with a micro-radioenzymatic histamine assay revealed that +/+ and Wistar ganglia contained about 20 pmol histamine per ganglion or 0.6 nmol/mg protein. Light microscopic inspection with toluidine blue staining of 6-micron sections prepared from +/+ and from Wistar SCG showed the presence of about 85 mast cells in each species. By contrast, no mast cell was observed in serial-sectioned SCG from W/Wv mice; despite the absence of stainable mast cells, their SCG consistently contained endogenous histamine, on average, 2 pmol per ganglion. These results are interpreted as evidence for the existence of a nonmast cell histamine compartment in sympathetic ganglia.

Heterogeneity of mammalian mast cells differentiated in vivo and in vitro

The evidence for mast cell heterogeneity in vivo has grown in the last several years from the initial morphologic and histochemical observations to biochemical and functional criteria. In several species, there appear to be at least two distinct classes of tissue mast cells that differ in their content of intragranular amines, proteoglycans, and proteases and in their metabolism of arachidonic acid after cell activation. With the recent discovery of differentiation/growth factors for mast cells in vitro, it has been shown that a discrete subpopulation of cells resembling one of the two in vivo classes can be derived in culture. The diversity of mast cell mediators synthesized by these various populations and their potential functions in vivo imply that mast cells may be involved not only in allergic responses but also in other inflammatory processes, including tissue repair and growth.

Density of mucosal mast cells in the lamina propria of the colon and terminal ileum of children

Ileal and colonic biopsies from children observed to be histologically normal were fixed in Carnoy's fluid, sectioned, and stained by the chloroacetate esterase reaction. The density of mucosal mast cells was higher in the terminal ileum than the colon, but did not vary significantly within the colon.

Two biochemically distinct populations of histaminocytes separated by isokinetic sedimentation of dispersed rat gastric cells

Two populations of histaminocytes, with different sedimentation rates (SR), were separated by a computer developed isokinetic gradient using dispersed rat gastric mucosal cells. Histamine content, histidine decarboxylase (HDC) activity and incorporation of radiolabelled histidine metabolites were used to assess the migration of specific cells throughout the gradients. One histaminocyte population, with cells of lower SR, contained high HDC activity and undetectable levels of histamine, whereas the other population, with cells of higher SR, contained lower HDC activity and high concentration of histamine. Both types of histaminocytes incorporated 3H-histidine metabolites. Electron microscopy showed that the fractions containing histaminocytes with lower SR had 3.5 times more endocrine ECL cells than the original population of dispersed fundic cells and lacked A and D cells, whereas the fractions with histaminocytes of higher SR were associated with a 2.7 times higher concentration of A and D cells and with a 7.7 times higher ratio of a variety of partial cells with a distinct mitochondrial morphology. These results are consistent with prior novel information regarding the separation of two populations of rat histaminocytes using different sedimentation techniques.

The effect of nedocromil sodium and sodium cromoglycate on antigen-induced bronchoconstriction in the Ascaris-sensitive monkey

Nedocromil sodium inhibited the bronchoconstriction caused by antigen challenge in Ascaris-sensitive monkeys and in addition it prevented the release of histamine from mast cells lavaged from sensitive monkeys. Sodium cromoglycate was relatively inactive in both these systems. It is suggested that nedocromil sodium can stabilize both mucosal and connective tissue mast cells and may represent a new type of drug.

Glycosaminoglycans in rat mucosal mast cells

Rats were infected with the nematode Nippostrongylus brasiliensis, resulting in an approx. 5-fold increase in the number of mucosal mast cells and the histamine content of the intestinal (jejunum) wall. After injection of the infected animals with inorganic [35S]sulphate, a similar increase in the yield of labelled intestinal glycosaminoglycans was observed, compared with uninfected control rats. Autoradiography showed a highly selective labelling of the numerous mucosal mast cells and of the few connective-tissue mast cells in the subserosal region of the bowel. Analysis of the labelled polysaccharide from the infected animals showed that almost 60% of this material consisted of oversulphated galactosaminoglycan, whereas heparin-related polysaccharides accounted for only 13%. The galactosaminoglycan contained 4-monosulphated and 4,6-disulphated N-acetylgalactosamine residues in approx. 5:1 molar ratio, both being linked to D-glucuronic acid residues; the occurrence of L-iduronic acid units could not be excluded. No significant difference in structure was found between this polysaccharide and the corresponding component isolated from uninfected rats. It is concluded that the major polysaccharide produced by rat mucosal mast cells in vivo is an oversulphated galactosaminoglycan rather than heparin.

Cellular repository for blood histamine in normal and nematode-infected rats

Infections with the nematode N. brasiliensis is associated with a recruitment of intestinal mucosal mast cells (MMC) which increase greatly in numbers. We have studied histamine levels in the gut, whole blood and plasma in relation to MMC of the gut and blood cell morphology during the course of the infection in an attempt to clarify possible relations between circulating blood basophils and MMC. The results show a parallel increase in MMC numbers and histamine content of the gut, remaining high to day 20 after infection. Blood histamine increased from a control level of 30-40 ng/ml to a maximum of 200 ng/ml on day 12 to 14, but returned towards the control level already on day 16 after infection. There was a corresponding increase in plasma histamine to a maximum of 80 ng/ml. The total number of blood neutrophils increased during the early phase of the infection and there was a pronounced eosinophilia from day 10 to 16. No cells containing metachromatic granules were found in a screening comprised of 10,000 cells per specimen. During day 10 to 16 we found a number of coarsely granuled and vacuolated cells. The granules stained darkly by the Giemsa stain but not metachromatically with Toluidine Blue or with Alcian Blue at a low pH. We interpret this as an equivalent to the so-called toxic granulation occurring in human neutrophils. These cells may have been mistaken for basophils by previous investigators. The cellular repository for the high concentration of histamine in the blood is unknown. We suggest, as a working hypothesis, that it is contained in a circulating progenitor for MMC which has the ability to synthesize and, in a loosely bound state store, histamine, but which has not yet acquired the ability to assemble the specific metachromatic granules.

Histochemical demonstration of chymotrypsin like serine esterases in mucosal mast cells in four species including man

Serine esterases were detected in the granules of mucosal mast cells from rat, mouse, sheep, and man. Successful demonstration of enzyme activity required brief fixation (6 h) of tissues in 4% paraformaldehyde. Staining with naphthol AS-D chloroacetate produced an intense red reaction product in intraepithelial mucosal mast cells (globule leucocytes) and mucosal mast cells within the lamina propria of the gastrointestinal tract. The mast cell identity of cells stained for esterase was confirmed by sequential staining with toluidine blue (pH 0.5). Furthermore, the numbers of cells detected after staining for esterases or with toluidine blue were highly correlated. Esterase activity within mucosal mast cells/globule leucocytes from all species was inhibited with the serine enzyme inhibitor phenylmethylsulphonyl fluoride. Further histochemical studies with the substrate, N-acetyl-DL-phenylalanine B-naphthyl ester, indicated that mucosal mast cells and globule leucocytes contain esterases which are chymotrypsin like in substrate specificity.

Mast cell depletion in murine chronic graft-versus-host disease

A murine model of chronic graft-versus-host disease (GVHD) was induced across minor histocompatibility barriers. This was done by injecting B10.D2 (H-2d) spleen cells into irradiated BALB/c (H-2d) mice. Chronic GVHD in this model includes features common to human idiopathic scleroderma, such as dermal fibrosis, loss of dermal fat and appendages, and a mononuclear cell filtrate. Serial skin biopsies showed a progressive loss of stainable mast cells in GVHD but not in irradiated controls. Mast cell depletion was noted as well in the tongue and kidney capsule of GVHD mice. Mast cell depletion was noted as early as 11 days after GVHD induction and persisted for at least 56 days. A hypothesis is put forth linking the T-cell activation of GVHD, mast cell degranulation, and increased fibrosis. The pertinence of this hypothesis to idiopathic scleroderma is pointed out.

Mast cells in rat thalamus: nuclear localization, sex difference and left-right asymmetry

Mast cells were positively identified in rat brain by a combination of staining and histochemical procedures. These cells stained positively with toluidine blue and Astrablau at low pH, indicating the presence of a proteoglycan similar to that found in peripheral mast cells. Brain mast cells also fluoresced after o-phthalaldehyde exposure, indicating that they contain histamine. Mast cells varied greatly in number among brains, but their distribution was almost exclusively thalamic; within thalamus, the ventral complex, medial dorsal, lateral, and paraventricular nuclei contained the most mast cells. Mast cell numbers were greater in brains of females than of males, and greater in left than in right hemispheres. These findings suggest that mast cells have a specialized function in thalamus and/or that the vascular environment of the thalamus is particularly conducive to mast cell accumulation.

A method for the preparation of imprints from the nasal mucosa

Important immunological reactions take place on the surface of mucosal membranes. Improved methods for the sampling and quantitative study of the cells taking part in these reactions are therefore desirable. We here describe a new technique for the preparation of imprints from the nasal mucosa. The method utilizes a plastic film coated with a thin layer of an albumin-glycerol mixture to improve cell adherence to the surface. The membrane is gently pressed onto a defined portion of the mucous membrane. Fixation and staining procedures are performed on the plastic film, which is then mounted on a slide and covered by a coverslip. The preparations have excellent optical properties and specific cell types can be easily studied, quantified and related to the specific area of the mucosa from which the imprint was taken.

Mast cell heterogeneity: evidence and implications

Mast cells and basophils play a fundamental role in the pathogenesis of allergic disease, although their physiologic role is largely unknown. A large body of evidence now indicates that the properties of mast cells are dependent on the tissue and species from which they are derived. Such mast cell heterogeneity encompasses differences in morphology, development, cytochemistry, and function. The evidence for such heterogeneity, and some of its clinical implications, is discussed.

Gut mucosal mast cells. Origin, traffic, and differentiation

Gut mucosal mast cells (MMC), which are nearly absent in normal mice are abundant during nematode infection. In normal mice, study of MMC precursors (MMC-P: cells giving rise to MMC colonies in the presence of IL-3) show that: (a) their frequency, judged by limiting dilution is very high in bone marrow (BM) and gut, and very low in most lymphoid organs and thoracic duct lymph (TDL); (b) gut MMC-P are Thy-1- Lyt-1-2- and are not rapidly replicating; (c) they are the progeny of less differentiated BM MMC-P which are attracted from the blood to the gut mucosa by local factor(s), other than antigen and T cell factors (since normal amounts of gut MMC-P are found in germ-free, nude, and newborn mice). In mice bearing the Wehi 3 tumor (which releases enough IL-3 to produce detectable blood levels) spleen and mesenteric lymph nodes (LN) show increased MMC-P frequency, the greatest increase being in the gut and BM, where numerous differentiated MMC are found. In Nippostrongylus brasiliensis (Nb)-infested mice (known to develop a large, T cell-dependent, gut MMC infiltration), gut MMC-P proliferation is induced by IL-3 released from gut mucosal Thy-1+ Lyt-2- cells, whose in vitro IL-3 release capability is much higher than that of similar cells from normal mice. Both Nb-stimulated T blasts and proliferating MMC-P undergo cyclic traffic, migrating into the TDL and then seeding the whole length of the gut (a process which allows a widespread immune defense after a local antigenic stimulus). Experiments using 2-d interruption of this traffic and fetal gut grafts, suggest that the continuous homing of T blasts back to the gut which leads to permanent Nb-stimulated IL-3 release, is essential for the full maturation of MMC. Transfer experiments in the rat show that TDL circulating MMC-P rapidly mature into MMC when they home back to the Nb-infested gut. It is proposed that gut MMC arise after several stages of progressive differentiation of MMC-P, influenced both by IL-3 and unidentified gut factor(s).

Turnover of histamine in mucosal and connective tissue mast cells of the rat

Mast cells constitute a heterogenous cell system. The specific type of mucosal mast cell (MMC) of the gut differs with respect to a number of properties from the classical connective tissue mast cell ( CTMC ) found in, e.g. skin, tongue and the peritoneal cavity. This report summarizes recent findings concerning turnover rates of amines and heparin in the two cell types. The elimination rate of radioactively prelabelled histamine, 5-hydroxytryptamine (5-HT) and heparin from peritoneal CTMC was compared with the elimination of radiolabelled histamine from tongue, where histamine is stored in CTMC and duodenum where it is stored in MMC. The elimination of histamine from peritoneal CTMC was slow (t 1/2 = 23 days) and did not differ significantly from that of 5-HT (t 1/2 = 25 days) and heparin (t 1/2 = 35 days) suggesting a low degree of secretory activity in the normal rat. The elimination rate of histamine from the tongue was also very slow. The specific radioactivity of histamine in duodenum was decreasing more rapidly. This was explained by a dilution of the radioactivity since the histamine content increased during the experimental period, and also by MMC death. The results are compatible with the assumption that CTMC and MMC are secretory cells, but with low activity until recruited by adequate, immunological or other stimuli.

Separation and characteristics of two histaminocytes from rat gastric mucosa

To determine the properties of rat gastric cells involved in histamine metabolism (histaminocytes), fundic mucosa was enzymatically dispersed prior to separation by sedimentation methods. The distribution of histamine content, histidine decarboxylase (HDC) activity and incorporation of radioactive histidine metabolites were used to determine the characteristics of various populations of gastric cells. All activities measured, as well as most of the dispersed gastric cells, occurred in a narrow range of density between 1.083 and 1.091 g/ml. Velocity sedimentation showed that two populations of histaminocytes can be distinguished. One population has a higher sedimentation rate, suggesting a larger size, contains histamine, HDC activity and incorporates radioactive metabolites. Another population, in fractions with lower sedimentation rates, contains little histamine, has a higher HDC activity than the previous population and also incorporates radiolabelled histidine metabolites. For the first time, two populations of viable histaminocytes have been separated that differ in their biochemical properties.

Concomitant detection of mucosal mast cells and eosinophils in the intestines of normal and Nippostrongylus-immune rats. A re-evaluation of histochemical and immunocytochemical techniques

The granules of mucosal mast cells (MMC) in the rat and man are apparently poorly fixed with formaldehyde and special fixation techniques are normally used to demonstrate MMC glycosaminoglycans (GAG) in these two species. However such techniques do not permit the study of MMC granule enzyme cytochemistry or the demonstration of eosinophils. We have, therefore, examined some histochemical and immunocytochemical properties of MMC and eosinophils in normal and parasitised rats following various fixation procedures. Immersion fixation of rat intestine in 4% paraformaldehyde for 6 h not only facilitated the demonstration of MMC glycosaminoglycans with basic dyes but also permitted the concomitant staining of eosinophils with acidophilic dyes. A MMC granule-associated serine esterase was also demonstrated by enzyme cytochemistry and rat mast cell protease II was detected within MMC granules by immunocytochemistry. This new methodology obviates the requirement for separate fixation procedures in the identification and characterisation of MMC/eosinophil interactions in normal and parasitised rat intestinal mucosa.

Spontaneous autoradiographic grain activation associated with mast cells in methacrylate plastic embedded tissue sections

Autoradiographic tracing using tritium labeled compounds or cells is a common laboratory technique for light and electron microscopy. This report describes a chemographic effect associated with certain cells in sections from tissues embedded in the new methacrylate plastic embedding compounds. When tissue sections from rats and rhesus monkeys that received no radioisotope were coated with nuclear track emulsion and subsequently developed, cells with morphologic characteristics of mast cells showed significant grain formation over the entire cell. Three different types of methacrylate plastics were tested using rat and monkey tissues and all three were found to promote grain formation over mast cells; however, this phenomenon was not seen in similar tissue sections from paraffin or epoxy embedded material. The properties of methacrylate plastics which promote positive chemography by mast cells may reflect the greater permeability of this class of plastics. Due to their wide tissue distribution, the presence of such chemographically active cells could cause false estimates of the distribution of either exogenous radiolabeled cells or radioisotopes within many tissues.

Typical and atypical mast cells of the rat gastrointestinal system: distribution and correlation with tissue histamine

Mast cells and histamine are present throughout the rat gastrointestinal system. Typical mast cells, differentiated from atypical mast cells by morphology, staining characteristics, and response to Compound 48/80, were the only mast cell type identified by histology in the cheek, tongue, esophagus, and nonglandular stomach. Atypical mast cells were found in large numbers in the glandular stomach, small and large intestine, and cecum, where they outnumbered typical mast cells by up to 20:1. Gastrointestinal histamine levels varied from 2.6 to 19.3 ng/mg in all tissues surveyed except for the glandular stomach, which contained 26 ng/mg. The amount of histamine per typical mast cell was estimated to be approximately 1.29 picograms; atypical mast cells contained less than 0.15 picograms per cell. Parenteral administration of Compound 48/80 resulted in the degranulation of typical mast cells, but not atypical mast cells, as determined by a fall both in typical mast cell number and a decrease in tissue histamine in areas rich in typical mast cells. These results indicate that striking regional differences in mast cell distribution and tissue histamine levels exist in the rat gastrointestinal system.

Two classes of mouse mast cells delineated by monoclonal antibodies

A panel of rat monoclonal antibodies was used to classify mouse mast cells from four different sources on the basis of their surface determinants. Three populations of mast cells were derived by culturing normal bone marrow, spleen, and peripheral blood cells, whereas the fourth population was isolated directly from the peritoneal cavity. For each population, a surface antigen phenotype was determined by indirect immunofluorescence microscopy and compared to the phenotypes of the other populations of mast cells. The results showed that culture-derived mast cells, regardless of origin, had nearly identical antigen phenotypes, suggesting that these populations were comparable. By contrast, peritoneal mast cells had a different phenotype, suggesting that they represented a class distinct from culture-derived mast cells. These findings, which corroborate classification schemes based on nonimmunologic methods, demonstrate that subpopulations of mouse mast cells can be distinguished antigenically.

Factor-dependent in vitro growth of human normal bone marrow-derived basophil-like cells

A factor(s) present in supernatants from lectin-stimulated peripheral blood mononuclear cells promoted the production of basophil-like cells in liquid cultures of normal human bone marrow cells. The cultured basophil-like cells had lobulated or round nuclei, and the cytoplasmic granules stained metachromatically with toluidine blue and azurophilic with Giemsa. 20% of the metachromatically staining cells were peroxidase positive but not positive for nonspecific esterase. The histamine content was 0.5-2 pg/cell. The basophil-like cells released histamine upon challenge with calcium ionophore A23187 but not with compound 48/80. They also released histamine with anti-IgE when passively sensitized with human myeloma IgE. The development of basophil-like cells was promoted in a dose-dependent fashion by a factor(s) in the conditioned medium. Blocking of cell proliferation with hydroxyurea or X irradiation inhibited the development of basophil-like cells. The production of the factor was dependent on the presence of T cells. The factor was different from interleukin 2 and its molecular weight was estimated to be 25,000-40,000 by gel filtration on a Sephacryl S-200 column. Thus, human basophil-like cells derived from normal bone marrow cells can grow and differentiate in vitro under the regulation of T cells.

Mucosal mast cells of the rat intestine: a re-evaluation of fixation and staining properties, with special reference to protein blocking and solubility of the granular glycosaminoglycan

Mucosal mast cells of the gastrointestinal tract constitute a separate cell line within the mast cell system of the rat, differing in several respects from the classical connective tissue mast cells and, unlike the latter, requiring special fixation techniques for their demonstration. We have examined some histochemical properties of mucosal mast cells of the duodenum and compared them with connective tissue mast cells of the tongue or skin. The results indicate that the structural integrity of the granules of both types of mast cell is partly dependent on ionic linkages between glycosaminoglycan and protein. The so far unidentified glycosaminoglycan of mucosal mast cells appears to be more soluble than the heparin of connective tissue mast cells. The strongly fluorescent binding of Berberine to the granules of connective tissue mast cells and, depending on their content, of heparin is absent from mucosal mast cells, confirming previous findings which suggested that they contain a glycosaminoglycan with a lower degree of sulphation. Aldehyde fixation by routine procedures reversibly blocks the cationic dye binding of mucosal mast cell granules. The dye binding groups may be unmasked by trypsination or by long staining times of the order of several days. The results suggest that the blocking of staining by aldehydes is caused by a diffusion barrier of a protein nature. Mucosal and connective tissue mast cells thus differ with respect to the spatial arrangement of glycosaminoglycan and protein in their granules. As a result of the study a modified method for the demonstration of mucosal mast cells in tissue sections is described, based on normal formaldehyde fixation and staining in Toluidine Blue for a long time. It has some advantages over previous methods and preserves the structure of mucosal and connective tissue mast cells equally well.

Mast cells in the submandibular gland of cat

The effects of pilocarpine, compound 48/80 and the electrical stimulation of the chorda tympani nerve on the morphology of the mast cells from the submandibular gland of the cat were studied. All those different treatments of the gland caused the enlargement of the tissue mast cells. We observed also in the glands treated with pilocarpine and compound 48/80 a degranulation of mast cells. The degranulation was more expressed after the application of compound 48/80 to the animals.