Mast cells contribute to PACAP-induced dermal oedema in mice.

In the present study the effect of intradermal PACAP-injection on dermal oedema in mice was investigated and the contribution of mast cells to this response was assessed. The injection of PACAP 1-38 into the ears of C57BL/6 mice evoked a dose-dependent response, which, after higher doses of PACAP 1-38, lasted at least 24 h. Histological examination showed significant mast cell degranulation induced by PACAP. Using mast cell-deficient WBB6F1-Kit(W)/Kit(W-v) mice and the congenic mice, we demonstrated that the the early phase (30 min to 6 h) of PACAP-induced ear swelling response was significantly diminished in mast cell-deficient mice, suggesting that mast cell degranulation contributes to this phase of the response. When mast cell-deficient WBB6F1-Kit(W)/Kit(W-v) mice were locally and selectively reconstituted by adoptive mast cell transfer, the dermal oedema was almost equal to that of control animals in the early phase of PACAP injection. These results show that mast cell degranulation contributes to PACAP-induced dermal oedema in mice.     

Substance P induces granulocyte infiltration through degranulation of mast cells

Substance P, a potent vasodilatory neuropeptide, is released from peripheral nerve endings of sensory neurons by various stimuli. Although in vitro incubation of rat and human mast cells with substance P causes their degranulation, it is not known whether inflammatory changes induced by substance P are mediated by degranulation of mast cells. We investigated this point by using genetically mast cell-deficient WBB6F1-W/Wv and WCB6F1-Sl/Sld mice. The s.c. injection of substance P induced degranulation of mast cells in the skin of WBB6F1-+/+ mice, and then a marked eosinophil infiltration around the degranulated mast cells. However, WBB6F1-W/Wv and WCB6F1-Sl/Sld mice showed little or no eosinophil infiltration in the skin after the injection of substance P. When the mast cell deficiency of WBB6F1-W/Wv mice was rescued either systemically by bone marrow transplantation or locally by injection of cultured mast cells, injection of substance P induced the infiltration of eosinophils, suggesting that substance P-induced eosinophil infiltration was mediated through degranulation of mast cells.     

Dural Mast Cells: Source of Contaminating Histamine in Analyses of Mouse Brain Histamine Levels

Abstract: Histamine levels were determined in mouse brains from WBB6F₁- +/+ (mast cell normal) and WBB6F₁- W/W^v (mast cell-deficient) mice whose brains were dissected immediately after decapitation or after freezing the severed heads in liquid nitrogen for 10 s. In WBB6F₁-+/+ mice, brains obtained from frozen heads contained significantly higher levels of histamine than those obtained from unfrozen heads. The converse was found in brains obtained from the WBB6F₁- W/W^v mice. When CF-1 mice (which also contain brain-associated mast cells) were treated as described above, results very similar to those found with the WBB6F₁- +/+ mice were obtained. Further, the high levels of histamine found in CF-1 mice whose brains had been frozen in situ were accompanied by an extensive degranulation of mast cells in the dura mater of these mice. Because of this degranulation of mast cells, and the fact that increased levels of brain histamine were not found in mast cell-deficient mice, it is concluded that dural mast cells are the likely source of the artifactually higher levels of histamine seen in brains frozen in situ.     

Critical role for mast cells in the pathogenesis of 2,4-dinitrobenzene-induced murine colonic hypersensitivity reaction

The immunological mechanisms underlying the role of mast cells in the pathogenesis of inflammatory bowel disease (IBD) are poorly defined. In this study, non-IgE mediated colonic hypersensitivity responses in BALB/c mice induced by skin sensitization with dinitrofluorobenzene (DNFB) followed by an intrarectal challenge with dinitrobenzene sulfonic acid featured as a model to study the role of mast cells in the development of IBD. Vehicle- or DNFB-sensitized mice were monitored for clinical symptoms and inflammation 72 h after dinitrobenzene sulfonic acid challenge. DNFB-sensitized mice developed diarrheic stool, increased colonic vascular permeability, hypertrophy of colonic lymphoid follicles (colonic patches), and showed cellular infiltration at the microscopic level. Increased numbers of mast cells were found in the colon of DNFB-sensitized mice located in and around colonic patches associated with elevated levels of mouse mast cell protease-1 in plasma indicating mast cell activation. Colonic patches of DNFB mice, stimulated in vitro with stem cell factor indicated that an increase in TNF-alpha levels in the colon is mainly mast cell originated. Finally, neutrophil infiltration was observed in the colon of DNFB-sensitized mice. Induction of this model in mast cell-deficient WBB6F(1) W/W(v) mice shows a profound reduction of characteristics of the colonic hypersensitivity reaction. Reconstitution with bone marrow-derived mast cells in WBB6F(1) W/W(v) mice fully restored the inflammatory response. This study demonstrates the importance of mast cells in the development of clinical symptoms and inflammation in the presented murine model for IBD.     

Formation of mast cell colonies in methylcellulose by mouse peritoneal cells and differentiation of these cloned cells in both the skin and the gastric mucosa of W/Wv mice: evidence that a common precursor can give rise to both "connective tissue-type" and "mucosal" mast cells

We investigated the issue of mast cell heterogeneity by cloning mast cell colonies from peritoneal cells in methylcellulose, injecting the cloned cells into the skin and stomach of mast cell-deficient (WB X C57BL/6)F1-W/Wv (WBB6F1-W/Wv) mice, and staining the mast cells that developed in these sites with Berberine sulfate, a fluorescent dye that identifies heparin-containing mast cells. When peritoneal cells of nontreated WBB6F1-+/+ mice were plated in methylcellulose containing pokeweed mitogen-stimulated spleen cell conditioned medium, pure mast cell colonies developed. In contrast, the peritoneal cavity of genetically mast cell-deficient WBB6F1-W/Wv mice lacked the progenitor cells that made mast-cell colonies. The clonal nature of the mast cell colonies was determined by using the giant granules of C57BL/6-bgJ/bgJ mice as a marker: even when mixture of peritoneal cells of C57BL/6-bgJ/bgJ mice and C57BL/6-+/+ mice were plated, all of the resulting colonies consisted of either bgJ/bgJ-type mast cells alone or +/+-type mast cells alone. Individual mast c 11 colonies of WBB6F1-+/+ mouse origin were divided into two parts; one part was directly injected into the wall of the glandular stomach of a WBB6F1-W/Wv mouse, and another part was injected into the skin of the same W/Wv mouse. Injections of 14 of 46 such colonies resulted in development of mast cells in both the "connective tissues" (skin or stomach muscle or both) and the stomach mucosa. Mast cells in the connective tissues were stained with Berberine-sulfate, indicating that they contained heparin, whereas mast cells in the stomach mucosa were not. These results suggest that a single precursor cell can give rise to both "connective tissue-type" and "mucosal" mast cells.     

Protective roles of mast cells and mast cell-derived TNF in murine malaria

TNF plays important roles in the protection and onset of malaria. Although mast cells are known as a source of TNF, little is known about the relationship between mast cells and pathogenesis of malaria. In this study, mast cell-deficient WBB6F1-W/W(v) (W/W(v)) and the control littermate WBB6F1+/+ (+/+) mice were infected with 1 x 10(5) of Plasmodium berghei ANKA. +/+ mice had lower parasitemia with higher TNF levels, as compared with W/W(v) mice. Diminished resistance in W/W(v) mice was considered to be due to mast cells and TNF. This fact was confirmed by experiments in W/W(v) mice reconstituted with bone marrow-derived mast cells (BMMCs) of +/+ mice or of TNF-/- mice. W/W(v) mice with BMMCs of +/+ mice exhibit lower parasitemia and mortality accompanying significantly higher TNF levels than those of W/W(v) mice. Parasitemia in W/W(v) mice with BMMCs of TNF-/- mice was higher than that in +/+ mice. Activation of mast cells by anti-IgE or compound 48/80 resulted in release of TNF and decrease of parasitemia. In addition, splenic hypertrophy and increased number of mast cells in the spleen were observed after infection in +/+ mice and W/W(v) mice reconstituted with BMMCs of +/+ mice as compared with W/W(v) mice. These findings propose a novel mechanism that mast cells and mast cell-derived TNF play protective roles in malaria.     

Stem cell factor has a suppressive activity to IgE-mediated chemotaxis of mast cells

Stem cell factor (SCF), which is well known as a cytokine capable of amplifying development and functions of mast cells, is mainly released from fibroblasts in the peripheral tissue. To investigate whether SCF controlled chemotactic migration of mast cells induced by IgE-specific Ag, murine bone marrow-derived cultured mast cells (BMCMC) and human cord blood-derived cultured mast cells (HuCMC) were preincubated with SCF. Although BMCMC and HuCMC sensitized with IgE directly moved toward specific Ag, preincubation for even 1 h with an optimal dose of SCF suppressed the IgE-mediated chemotactic movement. No or little inhibitory effect of SCF was detected in BMCMC derived from c-kit receptor-defect WBB6F1-W/Wv mice. In contrast, preincubation of BMCMC and HuCMC with SCF enhanced beta-hexosaminidase release and Ca2+ mobilization in response to Ag after sensitization with IgE. Using the real-time record of chemotactic migration, BMCMC preincubated with SCF manifested motionless without degranulation. These results suggest that locally produced SCF may have an inhibitory effect on chemotaxis of mast cells, contributing to their accumulation and enhancement of functions at the peripheral site in allergic and nonallergic conditions.     

Key role for mast cells in nonatopic asthma

The mechanisms involved in nonatopic asthma are poorly defined. In particular, the importance of mast cells in the development of nonatopic asthma is not clear. In the mouse, pulmonary hypersensitivity reactions induced by skin sensitization with the low-m.w. compound dinitrofluorobenzene (DNFB) followed by an intra-airway application of the hapten have been featured as a model for nonatopic asthma. In present study, we used this model to examine the role of mast cells in the pathogenesis of nonatopic asthma. First, the effect of DNFB sensitization and intra-airway challenge with dinitrobenzene sulfonic acid (DNS) on mast cell activation was monitored during the early phase of the response in BALB/c mice. Second, mast cell-deficient W/W(v) and Sl/Sl(d) mice and their respective normal (+/+) littermate mice and mast cell-reconstituted W/W(v) mice (bone marrow-derived mast cells-->W/W(v)) were used. Early phase mast cell activation was found, which was maximal 30 min after DNS challenge in DNFB-sensitized BALB/c, +/+ mice but not in mast cell-deficient mice. An acute bronchoconstriction and increase in vascular permeability accompanied the early phase mast cell activation. BALB/c, +/+ and bone marrow-derived mast cell-->W/W(v) mice sensitized with DNFB and DNS-challenged exhibited tracheal hyperreactivity 24 and 48 h after the challenge when compared with vehicle-treated mice. Mucosal exudation and infiltration of neutrophils in bronchoalveolar lavage fluid associated the late phase response. Both mast cell-deficient strains failed to show any features of this hypersensitivity response. Our findings show that mast cells play a key role in the regulation of pulmonary hypersensitivity responses in this murine model for nonatopic asthma.     

Hybrid resistance to parental mast cell precursors in the skin of (WB X C57BL/6)F1-W/Wv mice

When bone marrow cells of (WB X C57BL/6)F1-+/+ (WBB6F1-+/+) and WB-+/+ (WB) mice were directly injected into the skin of genetically mast cell-deficient WBB6F1-W/Wv mice, mast cell clusters appeared at the injection sites. However, the number of WB bone marrow cells necessary for appearance of mast cell clusters was significantly larger than when bone marrow cells of WBB6F1-+/+ mice were used. When WB bone marrow cells were mixed either with WB thymus cells or with silica particles, the proportion of injection sites at which mast cell clusters appeared increased to the level that was observed after the injection of the same number of WBB6F1-+/+ bone marrow cells. When suckling WBB6F1-W/Wv mice of less than or equal to 18 days of age were used as recipients, bone marrow cells of WBB6F1-+/+ and WB mice produced mast cell clusters with a comparable efficiency. Both syngeneic thymus cells and silica particles are known to abrogate the hybrid resistance that is observed in the spleen against parental hematopoietic stem cells. The hybrid resistance in the spleen is not detectable in suckling mice, either. Thus, the poor growth of mast cell precursors in the skin and the poor growth of hematopoietic stem cells in the spleen seem to be regulated by the same mechanism.     

125I-fibrin deposition in IgE-dependent immediate hypersensitivity reactions in mouse skin. Demonstration of the role of mast cells using genetically mast cell-deficient mice locally reconstituted with cultured mast cells

We investigated the clotting associated with IgE-dependent immediate hypersensitivity reactions in the mouse by injecting monoclonal mouse anti-dintrophenyl IgE antibodies i.d. and, the next day, administering 125I-guinea pig fibrinogen i.v. 10 to 30 min before i.v. antigen (2,4-dinitrophenylated human serum albumin) challenge. In normal mice, 2-hr passive cutaneous anaphylaxis (PCA) reactions were associated with substantial leakage of 125I-fibrinogen and deposition of 125I-fibrin. Thus, ears injected with IgE contained up to six times the total cpm of 125I and up to 30 times the cross-linked 125I-fibrin-associated cpm of 125I than did control ears. Several lines of evidence indicated that the 125I-fibrin deposition associated with the PCA reactions was dependent on the activity of mast cells: 1) Mast cell degranulation occurred at sites of PCA reactions. 2) Antigen-induced influx of 125I-fibrinogen and deposition of 125I-fibrin were virtually abolished by heating the IgE (56 degrees C, 1 hr) before i.d. injection. 3) Little or no IgE-dependent 125I-fibrinogen influx or 125I-fibrin deposition occurred in mast cell-deficient WBB6F1-W/Wv or WCB6F1-S1/S1d mice X 4) Adoptive transfer of cutaneous mast cell populations into WBB6F1-W/Wv mice (by each of three approaches: i.v. transplantation of normal bone marrow cells or local i.d. injection of cultured, growth factor-dependent mast cells 2 days or 9 to 10 wk before antigen challenge) conferred on the recipients the ability to express the 125I-fibrinogen influx and 125I-fibrin deposition associated with PCA reactions. These data demonstrate that 125I-fibrinogen influx and 125I-fibrin deposition occurs in association with PCA reactions in the mouse, and that the reaction is largely or entirely dependent on the function of cutaneous mast cells. The experiments also demonstrate the utility of a novel model system for the analysis of mast cell function in vivo: WBB6F1-W/Wv mice locally reconstituted with mast cells by the injection of mast cell populations generated in vitro.     

Airway responses to chronic ozone exposure are partially mediated through mast cells.

Airways inflammation and epithelial injury induced by chronic ozone (O(3)) in genetically mast cell-deficient mice (Kit(W)/Kit(W-v)) were compared with those in mast cell-sufficient mice (+/+) and Kit(W)/Kit(W-v) mice repleted of mast cells (Kit(W)/Kit(W-v)-BMT). Mice were exposed to 0.26 ppm O(3) 8 h/day, 5 days/wk, for 1-90 days. Background was 0.06 ppm O(3). Age-matched mice were exposed to filtered air for O(3) controls. Reversibility of lesions was evaluated 35 days after exposure. Compared with Kit(W)/Kit(W-v), O(3) caused greater increases in lavageable macrophages, epithelial cells, and polymorphonuclear leukocytes in +/+ and Kit(W)/Kit(W-v)-BMT mice. O(3) also caused lung hyperpermeability, but the genotypic groups were not different. Cells and permeability returned to air control levels after O(3). O(3) induced lung cell proliferation only in +/+ and Kit(W)/Kit(W-v)-BMT mice; proliferation remained elevated or increased in +/+ and Kit(W)/Kit(W-v)-BMT mice after O(3). Greater O(3)-induced cell proliferation was found in nasal epithelium of +/+ and Kit(W)/Kit(W-v)-BMT mice compared with Kit(W)/Kit(W-v) mice. Results are consistent with the hypothesis that mast cells affect airway responses induced by chronic O(3) exposure.     

Proliferative potential of murine peritoneal mast cells after degranulation induced by compound 48/80, substance P, tetradecanoylphorbol acetate, or calcium ionophore A23187.

Proliferative potential of degranulated mast cells was investigated. Mast cells were collected from the peritoneal cavity of mice, and degranulation was induced by compound 48/80, substance P, 12-O-tetradecanoylphorbol 13-acetate (TPA), or calcium ionophore A23187. The potentiality of colony formation in methylcellulose was not reduced by treatment of various concentrations of compound 48/80, substance P and TPA. When degranulation was induced by compound 48/80, substance P or TPA, proportion of highly degranulated mast cells containing less than five granules was rather small. In contrast, considerable proportion of highly degranulated mast cells was obtained after the treatment with the low concentration (0.1 microgram/ml) of A23187. These highly degranulated mast cells, which were individually picked up by the micromanipulator, proliferated not only in methylcellulose but also in the skin of mast cell-deficient WBB6F1-W/Wv mice. Inasmuch as we have already shown the proliferation of IgE-sensitized and Ag-stimulated mast cells, degranulated mast cells appear to retain the proliferative potential in general.     

Opposing pharmacological actions of cepharanthin on lipopolysaccharide-induced histidine decarboxylase activity in mice spleens

A biscoclaurin alkaloid preparation, cepharanthin (Ceph), is reported to have opposing pharmacological effects, enhancement or depression, on several cells and tissues, although detailed mechanisms remain unclear. Previously, we reported that Ceph enhanced lipopolysaccharide (LPS)-induced histidine decarboxylase (HDC) activity in mice spleens by consecutive pre-administration. In this study, we examined the pharmacological effects on HDC activity of a single Ceph pre-administration to test the influence of the administration method. Consequently, HDC activities were decreased by a single administration 15 minutes before LPS challenge in ddY and ICR mice spleens. Moreover, to further examine this suppressing effect, we employed genetically mast cell-deficient WBB6F1 W/Wv (W/Wv) mice to avoid the influence of mast cells. In W/Wv mice, HDC activity was enhanced, but not in the congenic WBB6F1 +/+ mice. These findings suggest that mast cells influence the depressant effect on HDC activity by a Ceph single administration in mast cell sufficient mice.     

The role of mast cells in thioglycollate-induced inflammation

The possible role of mast cells in the initiation of inflammation was studied in genetically mast cell-deficient mice, WBB6F1-W/Wv. Inflammation was induced by i.p. injection of thioglycollate. The influx of neutrophils was markedly delayed in WBB6F1-W/Wv mice as compared to the WBB6F1-+/+, mice (congeneic controls). At the time (14 h) of maximum influx of neutrophils in WBB6F1-+/+ mice, thioglycollate caused a 3-fold increase in the total cell number in the peritoneal lavage fluid, and the neutrophil count was elevated 14-fold. At the same time point in W/Wv mice, the total cell number in the peritoneal lavage fluid was not increased significantly and the neutrophils were increased only three- to four-fold. Not only was the neutrophil influx in WBB6F1-W/Wv mice delayed, but the length of time during which the neutrophil count was elevated in the peritoneal fluid was significantly shortened. Transfer (i.p.) of mast cells cultured from the bone marrow of congeneic controls corrected the delay in the neutrophil influx. The magnitude of the neutrophil influx in WBB6F1-W/Wv mice was equivalent to that of congeneic controls 9 days after mast cell repletion. Histologic studies were performed to follow the migration and differentiation of mast cells after adoptive transfer into WBB6F1-W/Wv mice. No connective tissue mast cells could be identified on day 9 when the inflammatory reaction was restored. Migration of mast cells into the tissue, as studied in the cecum, progressed steadily. On day 9 after adoptive transfer, the mast cell number was 38% of congeneic controls. Therefore, the increase in thioglycollate-induced neutrophil influx in WBB6F1W/Wv mice after mast cell repletion seemed to be correlated, at least to some extent, with the migration of mast cells into tissues and not with differentiation into connective tissue mast cells. However, a certain maturation and differentiation may have occurred. These results suggest that mast cells play an important role, although they do not seem to be the only cell type responsible for the initiation of inflammation.     

Mast cells are critical for the production of leukotrienes responsible for neutrophil recruitment in immune complex-induced peritonitis in mice

Mast cells are secretory cells strategically located in the vicinity of blood vessels where they can readily initiate and modulate various inflammatory processes, including plasma exudation and leukocyte infiltration. We have previously shown that 50% of the neutrophil influx during immune complex peritonitis in mice is due to mast cells. Eicosanoids are important mediators of various inflammatory processes including neutrophil infiltration. The possibility that mast cells are essential for the production of leukotrienes (LT) involved in the elicitation of neutrophils in immune complex peritonitis was investigated in mast cell-deficient, WBB6F1-W/WV, and normal, WBB6F(1-)+/+, mice. The time course and amounts of immunoreactive PGE2, 6-keto-PGF1 alpha, and TX3B2 released into the peritoneal exudates were similar in both sets of mice. LTB4 and LTC4 levels, however, were twofold higher in +/+ than in W/WV mice 2 h after stimulation. HPLC analysis of the peritoneal exudate confirmed the presence of leukotrienes. The 5-lipoxygenase inhibitor A-63162 blocked leukotriene production in a dose-dependent manner in both sets of mice. However, this compound caused a significant reduction (60%) of neutrophil infiltration only in WBB6F(1-)+/+ but not in the mast cell-deficient mice. Mast cell reconstitution of WBB6F1-W/WV mice restored the effect of A-63162 on PMN recruitment. These data suggest that mast cells in the vicinity of blood vessels are important for the synthesis of leukotrienes responsible for PMN recruitment.     

Mast cell-associated TNF promotes dendritic cell migration

Mast cells represent a potential source of TNF, a mediator which can enhance dendritic cell (DC) migration. Although the importance of mast cell-associated TNF in regulating DC migration in vivo is not clear, mast cells and mast cell-derived TNF can contribute to the expression of certain models of contact hypersensitivity (CHS). We found that CHS to FITC was significantly impaired in mast cell-deficient Kit(W-sh/W-sh) or TNF(-/)(-) mice. The reduced expression of CHS in Kit(W-sh/W-sh) mice was fully repaired by local transfer of wild-type bone marrow-derived cultured mast cells (BMCMCs), but was only partially repaired by transfer of TNF(-/)(-) BMCMCs. Thus, mast cells, and mast cell-derived TNF, were required for optimal expression of CHS to FITC. We found that the migration of FITC-bearing skin DCs into draining lymph nodes (LNs) 24 h after epicutaneous administration of FITC in naive mice was significantly reduced in mast cell-deficient or TNF(-/)(-) mice, but levels of DC migration in these mutant mice increased to greater than wild-type levels by 48 h after FITC sensitization. Mast cell-deficient or TNF(-/)(-) mice also exhibited significantly reduced migration of airway DCs to local LNs at 24 h after intranasal challenge with FITC-OVA. Migration of FITC-bearing DCs to LNs draining the skin or airways 24 h after sensitization was repaired in Kit(W-sh/W-sh) mice which had been engrafted with wild-type but not TNF(-/)(-) BMCMCs. Our findings indicate that mast cell-associated TNF can contribute significantly to the initial stages of FITC-induced migration of cutaneous or airway DCs.     

The importance of mast cells for the neutrophil influx in immune complex-induced peritonitis in mice

The role of mast cells in polymorphonuclear leukocyte (PMN) influx in Ag-antibody complex-induced peritonitis was evaluated in mast cell-deficient WBB6F1-W/Wv (W/Wv) mice and their normal littermates, WBB6F1-+/+ (+/+). Peritoneal cell influx was evaluated after i.p. injection of preformed immune complexes. The first significant elevation in the PMN count over PBS-treated controls in +/+ mice was observed 2 h after stimulation. During the period of maximum leukocyte concentrations (6 to 10 h), the increase in total cell count was 5-fold and in PMN 25-fold. In W/Wv mice the PMN influx started 2 h later than in the +/+ mice, and the maximum response (8 to 10 h) was only 50% of that in controls. Reconstitution of mast cells in W/Wv mice for 2 wk or more restored the PMN response to immune complexes. Mast cell release due to AG-antibody complexes was evaluated by measuring fluorescence intensity after berberine sulfate staining for heparin in mast cells from unstimulated as well as stimulated +/+ mice. There was a significant decrease in fluorescence intensity as early as 15 min after stimulation. By 30 min the fluorescence intensity had declined by 65%. This indicates extensive mast cell release that started before PMN mobilization. These experiments demonstrate that mast cells make a significant contribution to immune complex-induced inflammation.     

Mast cell mediation of muscle and pulmonary injury following hindlimb ischemia-reperfusion.

We have observed extensive mast cell degranulation in the reperfused hindlimb muscle of the mouse, accompanied by pathological changes within the muscle. As quantitated by the tissue:blood (125)I permeability ratio, both the hindlimbs and lungs exhibited a significant increment in permeability during hindlimb reperfusion. In lungs of the same mice, mast cell-derived chymase mMCP-1 coats alveolar macrophages, an event noted by us in acid-induced direct lung injury. Mast cells in the lung contain mMCP-1, whereas those in the muscle do not. Neither extensive muscle injury nor an increased pulmonary permeability index occurs in the mast cell-deficient W/W(v) mice. We conclude that the mast cell is a key mediator in both local ischemia-reperfusion injury (I-R) of muscle and consequent remote lung injury.     

Studies of the role of mast cells in contact sensitivity responses. Passive transfer of the reaction into mast cell-deficient mice locally reconstituted with cultured mast cells: effect of reserpine on transfer of the reaction with DNP-specific cloned T cells

The role of mast cells in the elicitation of contact sensitivity (CS) responses was evaluated by transferring different aliquots of the same preparations of immune lymph node cells (I-LNC) into naive, genetically mast cell-deficient (WBB6F1-W/Wv or WCB6F1-S1/S1d) mice and the corresponding congenic normal (+/+) mice. We found that the 24-hr CS responses elicited in the recipient mast cell-deficient mice were statistically indistinguishable from those in the congenic +/+ mice according to four different criteria: micrometer measurements of ear swelling, ratios of the weight or [125I]iododeoxyuridine-labeled leukocyte infiltration-associated cpm in challenged and contralateral control ears, and amount of 125I-fibrin deposition. We also transferred I-LNC into WBB6F1-W/Wv mice which, 5 months earlier, had undergone local repair of their mast cell deficiency by the intradermal injection (into the left ear only) of growth factor-dependent cultured mast cells derived from congenic +/+ mice. When 24-hr CS responses were elicited in both ears of these mice, the reactions in the mast cell-reconstituted left ears were similar to those in the mast cell-deficient right ears. We also found that treatment of antigen-specific cloned T cells with reserpine in vitro markedly impaired their ability to transfer reactivity for CS, providing further evidence that reserpine can interfere with the expression of T-cell-mediated responses through effects independent of its action on mast cells.     

Mast cells enhance the antibody-mediated injury of skin basement membrane in mice.

Immunologic basement membrane injury occurs in certain human diseases. We investigated the role of mast cells in the initiation of inflammation induced by selective deposition of antibody on the basement membrane in the skin. Intradermal injection of the antibody into mast cell-deficient WBB6F1-W/Wv mice and their congenic controls, WBB6F1-+/+, caused C (C3) deposition and tissue damage preferentially at the dermo-epidermal junction (basement membrane). Damage occurred earlier and was more extensive in normal than in WBB6F1-W/Wv mice. Hemorrhage in WBB6F1-W/Wv was reduced by 50%. In both groups of mice, a dose- and time-dependent neutrophil infiltration reached maximum at 8 h. At the peak, neutrophil accumulation in WBB6F1-W/Wv was only 50% of that in normal mice. Mast cell reconstitution of WBB6F1-W/Wv mice normalized the inflammatory response. Pretreatment with a 5-lipoxygenase inhibitor, A-63162, reduced neutrophil infiltration by 60% in normal but not in WBB6F1-W/Wv mice. Mast cell repletion restored the effect of A-63162. The results indicate that mast cells are important for the initiation of inflammation induced by the deposition of antibody on the basement membrane and the production of leukotrienes participating in neutrophil elicitation.