Studies on the Interaction of Human Immunoglobulin E with Rat Mast Cells

The present study was undertaken to determine if human IgE immunoglobulin could be shown to bind to rat peritoneal mast cells and to establish whether binding is a prerequisite for the cellular alterations taking place during the rat mast cell test. It was found that sensitization of rat mast cells occurs very rapidly in the presence of human IgE immunoglobulin. Thus, incubation of the IgE immunoglobulin at 37°C for 3 min with rat mast cell suspension and washing the suspension once with medium 199 led to morphological changes in the mast cells on challenge with anti-human IgE immunoglobulin. However, attempts to correlate longer periods of incubation time with increased sensitization or show the extent of binding by multiple washings of the cell suspension were unsuccessful due to the lability of the rat mast cells. On the other hand, significant uptake of IgE immunoglobulin was observed by the mast cells after exposing the cell suspension to (a) radiolabelled ¹²⁵I-IgE immunoglobulin for 3 min at 37°C and washing the suspension and (b) IgE immunoglobulin for 3 min at 37°C, washing the cell suspension and challenging the cells with FITC-labelled anti-human IgE immunoglobulin. At 3 min exposure time, human IgE immunoglobulin was not bound by neutrophils or eosinophils nor was human IgG immunoglobulin bound by mast cells.     

发育中的胎儿十二指肠中肥大细胞的研究

目的与方法　用HE染色和甲苯胺蓝特殊染色研究胎儿十二指肠壁肥大细胞 (MC)的分布、发育规律、异质性。结果　 16周时 ,在胎儿十二指肠粘膜下层、肌层间结缔组织中偶见结缔组织型(CTMC) ,而粘膜型肥大细胞 (MMC)出现在 18周。TB染色 ,幼稚的MC颗粒呈淡紫色 ;分化成熟的MC呈紫色。某些MC自 2 2周开始呈活化状态 ,MC表面界限不清 ,有脱颗粒现象。结论　胎儿十二指肠MC有MMC和CTMC ,两者存在异质性     

Distribution Change of Mast Cells in Human Nasal Polyps

Recent studies have shown that mast cells are involved in pathophysiologic processes of chronic inflammation. However, little is known about the distribution of mast cells in nasal polyps, which is a chronic inflammatory disease of the upper airways. Biopsy specimens from patients with nasal polyps (n = 20) and control patients without nasal polyps (n = 8) were included in this study. The distribution of mast cells in nasal polyps was determined by immunohistochemistry. Meanwhile, we detected the expression of chemokines (CCL5, CCL11, CX3CL1, IL‐8, IL‐6) in the epithelial cells of normal nasal mucosa and nasal polyps. In addition, the expression of these chemokines was investigated by western bolting in airway epithelial cells line (A549 cells) under inflammatory condition. Mast cells migrated toward intraepithelium in nasal polyps and the expression of chemokines (CCL5, CCL11, CX3CL1, IL‐8) was up‐regulated in the epithelial cells of nasal polyps compared with normal nasal mucosa. The expression of chemokines was also up‐regulated in A549 cells after Lipopolysaccharide (LPS)‐treatment for 3 hr and 6 hr. Our findings showed that mast cells migrate toward intraepithelium in nasal polyps and the overexpression of chemokines (CCL5, CCL11, CX3CL1, IL‐8) suggested that they might be responsible for mast cells migration. It implies that mast cell play potential roles in the development of nasal polyps. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.     

Binding of Antigen to Surface to on Isolated Rat Mast Cells

This study concerns observations on isolated rat mast cells sensitized to specific antigen. Specific binding of antigen to the surface immunoglobulins of these cells could be demonstrated by immunofluorescence technique as well as by radiolabelled antigen binding and the degree of binding parallelled the allergic reaction as judged by histamine release. Exposure of mast cells to antigen at both low and high antigen concentrations did not change the distribution of the surface immunoglobulins. Furthermore, neither capping not shedding could be induced, even by excessive antigen stimulation. The amount of antigen molecules bound to surface Ig was linearly correlated to the allergic histamine release. When mast cells were sensitized to two antigens of different molecular weight, the cells showed the highest sensitivity to the antigen having the highest molecular weight. These results indicate that both the amount of antigen and the molecular weight of the antigen bound to surface Ig are important factors in the allergic histamine release from mast cells, whereas surface Ig redistribution is not.     

Preliminary Report on the Origin of Rat Mast Cells

Zusammenfassung Nach subcutaner Injektion von Kaninchenantirattenmakrophagenserum werden die Gewebsmastzellen der regionären Lymphknoten total zerstört. Die Lymphknoten bleiben für etwa 3 Tage mastzellenfrei. Danach treten Mastzellcnvorläufer auf, die morphologisch und cytochemisch Blutmonocyten oder jungen Makrophagen weitestgehend entsprechen. Aus diesen Beobachtungen und aus Literaturbefunden wird der Schluß gezogen, daß Gewebsmastzellen sehr wahrscheinlich aus Blutmonocyten entstehen.

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Summary After s.c. injection of rabbit anti-macrophage serum a total destruction of tissue mast cells in the regional lymph nodes was observed. The lymph nodes remained free from tissue mast cells until approximately the third day. Thereafter, mast cell progenitors appeared which morphologically and cytochemically corresponded closely to blood monocytes or young macrophages. From these observations and from experimental findings of the literature, it is concluded that tissue mast cells very probably originate from blood monocytes.

     

Inhibitory Effect of Cyclosporin A on Histamine Release from Human Leukocytes and Rat Mast Cells

The influence of cyclosporin A (CyA) on human basophil histamine release induced in vitro by specific antigen, anti-IgE, calcium ionophore A23187, or concanavalin A (Con A) was studied. CyA inhibited the release induced by these four stimulators. It is suggested that the drug acts directly on the target cell, since similar effect was obtained with isolated peritoneal rat mast cells. The basophil histamine release was not changed by a non-immunosuppressive cyclosporin derivate.     

Association between KIR genotypes and HLA-B alleles on viral load in Southern Brazilian individuals infected by HIV-1 subtypes B and C

There is a great variety of HIV-1 subtypes circulating in Brazil, including subtype C, whose prevalence is on the rise, particularly in the southern region. Many host and viral genetic factors may be involved in this trend. We evaluated the influence of human leukocyte antigen (HLA) class I alleles and killer-cell immunoglobulin-like receptor (KIR) genotypes on viral set point and T-CD4⁺ parameters in 84 treatment-naïve HIV-1-positive individuals. Frequency data in the infected group were compared to data of 548 healthy control subjects. Individuals with the KIR AA genotype had a higher viral load (VL) than individuals with the KIR Bx genotype. The HIV-1 group was subdivided into three subgroups according to HLA-B allele presence: those with protection to disease alleles (HLA-B⁺), accelerated disease progression alleles (HLA-B⁻), or neither (HLA-B^o) were grouped. We observed a significant effect of the HLA-B allele presence on VL. The HLA-B⁺ group had significantly lower VL than the HLA-B⁻ group and trended toward a lower VL than the HLA-B^o group. There were significant differences between groups expressing extreme VL values: KIR-AA + HLA-B⁻ vs. KIR Bx + HLA-B⁺ and KIR-AA + HLA-B^o vs. KIR Bx + HLA-B⁺. The relationship of KIR/HLA host genetics with slow HIV disease progression in southern Brazil may be useful for vaccine developers, epidemiologists, and clinicians.     

Nerve Growth Factor Immunoreactivity of Mast Cells in Acute Involuted Human Thymus

The acute involution of the thymus is induced by either exogenous or endogenous factors, including some infections (infection type involution). The present study was focused on both detection and immunocytochemical analysis of NGF immunopositive mast cells in child thymus with acute infection-induced involution. Autopsy thymus specimens from children with infection diseases (Sepsis, Encephalomyelitis, Varicella) were examined at light and electron microscopic level and compared to normal infantile thymuses. We observed a redistribution of NGF immunopositive mast cells in infection-affected child thymus, which lobular architecture was collapsed. A positive correlation between the degree of the involutive changes, increased distribution and enhanced NGF immunoreactivity of mast cells was defined. The possible involvement of NGF immunopositive mast cells in the process of acute thymus involution is discussed.     

人胎儿胃肥大细胞的研究

观察了 40例不同胎龄胎儿胃底部两型肥大细胞发育、数量及分布和胃底部发育的关系 ,并探讨了甲醛固定对 CTMC和 MMC染色效应的影响。发现人胎儿胃 CTMC出现于受精后 13～ 16周的粘膜下层等处 ,主要分布在胃粘膜固有层近粘膜肌处 ,数量随粘膜层胃底腺及粘膜肌等结构的发育而增加。两型肥大细胞对甲醛固定的反应无明显差异。本文就肥大细胞在胃底部发育过程中的意义进行了讨论     

Intraepithelial Infiltration by Mast Cells in Human Helicobacter pylori Active Gastritis

Recent observations suggest an involvement of mast cells in Helicobacter pylori gastritis, but the mechanism of intraepithelial mast cell activation in H. pylori-infected patients remains to be clarified. Intraepithelial mast cells, identified by immunohistochemistry for CD117, were quantified in antral biopsies from 6 patients with H. pylori “active” chronic gastritis, 7 patients with H. pylori “nonactive” gastritis, and 9 controls. Antral biopsies from patients with H. pylori “active” gastritis showed higher intraepithelial mast cell counts than those from patients with H. pylori “nonactive” gastritis and from controls. Electron microscopy, selectively performed in 6 cases of H. pylori “active” gastritis, confirmed the presence of intraepithelial mast cells and allowed their subdivision into mature cells with intact electron-dense granules or degranulated cells. Other mast cells appeared to migrate through defects in the basement membrane into the epithelial layer. Mast cells in these areas often showed piecemeal degranulation or were characterized by large canaliculi, expanded Golgi areas, and a few granules, a process similar to the phase of recovery from anaphylactic degranulation of isolated human mast cells. The possible significance of these unusual ultrastructural findings is discussed.     

Binding of Antigen to Surface Ig during in vitro Hyposensitization of Isolated Rat Mast Cells

The mechanism of in vitro hyposensitization was examined in isolated rat mast cells. Surface distribution of immunoglobulin was examined by immunofluorescence technique. Hyposensitization could be ascribed neither to changes in the distribution of surface immunoglobulins nor to capping or shedding phenomena. The distribution of cell-bound antigen and the number of antigen-positive cells (patch-bearing cells) was not changed by hyposensitization. The binding of antigen to surface Ig was quantitated by I125-labelled antigen. In rats sensitized to two different antigens, hyposensitization of the mast cells with one of these inhibited the subsequent histamine release induced by either of the two antigens, whereas no changes were observed in the antigen binding capacity. The present investigation indicates that the mechanism of in vitro hyposensitization is the result of events secondary to the initial binding of antigen to the mast cell surface immunoglobulin.     

Mast Cells and the Adaptive Immune Response

Background  The idea that the innate and adaptive immune systems are not separate entities is no longer new. In fact, it is surprising that this paradigm was accepted without question for so long. Many innate cells express cell surface molecules and soluble mediators that are essential for the development and activation of T cells and B cells. Yet among the innate cell populations, mast cells may play the major role in regulating adaptive immune cell function. Discussion  This role first came to light in studies of mast cells and their involvement in the autoimmune disease experimental allergic encephalomyelitis, the major rodent model of multiple sclerosis and has subsequently been verified in many in vitro and in vivo model systems.     

Mast Cells Appearing in Long‐term Skeletal Muscle Cell Cultures of Rat

Mast cells are known to be involved in type I allergy and to be localized in almost all tissues in the body. However, they have slightly different properties depending on their tissue of residence. Although mast cells are found in skeletal muscle tissue, there have been no reports of their appearance in cultured skeletal muscles. We report here that mast cells appear in long‐term cultures of skeletal muscles from neonatal rats and rat fetuses. When muscle cells were disseminated and cultured in minimum essential medium with 10% fetal calf serum and 10% horse serum, oval cells containing large granules started to appear on myotube sheets at 5 days of culture. These oval cells continued to proliferate for 2–3 months, and showed immunoreactivity for histamine, tryptase, Fc_εRI, and c‐kit. They showed metachromatic staining with 0.5% toluidine blue at pH 0.5 and were stained with both Alcian blue and safranin. Biochemically measured histamine content per dish was significantly higher in 2‐month than in 5‐day culture. From these results, we concluded that these oval cells were mast cells. Because proteases from mast cells have been reported previously to affect myoblast proliferation, the present findings suggest that there may be some interaction between mast cells and muscle cell proliferation or differentiation. The present finding that mast cells are easily obtained from ordinary skeletal muscle cultures provides a useful method for the study of the diverse functions of mast cells. Anat Rec, 1424‐1430, 2007. © 2007 Wiley‐Liss, Inc.     

The Influence of IgE on Cultured Human Mast Cells

Purpose

The mast cell plays a pivotal role in the human immune response. Crosslinking of 2 IgE molecules bound to the high affinity IgE receptor (FcεRI) on the surface of the mast cell results in mast cell degranulation and the release of several proinflammatory mediators. Patients with type-I allergy have increased levels of IgE in the blood compared to healthy individuals.

Methods

In a 6-week culture system of stem cells to human mast cells we investigated the effect of the concentration of IgE. The mast cells were cultured with different concentrations of IgE for the last 10 days of the maturation period. It was observed how the IgE concentration affects the histamine release, FcεRI density on the mast cell surface and the concentration of other mediators.

Results

A clear correlation between IgE concentration in culture medium and the release of histamine upon activation was observed. It showed a bell-shaped dose response curve, with maximal response around an IgE-concentration of 250 ng/mL. Furthermore, the sensitivity of the mast cells and surface density of FcεRI on mast cell surface was also influenced by the IgE concentration in the culture medium.

Conclusions

IgE in the culture medium during the last 10 days of mast cell maturation influences the release of the preformed mediator histamine after mast cell activation and the density of FcεRI on the mast cell surface. The release of the de novo synthetized mediator prostaglandin D₂ and the expression of chymase and tryptase are not influenced by IgE in culture medium.     

Human Neural Stem Cells Normalize Rat Behavior after Hypoxia

Transplants of cultured neural stem cells from human brain survived, retained multipotent activity, and produced a neuroprotective effect on degenerating neurons in the brain of adult rats subjected to hypoxic hypoxia. They normalized animal behavior and improved conditioning in two-way avoidance response paradigm in a shuttle box.     

Effect of Salmonella Bacteria on the Interaction of Human NK Cells with Endothelial Cells

Leukocyte-endothelial cell adhesion and its regulation are essential and complex initial aspects of lymphocyte migration. Various factors (IL-1, TNF-alpha, IFN-gamma etc.) have been shown to increase the endothelial adhesiveness for human lymphocytes, including natural killer cells (NK cells). In this work we have demonstrated that pretreatment of either the target endothelial cell monolayers or the binding LGL-cells with mR595 Salmonella Minnesota bacteria results in a substantial increase in the adhesiveness of LGL-cells to endothelial cells. The increase was more prominent when the endothelial cells were treated than when the adhering LGL-cells were similarly pretreated. The adhering cell population was significantly enriched with CD56 (Leu19) and CD16 positive cells, i.e. cells with NK cell phenotype, when the lymphocyte population was pretreated. However, the pretreatment of EC resulted in a non-specific increase in EC adhesiveness since the relative proportion of CD56+ (Leu19), CD16+ and CD3+ cells among the adhering cells did not significantly differ from the starting population. The bidirectional enhancement of adhesiveness of human NK cells to endothelium by mR595 Salmonella bacteria may be significant in the host defense responses against microbial infections.     

Changes in Mast Cells of Vascular Plexuses of Human Cerebral Ventricles in Atherosclerosis of Precerebral Arteries

Scanty mast cells with high saturation and weak degranulation located perivascularly and in the subepithelial zone of the villi were detected in vascular plexuses of human brain. Cerebral atherosclerosis was associated with pronounced changes in their morphofunctional organization: changed shape, decreased volume and index of saturation and degranulation, predominating in the villous part of the vascular plexus of the lateral ventricle. __________ Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 140, No. 11, pp. 584–586, November, 2005     

Characterization of ERK Activation in Human Mast Cells Stimulated by Contact with T Cells

Close physical proximity between mast cells and T cells has been demonstrated in several human conditions. We have identified and characterized a novel mast cell activation pathway initiated by contact with T cells, and showed that this pathway is associated with cytokine release. It has been shown recently that Ras is activated in this pathway. Thus, in the present study we further explore the downstream events associated with Ras activation and cytokine release in human mast cells stimulated by contact with T cells. ERK activation in human mast cells stimulated by either contact with T cells or by crosslinking the FC epsilon receptor was studied. Photobleaching experiments were used to study ERK localization. Enzyme linked immunosorbent assay was used to study the cytokine release by human mast cells. We show that stimulation of human mast cells by contact with activated T cells results is sustained ERK activation. Furthermore, sustained ERK activation in these cells is associated with increased dwell time at the nucleus and with IL-8 release. Interestingly, when mast cells were stimulated by crosslinking the FC epsilon receptor I, ERK activation was transient. ERK activation was associated with a shorter dwell time at the nucleus and with TNF-α release. Thus, retaining ERK in the nucleus might be a mechanism utilized by human mast cells to generate different cytokines from a single signaling cascade.     

Transplantation of Cultured Human Neural Progenitor Cells into Rat Brain: Migration and Differentiation

We studied the fate in vitro cultured human stem/progenitor cells after transplantation into rat brain. The cells from human fetuses at 8-12 weeks' gestation were cultured in vitro for 14 days and transplanted into the brain of 10-day-old and adult rats. Microscopic examination showed that human stem/progenitor cells migrated into various regions of rat brain. Immunohistochemical assay demonstrated that some cells differentiated into astrocytes and neurons, while others retained the embryonic phenotype.     

Immunoregulatory Function of Human Cord Blood Lymphocytes on Immunoglobulin Production

ABSTRACT: The functional maturity of human umbilical cord blood B lymphocytes and the immunoregulatory activity of cord T lymphocytes were assessed by measuring the in vitro immunoglobulin production by B cells from either cord or adult blood. Supernatants from 48-hr pokeweed-mitogen (PWM) stimulated cord or adult lymphocyte cultures were added to cord or adult B cell cultures in the presence of PWM; a significant amount of immunoglobulin was produced in adult B cell cultures only. Adult B or T cells were then cocultured with cord T or B cells; a significant amount of immunoglobulin was again found only in adult B cell cultures. These results indicated that cord B cells were functionally immature and that cord helper T cell function was adequate but masked by excessive suppressor activity. Indeed, addition of cord T cells but not of allogeneic adult T cells to PWM stimulated adult lymphocyte cultures inhibited their immunoglobulin production; this confirmed cord T cells' increased suppressor activity. Cord T cells were not intrinsically suppressive since they failed to suppress immunoglobulin production by Epstein-Barr Virus (EBV) transformed B cells. They could be activated, however, by PWM or allogeneic cells (in mixed lymphocyte cultures) and their effect was mediated via soluble factor(s) as demonstrated by the suppressor effect of these culture supernatants on immunoglobulin production by unfractionated adult lymphocytes. In contrast, when these supernatants were added to T cell-depleted adult lymphyocyte cultures, enhancement rather than suppression was observed. These results indicated that the soluble factor(s) released by Cord T lymphocytes was not suppressing per se but induced suppression through activation of suppressor cells.