Anatomical study of the adductor canal: three-dimensional micro-computed tomography, histological, and immunofluorescence findings relevant to neural blockade / 대한마취과학회지

Background@#A precise anatomical understanding of the adductor canal (AC) and its neural components is essential for discerning the action mechanism of the AC block. We therefore aimed to clarify the detailed anatomy of the AC using micro-computed tomography (micro-CT), histological evaluation, and immunofluorescence (IF) assays. @*Methods@#Gross dissections of 39 thighs provided morphometric data relevant to injection landmarks. Serial sectional images of the AC were defined using micro-CT and ultrasonography. The fascial and neural structures of the AC proper were histologically evaluated using Masson’s trichrome and Verhoeff-Van Gieson staining, and double IF staining using choline acetyltransferase (ChAT) and neurofilament 200 antibodies. @*Results@#The posteromedial branch insertion of the nerve to vastus medialis (NVM) into the lateral border of the AC proper was lower (14.5 ± 2.4 cm [mean ± SD] above the base of the patella) than the origin of the proximal AC. The AC consists of a thin subsartorial fascia in the proximal region and a thick aponeurosis-like vastoadductor membrane in the distal region. In the proximal AC, the posteromedial branch of the NVM (pmNVM) consistently contained both sensory and motor fibers, and more ChAT-positive fibers were observed than in the saphenous nerve (27.5 ± 11.2 / 104 vs. 4.2 ± 2.6 / 104 [counts/µm2], P < 0.001). @*Conclusions@#Anatomical differences in fascial structures between the proximal and distal AC and a mixed neural component of the neighboring pmNVM have been visualized using micro-CT images, histological evaluation, and IF assays.

Xenogeneic Humoral Immune Responses to Human Mesenchymal Stem Cells in Mice

Background and Objectives@#Many preclinical studies have been conducted using animal disease models to determine the effectiveness of human mesenchymal stem cells (hMSCs) for treating immune and inflammatory diseases based on the belief that hMSCs are not immunogenic across species. However, several researchers have suggested xenogeneic immune responses to hMSCs in animals, still without detailed features. This study aimed to investigate a xenogeneic humoral immune response to hMSCs in mice in detail. @*Methods@#and Results: Balb/c mice were intraperitoneally injected with adipose tissue-derived or Wharton’s jelly-derived hMSCs. Sera from these mice were titrated for each isotype. To confirm specificity of the antibodies, hMSCs were stained with the sera and subjected to a flow cytometic analysis. Spleens were immunostained for proliferating cell nuclear antigen to verify the germinal center formation. Additionally, splenocytes were subjected to a flow cytometric analysis for surface markers including GL-7, B220, CD4, CD8, CD44, and CD62L. Similar experiments were repeated in C57BL/6 mice. The results showed increased IgG 1 and IgG 2a titers in the sera from Balb/c mice injected with hMSCs, and the titers were much higher in the secondary sera than in the primary sera. These antibodies were specifically stained the hMSCs. Germinal centers were observed in the spleen, and flow cytometric analysis of the splenocytes showed higher frequencies of centroblasts (B220 ＋ GL7 ＋ ) and memory T cells (CD62L ＋ CD44 ＋ ) both in CD4 ＋ and CD8 ＋ subsets. Similar results were obtained for C57BL/6 mice. @*Conclusions@#hMSCs induced a humoral immune response in mice, with characters of T cell-dependent immunity

Vitamin C is taken up by human T cells via sodium-dependent vitamin C transporter 2 (SVCT2) and exerts inhibitory effects on the activation of these cells in vitro / 대한해부학회지

Vitamin C is an essential micronutrient that affects immune responses. T cells are one of the main players in acquired immunity and have been reported to be influenced by in vivo vitamin C supplementation. Yet, the way by which T cells uptake vitamin C and what direct effects vitamin C exerts on the cells are not known. To elucidate, we isolated human peripheral blood T cells and analyzed the expression of sodium-dependent vitamin C transporters (SVCT). T cells were activated in vitro in the absence or presence of vitamin C, before or after activation. As results, human T cells expressed SVCT2, but not SVCT1, and the expression level increased following activation. Vitamin C added in the culture media generally did not affect T-cell behaviors following activation, such as proliferation, apoptosis, expression of CD25 and CD69, and interleukin 2 secretion, regardless whether it was added before or after activation. However, exceptionally, high concentration vitamin C, when it was added before activation, but not after activation, did exert toxic effects on cell activation with respect to the above-mentioned parameters. In conclusion, we showed the expression of SVCT2 in human T cells for the first time. Vitamin C exerted toxic effects, at least in vitro, when the concentration was high and when it was given before activation. These toxic effects are not thought to be via anti-oxidant effects of vitamin C.

The Anti-inflammatory Effect of GV1001 Mediated by the Downregulation of ENO1-induced Pro-inflammatory Cytokine Production

GV1001 is a peptide derived from the human telomerase reverse transcriptase (hTERT) sequence that is reported to have anti-cancer and anti-inflammatory effects. Enolase1 (ENO1) is a glycolytic enzyme, and stimulation of this enzyme induces high levels of pro-inflammatory cytokines from concanavalin A (Con A)-activated peripheral blood mononuclear cells (PBMCs) and ENO1-expressing monocytes in healthy subjects, as well as from macrophages in rheumatoid arthritis (RA) patients. Therefore, this study investigated whether GV1001 downregulates ENO1-induced pro-inflammatory cytokines as an anti-inflammatory peptide. The results showed that GV1001 does not affect the expression of ENO1 in either Con A-activated PBMCs or RA PBMCs. However, ENO1 stimulation increased the production of pro-inflammatory cytokines such as tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, and IL-6, and these cytokines were downregulated by pretreatment with GV1001. Moreover, p38 mitogen-activated protein kinase (MAPK) and nuclear factor (NF)-kappaB were activated when ENO1, on the surface of Con A-activated PBMCs and RA PBMCs, was stimulated, and they were successfully suppressed by pre-treatment with GV1001. These results suggest that GV1001 may be an effective anti-inflammatory peptide that downregulates the production of pro-inflammatory cytokines through the suppression of p38 MAPK and NF-kappaB activation following ENO1 stimulation.

Opportunistic lung infections as a manifestation of Good's syndrome

Good's syndrome is an acquired immunodeficiency state associated with thymoma. It is characterized by recurrent infection, autoimmune disease, and immunologic abnormality. The insufficient immunity can be managed by intravenous immunoglobulin (IVIG) replacement therapy. We describe 2 patients who presented with Pneumocystis jiroveci pneumonia and Cytomegalovirus pneumonia after thymectomy for a thymoma. Immunologic study revealed hypogammaglobulinemia with very low B-cell count, consistent with Good's syndrome. They were successfully treated with trimethoprim/sulfamethoxazole and gancyclovir respectively, and they are all well without additional infections, receiving regular IVIG replacement.

A combinational effect of acetaminophen and oriental herbs on the regulation of inflammatory mediators in microglia cell line, BV2 / 대한해부학회지

The mechanism of Western medicine that is commonly used for pain relief is well-known. However, very little is known for oriental herbs, and even less is known for mixture of the two. We investigated the combinational effect of 3 kinds of oriental herbs, usually used for the control of headache, and acetaminophen to relieve headache in microglia cell line, BV2. Lipopolysaccharide (LPS) stimulation induced to produce nitrite and increased the expression of inflammation-related factors like inducible nitric oxide synthase and cyclooxygenase-2 (COX-2) in murine microglia cell line, BV2. Oriental herbs such as Angelica tenuissima, Angelica dahurica, and Scutellaria baicalensis reduced the production of nitric oxide and the expression of COX-2. Moreover, a treatment of acetaminophen combined with oriental herbs was more decreased the COX-2 expression, and its product, prostaglandin E2 production in BV2 cells. Therefore, a combined treatment of oriental herbs such as A. tenuissima, A. dahurica, and S. baicalensis and Western medicine like acetaminophen has a synergistic effect on the decrease of LPS-induced inflammation in microglia.

Students' perception of anatomy education at a Korean medical college with respect to time and contents / 대한해부학회지

Among medical education institutions worldwide, the time allotted for anatomy instruction has decreased without any reasonable time optimization suggestions. In addition, the utility of cadaver dissection has long been debated. Herein, we surveyed students' perceptions of anatomy education with respect to time and hands-on cadaver dissection, at Seoul National University College of Medicine. With the help of a questionnaire, we surveyed third- and fourth-year students at our institute who had completed the anatomy module as freshmen as well as their clinical clerkship. At our institute, students complete 50 hours of anatomy lectures and 120 hours of dissection laboratory during their first year. According to the survey responses, they generally considered these durations to be adequate for achieving their anatomy education goals. Almost all the students regarded the dissection laboratory as an essential and most helpful modality. Thus, we suggest that these ranges of time along with cadaver dissection could be useful guidelines for optimized anatomy education. The survey data also indicated that a more clinically oriented anatomy education could improve students' results.

Ascorbic acid insufficiency induces the severe defect on bone formation via the down-regulation of osteocalcin production / 대한해부학회지

The L-gulono-gamma-lactone oxidase gene (Gulo) encodes an essential enzyme in the synthesis of ascorbic acid from glucose. On the basis of previous findings of bone abnormalities in Gulo-/- mice under conditions of ascorbic acid insufficiency, we investigated the effect of ascorbic acid insufficiency on factors related to bone metabolism in Gulo-/- mice. Four groups of mice were raised for 4 weeks under differing conditions of ascorbic acid insufficiency, namely, wild type; ascorbic acid-sufficient Gulo-/- mice, 3-week ascorbic acid-insufficient Gulo-/- mice, and 4-week ascorbic acid-insufficient Gulo-/- mice. Four weeks of ascorbic acid insufficiency resulted in significant weight loss in Gulo-/- mice. Interestingly, average plasma osteocalcin levels were significantly decreased in Gulo-/- mice after 3 weeks of ascorbic acid insufficiency. In addition, the tibia weight in ascorbic acid-sufficient Gulo-/- mice was significantly higher than that in the other three groups. Moreover, significant decreases in trabecular bone volume near to the growth plate, as well as in trabecular bone attachment to the growth plate, were evident in 3- or 4-week ascorbic acid-insufficient Gulo-/-. In summary, ascorbic acid insufficiency in Gulo-/- mice results in severe defects in normal bone formation, which are closely related to a decrease in plasma osteocalcin levels.

Suppression of in vitro murine T cell proliferation by human adipose tissue-derived mesenchymal stem cells is dependent mainly on cyclooxygenase-2 expression / 대한해부학회지

Mesenchymal stem cells (MSCs) of human origin have been frequently applied to experimental animal models to evaluate their immunomodulatory functions. MSCs are known to be activated by cytokines from T cells, predominantly by interferon-gamma (IFN-gamma), in conjunction with other cytokines such as tumor necrosis factor-alpha (TNF-alpha) and interlukin-1beta. Because IFN-gamma is not cross-reactive between human and mouse species, the manner in which human MSCs administered in experimental animals are activated and stimulated to function has been questioned. In the present study, we established MSCs from human adipose tissue. They successfully suppressed the proliferation of not only human peripheral blood mononuclear cells but also mouse splenic T cells. When these human MSCs were stimulated with a culture supernatant of mouse T cells or recombinant murine TNF-alpha, they expressed cyclooxygenase-2 (COX-2), but not indoleamine 2,3-dioxygenase. The dominant role of COX-2 in suppressing mouse T cell proliferation was validated by the addition of COX-2 inhibitor in the co-culture, wherein the suppressed proliferation was almost completely recovered. In conclusion, human MSCs in a murine environment were activated, at least in part, by TNF-alpha and mainly used COX-2 as a tool for the suppression of in vitro T cell proliferation. These results should be considered when interpreting results for human MSCs in experimental animals.

CP-690550 Treatment Ameliorates Established Disease and Provides Long-Term Therapeutic Effects in an SKG Arthritis Model

Although pathogenesis of human rheumatoid arthritis (RA) remains unclear, arthritogenic T cells and downstream signaling mediators have been shown to play critical roles. An increasing numbers of therapeutic options have been added for the effective control of RA. Nevertheless, there is still a category of patients that fails treatment and suffers from progressive disease. The recently developed immunosuppressant CP-690550, a small molecule JAK kinase inhibitor, has been implicated as an important candidate treatment modality for autoimmune arthritis. In this study, we evaluated the therapeutic effect of CP-690550 on established arthritis using an SKG arthritis model, a pathophysiologically relevant animal model for human RA. CP-690550 treatment revealed remarkable long-term suppressive effects on SKG arthritis when administered to the well-advanced disease (clinical score 3.5~4.0). The treatment effect lasted at least 3 more weeks after cessation of drug infusion, and suppression of disease was correlated with the reduced pro-inflammatory cytokines, including IL-17, IFN-gamma, and IL-6 and increased level of immunoregulatory IL-10.

Vitamin C Is an Essential Factor on the Anti-viral Immune Responses through the Production of Interferon-alpha/beta at the Initial Stage of Influenza A Virus (H3N2) Infection

L-ascorbic acid (vitamin C) is one of the well-known anti-viral agents, especially to influenza virus. Since the in vivo anti-viral effect is still controversial, we investigated whether vitamin C could regulate influenza virus infection in vivo by using Gulo (-/-) mice, which cannot synthesize vitamin C like humans. First, we found that vitamin C-insufficient Gulo (-/-) mice expired within 1 week after intranasal inoculation of influenza virus (H3N2/Hongkong). Viral titers in the lung of vitamin C-insufficient Gulo (-/-) mice were definitely increased but production of anti-viral cytokine, interferon (IFN)-alpha/beta, was decreased. On the contrary, the infiltration of inflammatory cells into the lung and production of pro-inflammatory cytokines, tumor necrosis factor (TNF)-alpha and interleukin (IL)-alpha/beta, were increased in the lung. Taken together, vitamin C shows in vivo anti-viral immune responses at the early time of infection, especially against influenza virus, through increased production of IFN-alpha/beta.

The Analysis of Vitamin C Concentration in Organs of Gulo-/- Mice Upon Vitamin C Withdrawal

BACKGROUND: Vitamin C is an essential nutrient for maintaining human life. Vitamin C insufficiency in the plasma is closely related with the development of scurvy. However, in vivo kinetics of vitamin C regarding its storage and consumption is still largely unknown. METHODS: We used Gulo-/- mice, which cannot synthesize vitamin C like human. Vitamin C level in plasma and organs from Gulo-/- mice was examined, and it compared with the level of wild-type mice during 5 weeks. RESULTS: The significant weight loss of Gulo-/- mice was shown at 3 weeks after vitamin C withdrawal. However, there was no differences between wild-type and vitamin C-supplemented Gulo-/- mice (3.3 g/L in drinking water). The concentration of vitamin C in plasma and organs was significantly decreased at 1 week after vitamin C withdrawal. Vitamin C is preferentially deposited in adrenal gland, lymph node, lung, and brain. There were no significant changes in the numbers and CD4/CD8 ratio of splenocytes in Gulo-/- mice with vitamin C withdrawal for 4 weeks. And the architecture of spleen in Gulo-/- mice was disrupted at 5 weeks after vitamin C withdrawal. CONCLUSION: The vitamin C level of Gulo-/- mice was considerably decreased from 1 week after vitamin C withdrawal. Vitamin C is preferentially stored in some organs such as brain, adrenal gland and lung.

Vitamin C Up-regulates Expression of CD80, CD86 and MHC Class II on Dendritic Cell Line, DC-1 Via the Activation of p38 MAPK

Vitamin C is an essential water-soluble nutrient which primarily exerts its effect on host defense mechanisms and immune homeostasis, but the mechanism related to immune-potentiation is poorly understood. Since dendritic cells (DCs) are known as a potent antigen presenting cell (APC) that could enhance the antigen specific immune responses, we investigate the effects of vitamin C on activation of DCs and its related mechanism by using dendritic cell lines, DC-1. First, we found that there was no damage on DC-1 by 2.5 mM of vitamin C. In the presence of vitamin C, the expression of CD80, CD86, and MHC molecules was increased, but it was decreased by the pre-treatment of SB203580, p38 MAPK-specific inhibitor. We confirmed the phosphorylation of p38 MAPK was increased by the treatment of vitamin C. Taken together, these results suggest that vitamin C could enhance the activity of dendritic cells via the up-regulation of the expression of CD80, CD86, and MHC molecules and the activation of p38 MAPK is related to this process.

Identification of CM1 as a Pathogenic Factor in Inflammatory Diseases and Cancer

BACKGROUND: CM1 (centrocyte/-blast marker 1) was defined by a mAb against concanavalin A (Con A) activated PBMC. It is expressed in germinal center of human tonsil and on the surface of activated PBMC as well as cancer cells. Recently, increased productions of pro-inflammatory mediators were detected from activated PBMC by CM1 ligation. METHODS: However, there is a limitation to explain the exact role of CM1 on inflammation and its related mechanisms, since the identity of CM1 is still not clarified. In our previous study, we have already confirmed that soluble form of CM1 was produced by Raji. Therefore, we performed Q-TOF analysis after immunoprecipitation of concentrated Raji culture supernatant using anti-CM1 mAbs. RESULTS: As a result, we found that CM1 is identical to enolase-1(ENO1), a glycolytic enzyme, and we confirmed that results by silencing ENO1 using siRNA. It was also confirmed through competition assay between anti-CM1 and anti-ENO1 mAbs. Finally, we investigated the possible role of CM1 in inflammatory response and cancer. The ligation of CM1 on Raji cells with anti-CM1 mAbs induces the extensive production of prostaglandin E2(PGE2). In addition, the increased activity of matrix metalloproteinase (MMP)-2/9 was shown in NCI-N87, stomach cancer cell line by CM1 stimulation. CONCLUSION: CM1 is identical to ENO1 and it might be an important role in the regulation of inflammatory responses.

Mega-dose vitamin C attenuated lung inflammation in mouse asthma model / 대한해부학회지

Asthma is a Th2-dependent disease mediated by IgE and Th2 cytokines, and asthmatic patients suffer from oxidative stresses from abnormal airway inflammation. Vitamin C is a micro-nutrient functioning as an antioxidant. When administered at a mega-dose, vitamin C has been reported to shift immune responses toward Th1. Thus, we tried to determine whether vitamin C exerted beneficial effects in asthma animal model. Asthma was induced in mice by sensitizing and challenging with ovalbumin. At the time of challenge, 3~5 mg of vitamin C was administered and the effects were evaluated. Vitamin C did not modulate Th1/Th2 balance in asthma model. However, it decreased airway hyperreactivity to methacholine, decreased inflammatory cell numbers in brochoalveolar lavage fluid, and moderate reduction of perivascular and peribronchiolar inflammatory cell infiltration. These results suggest that vitamin C administered at the time of antigen challenge exerted anti-inflammatory effects. Further studies based on chronic asthma model are needed to evaluate a long-term effect of vitamin C in asthma. In conclusion, even though vitamin C did not show any Th1/Th2 shifting effects in this experiment, it still exerted moderate anti-inflammatory effects. Considering other beneficial effects and inexpensiveness of vitamin C, mega-dose usage of vitamin C could be a potential supplementary modality for the management of asthma.

Vitamin C acts indirectly to modulate isotype switching in mouse B cells / 대한해부학회지

Vitamin C, one of essential micronutrients, has been reported to modulate the humoral immune responses in some mammals. We investigated whether vitamin C might modulate this response in mice by directly affecting B cells. Splenic B cells were isolated and activated by CD40- and B cell receptor-ligation in vitro. The cells were cultured with a pretreatment of vitamin C from 0 to 1 mM of concentrations. Vitamin C slightly increased apoptosis of B cells dose-dependently and behaved as an antioxidant. We found that in vivo administration of vitamin C by intraperitoneal injection affected isotype switching as previously reported: the titer of antigen-specific IgG1 antibody was decreased, while that of IgG2a was unaffected. Somewhat different from those observed in vivo, in vitro exposure to vitamin C slightly decreased isotype switching to IgG1 and increased isotype switching to IgG2a. Pretreatment with vitamin C in the safe range did not affect either proliferation of cultured B cells or the expression of CD80 and CD86 in those cells. Taken together, in vivo results suggest that vitamin C acts to modulate isotype switching in the mouse. However, because of our in vitro results, we suggest that the modulation exerted by vitamin C in vivo is by indirectly affecting B cells, perhaps by directly influencing other immune cells such as dendritic cells.

N-acetyl-L-Cysteine Inhibits Functional Activation of Mouse Bone Marrow-Derived Dendritic Cells / 대한해부학회지

N-acetyl-L-cysteine (NAC) is a thiol-containing compound and acts as a precursor for glutathione (GSH). It behaves as an antioxidant in mammalian cells and also exerts anti-inflammatory effects. NAC is also known to affect several immune cells including eosinophils, B cells, T cells, and dendritic cells (DC) in many aspects. Even though it has been reported that NAC inhibits DC activation and shifts the immune response to Th2, these studies exhibit some contradictory results in detail and do not give any information with respect to the induction of regulatory T cells. In this study, we re-analyzed the effects of NAC on DC during their activation. We also evaluated whether it induced T cell anergy, Th1/Th2 shift, or regulatory T cells. NAC suppressed the elevation of intracellular reactive oxygen species during DC activation. In parallel, it down-regulated surface expression of CD40 and CD86, suppressed the decrease of phagocytic function, lowered the secretion of cytokines such as IL-6, IL-10, and IL-12. All these effects showed dose-dependency. Thus, it seems likely that NAC inhibited DC activation with regard to their phenotype and cytokine secretion. When we evaluated the T cell-stimulating capacity of these NAC-DC, T cell proliferation and secretion of both Th1 (IFN-gamma) and Th2 cytokine (IL-5) were decreased. This implies that the T cell-stimulating activity of NAC-DC decreased without any shift to Th1 or Th2 cytokine (IL-5). The secretion of IL-10 and TGF-beta in the supernatants were also decreased, which suggests that the decrease of T cell proliferation and cytokine secretion is due to the induction of T cell anergy, rather than regulatory T cells.

A Case of Bronchus-Associated Lymphoid Tissue(BALT) Lymphoma Treated with Lobectomy / 결핵및호흡기질환

The bronchus-asociated lymphoid tissue(BALT) lymphoma is a low-grade primary malignant lymphoma that originates from bronchus associated lymphoid tissue. A 67-year-old woman was admitted for evaluation of cough, sputum, rhinorrhea which had persisted for one month. Physical examination showed decreased breathing sound on the left upper lung field. High resolution chest computed tomography demonstrated consolidation which showed air-bronchogram and surrounding ground glass opacity in left upper lobe. These findings implicated inactive tuberculosis, organizing pneumonia, or bronchiolo-alveolar carcinoma. The histologic findings from percutaneous needle aspiration biopsy revealed aggregated atypical small lymphoid cells with lymphoepithelial lesions. With immunohistochemical staining, the atypical lymphoid cells reacted positively with CD 20 antibody and negatively with CD 3 antibody. Thus, we could diagnosed her as a patient with BALT lymphoma. After left upper lobectomy, she has been well without recurrence of the disease for 14 months. In this country of Republic of Korea, it was the 1st case of BALT lymphoma surgically treated when histological diagnosis had been done. Based on this case, we wanted to demonstrate the importance of early histological diagnosis and treatment of BALT lymphoma.

Transtorming Growth Factor beta1 Induces Epithelial-to-Mesenchymal Transition of A549 Cells

Idiopathic pulmonary fibrosis (IPF) comprises an aggregate of mesenchymal cells. However, the cellular origin of these mesenchymal phenotypes remains unclear. Transforming growth factor beta1 (TGF-beta1) has been known as the main cytokine involved in the pathogenesis of IPF. We examined whether the potent fibrogenic cytokine TGF-beta1 could induce the epithelial-to-mesenchymal transition (EMT) in the human alveolar epithelial cell line, A549, and determined whether snail expression is associated with the phenotypic changes observed in the A549 cells. EMT was investigated with cells morphology changes under phase-contrast microscopy, western blotting, and indirect immunofluorescence stains. E-cadherin and transcription factor, snail, were also evaluated by measuring mRNA levels using reverse transcriptase-polymerase chain rection (RT-PCR) analysis. The data showed that TGF-beta1 induced A549 cells with epithelial cell characteristics to undergo EMT in a concentration-dependent manner. Following TGF-beta1 treatment, A549 cells induced EMT characterized by cells morphological changes, loss of epithelial markers Ecaherin and cytokeratin, increased stress fiber reorganization by F-actin, and cytokeratin replacement by vimentin. Although IL-1beta failed to induce A549 cells to undergo EMT, the combination of TGF-beta1 and IL-1beta showed synergy effects in cells morphology changes and the expression of mesenchymal markers. The snail expression study using RT-PCR analysis provided that loss of E-cadherin expression was associated with snail expression. Stimulation of A54 cells with TGF-beta1 plus IL-1beta revealed a higher level of snail expression. Our data showed that EMT of A549 cells might be closely associated with snail expression.

CM1 Ligation Induces Apoptosis via Fas-FasL Interaction in Ramos Cells, but via Down-regulation of Bcl-2 and Subsequent Decrease of Mitochondrial Membrane Potential in Raji Cells

BACKGROUND: CM1 (Centrocyte/-blast Marker I) defined by a mAb developed against concanavalin-A activated PBMC, is expressed specifically on a subpopulation of centroblasts and centrocytes of human germinal center (GC) B cells. Burkitt lymphoma (BL) is a tumor consisting of tumor cells with the characteristics of GC B cell. Previously we reported that CM1 ligation with anti-CM1 mAb induced apoptosis in Ramos (IgM(high)) and Raji (IgM(low)) cells. METHODS & RESULTS: In the present study, we observed that CM1 ligation with anti-CM1 mAb induced Fas ligand and Fas expression in Ramos cells, but not in Raji cells. Furthermore, anti-Fas blocking antibody, ZB4, blocked CM1-mediated apoptosis effectively in Ramos cells, but not in Raji cells. Increased mitochondrial membrane permeabilization, which was measured by DiOC6, was observed only in Raji cells. In contrast to no significant change of Bax known as pro-apoptotic protein, anti-apoptotic protein Bcl-2 was significantly decreased in Raji cells. In addition, we observed that CM1 ligation increased release of mitochondrial cytochrome c and upregulated caspase-9 activity in Raji cells. CONCLUSION: These results suggest that apoptosis induced by CM1-ligation is mediated by Fas-Fas ligand interaction in Ramos cells, whereas apoptosis is mediated by down-regulation of Bcl-2 and subsequent decrease of mitochondrial membrane potential in Raji cells.