Ex utero harvest of hematopoietic stem cells from placenta/umbilical cord with an automated collection system

Hematopoietic stem cells (HSCs) from the human placenta and umbilical cord blood (UCB) provide a rich source of highly proliferative cells for many clinical uses with advantages over traditional sources like the bone marrow and periphery blood. However, the key current constraint with this source of HSCs is the inadequate number of HSCs cells that can be harvested in a single collection using current approaches, which render a large number of collections unusable on their own, even for pediatric patients. This paper will present the development of a device to enable more efficient harvesting of HSCs from placentas, which can be used ex utero, upon the discharge of placentas after deliveries. The device can be used to facilitate a two-fraction collection process. Results, in terms of mononucleated cells (MNCs) count, CD34+ cells count, as well as flow cytometry, will be furnished to verify the effectiveness of the developed system.

Leukotriene E4: perspective on the forgotten mediator

Leukotriene (LT) E(4) mediates many of the principal features of bronchial asthma, such as bronchial constriction, hyperresponsiveness, eosinophilia, and increased vascular permeability. Furthermore, it is the most stable of the cysteinyl leukotrienes (CysLTs) and can be active at the site of release for a prolonged time after its synthesis. There might be several reasons why LTE(4) has been forgotten. LTE(4) demonstrated low affinity for CysLT(1) and CysLT(2) receptors in equilibrium competition assays. It was less potent than other CysLTs in functional assays, such as calcium flux, in cells transfected with CysLT(1) and CysLT(2). The introduction of CysLT(1) antagonists into clinical practice diverted interest into CysLT(1)-related mechanisms, which were mediated mainly by LTD(4). However, experiments with animal models and human studies have revealed that LTE(4) has unique characteristics that cannot be explained by the current knowledge of CysLT(1) and CysLT(2). These activities include its potency relative to other CysLTs to increase airway responsiveness to histamine, to enhance eosinophilic recruitment, and to increase vascular permeability. Asthmatic airways also demonstrate marked in vivo relative hyperresponsiveness to LTE(4), especially in patients with aspirin-sensitive respiratory disease. This has stimulated a search for additional LT receptors that would respond preferentially to LTE(4) stimulation.

Identification of corticosteroid regulated genes in human Th2 cells (136.37)

Glucocorticoids (GCs) are the mainstay treatment for many inflammatory diseases including asthma, which in the majority of patients can be controlled by inhaled GC. The molecular mechanisms of this regulation are however still not fully understood, especially in the small percentage of corticosteroid insensitive patients, who fail to respond well to even high doses of GCs.

In order to gain a deeper understanding of the molecular mechanisms of GC mediated gene regulation we have performed microarrays on in vitro differentiated Th1 & Th2 cells treated with the synthetic GC Dexamethasone (Dex). Naïve human CD4+ T cells were cultured for 28 days under either Th1 or Th2 skewing conditions. At day 28 these highly polarised cells (>95% Th1 cells are IFNγ positive, and >50% Th2 cells are interleukin (IL)-5 positive) were activated in the presence or absence of Dex at 10-7M. The isolated total RNA was used to probe the U133Plus2 gene chip (n=2), and results were confirmed via quantitative real-time PCR (n=4).

Our results have identified 64 genes consistently altered > 2-fold by Dex treatment in differentiated human T cells. These genes include documented Dex targets such as GILZ and FKBP51, as well as some novel targets. We are currently identifying the pathways that these novel targets fall into, as well as investigating potential differences between to corticosteroid sensitive and insensitive asthmatic patients.

This work is funded by the MRC and Asthma UK.

Atypical anaphylactic reaction to Patent Blue during sentinel lymph node biopsy for breast cancer

INTRODUCTION

We present an unusual case of severe anaphylaxis to Patent Blue dye with atypical clinical features during sentinel lymph node biopsy (SLNB). The medical personnel involved with sentinel node biopsies should be alert, and familiar with this unusual entity. We also present current data from the literature.

CASE REPORT

During a wide local excision for primary breast cancer and SLNB, and early during the operation, the patient became severely tachycardic and hypotensive without any signs of urticaria, rash, oedema, or bronchospasm. Resuscitation required the addition of noradrenaline infusion followed by an overnight admission to the intensive care unit. Raised serum tryptase levels supported the diagnosis of anaphylactic shock while skin tests showed a severe reaction to Patent Blue dye.

CONCLUSIONS

Severe, life-threatening anaphylaxis to Patent Blue dye may present without obvious previous exposure to the dye and without the cardinal signs of oedema, urticaria and bronchospasm making the diagnosis and management of such cases challenging. Correct diagnosis and identification of the causative factor is important and requires a specific set of laboratory tests that are not commonly requested in every-day medical practice. It is not clear from the literature whether the condition is common enough to justify pre-operative prophylactic or diagnostic measures.

Therapeutic approaches for control of transcription factors in allergic disease

The inflammatory response observed in allergic disease involves multiple cell types but is orchestrated in part by the T(H)2 cytokines IL-4, IL-5, and IL-13. In recent years, the transcription factors that control the expression and function of these cytokines have been elucidated, including signal transducer and activator of transcription 6, GATA3, nuclear factor of activated T cells, and nuclear factor kappaB. These molecules are attractive targets for therapeutic intervention because they regulate the expression of numerous effector molecules and functions simultaneously. For instance, the immunosuppressive agents glucocorticoids and cyclosporin A both function by repressing the activity of transcription factors through a variety of mechanisms. In this review we examine the role of each transcription factor in allergic disease and discuss approaches that have been taken to therapeutically interfere with transcription factor function in allergic disease.

Induction of angiogenesis by airway smooth muscle from patients with asthma

RATIONALE

Airway remodeling in asthma involves accumulation of airway smooth muscle (ASM) and increased vascularity due to angiogenesis. Bronchial blood vessels and ASM are found in close proximity, and ASM releases multiple proinflammatory mediators, including vascular endothelial growth factor (VEGF).

OBJECTIVES

We examined whether release of proangiogenic mediators is increased in ASM from subjects with asthma and whether this is translated to induction of angiogenesis.

METHODS

Biopsy-derived ASM cells were cultured from 12 subjects with mild asthma, 8 with moderate asthma, and 9 healthy control subjects. Angiogenesis induced by cell-conditioned medium (CM) from ASM was evaluated in a tubule formation assay. Anti-CD31-labeled tubules were quantified by image analysis. Angiogenic factors in CM were quantified by antibody arrays and by enzyme-linked immunosorbent assay.

MEASUREMENTS AND MAIN RESULTS

Induction of angiogenesis by CM from unstimulated ASM was increased in subjects with mild asthma (twofold) and moderate asthma (threefold), compared with healthy CM (P < 0.001). Levels of angiogenic factors (VEGF, angiopoietin [Ang]-1, angiogenin) were similarly elevated in CM from subjects with asthma compared with that from healthy subjects (P < 0.05), whereas antiangiogenic factors (endostatin, Ang-2) were unchanged. VEGF, Ang-1, and angiogenin in combination increased vascularity (twofold, P < 0.01) in cultured intact biopsies. Selective VEGF immunodepletion abolished enhanced tubule formation by CM from asthmatic ASM (P < 0.01), but CM depletion of Ang-1 or angiogenin had no effect.

CONCLUSIONS

ASM cultured from subjects with mild or moderate asthma, but not from healthy control subjects, promotes angiogenesis in vitro. This proangiogenic capacity resides in elevated VEGF release and suggests that ASM regulates airway neovascularization in asthma.

Dynamic CT of portal hypertensive gastropathy: significance of transient gastric perfusion defect sign

AIM

To evaluate the "transient gastric perfusion defect" sign as a way of diagnosing portal hypertensive gastropathy (PHG) on multidetector computed tomography (CT).

MATERIALS AND METHODS

Ninety-two consecutive patients with cirrhosis underwent three-phase CT and endoscopy. Endoscopy was performed within 3 days of the CT examination. As controls, 92 patients without clinical evidence of chronic liver diseases who underwent CT and endoscopy were enrolled; the findings at endoscopy were used as a reference standard for patients with PHG. Two radiologists who were unaware of the results of the endoscopy retrospectively interpreted the CT images. PHG was diagnosed on dynamic CT if the transient gastric perfusion defect sign was present. The transient gastric perfusion defect was defined as the presence of transient, segmental or subsegmental hypo-attenuating mucosa in the fundus or body of the stomach on hepatic arterial imaging that returned to normal attenuation on portal venous or equilibrium-phase imaging. The frequency of the transient gastric perfusion defect sign was compared between these two groups using Fisher's exact test. The frequency, sensitivity, specificity, positive predictive values, and negative predictive values of the transient gastric perfusion defect sign were also compared between patients with PHG and without PHG in the cirrhosis group.

RESULTS

Nine patients of 92 patients with cirrhosis were excluded because of previous procedure or motion artifact; the remaining 83 patients with cirrhosis were evaluated. In the cirrhosis group, 40 (48.1%) of 83 patients showed the transient gastric perfusion defect sign. In the control group, none of the 92 patients showed the transient gastric perfusion defect sign. In the cirrhotic group, the frequency of the transient gastric perfusion defect sign was significantly higher in the patients with PHG (75%, 36/48) than in patients without PHG (11.4%, 4/35). The sensitivity, specificity, positive predictive values, and negative predictive values of the sign for CT diagnosis of PHG in the cirrhosis group were 75, 88.6, 90, and 72.1% respectively.

CONCLUSION

The transient gastric perfusion defect sign could be used as a relatively specific sign of PHG in patients with cirrhosis.

A decentralized control of interconnected systems using neural networks

We develop a decentralized neural-network (NN) controller for a class of large-scale nonlinear systems with the high-order interconnections. The controller is a mixed NN comprised of a conventional NN and a special NN. The conventional NN is used to approximate the unknown nonlinearities in the subsystem, while a special NN is used to counter the high-order interconnections. We prove that this NN structure can achieve a stable controller for the large-scale systems.

Role of cysteinyl leukotrienes in human allergen-specific Th2 responses induced by granulocyte macrophage-colony stimulating factor

BACKGROUND

The pro-inflammatory cytokine, granulocyte macrophage-colony stimulating factor (GM-CSF), which is elevated in the lungs of atopic asthmatic patients, has been shown to enhance major histocompatibility class II expression of alveolar macrophages (AM). We hypothesized that exposure of AM and monocytes from atopic asthmatic patients to GM-CSF would enhance their antigen presenting function, and investigated putative mechanisms for this effect.

METHODS

Alveolar macrophages were purified from bronchoalveolar lavage by plastic adherence. Monocytes and CD4(+) T cells were purified from peripheral blood by magnetic bead separation. Antigen-presenting cell (APC) were pretreated with GM-CSF, pulsed with allergen and cocultured with autologous T cells. T-cell proliferation was determined by tritiated thymidine incorporation and cytokine production by enzyme-linked immunosorbent assay.

RESULTS

Exposure of allergen-pulsed AM and peripheral blood monocytes to GM-CSF significantly increased allergen-specific T-cell proliferation and T helper 2 (Th2) cytokine production. The enhanced response was dependent on costimulation by CD86, but not CD80. Inhibition of the 5-lipoxygenase pathway abrogated GM-CSF-mediated upregulation by monocytes of allergen-specific interleukin-5 (IL-5) and IL-13 cytokine production. Blocking of the cysteinyl leukotriene receptor 1 (cysLT(1)) receptor by a specific receptor antagonist inhibited allergen-specific IL-5 production in response to GM-CSF pretreatment.

CONCLUSION

Exposure to GM-CSF enhanced the capacity of human APC from atopic asthmatic patients to induce allergen-specific Th2 responses by a mechanism involving cysLT. Novel immunotherapies, targeting production of GM-CSF or its actions on APC have the potential, therefore, to prove beneficial in treatment of patients with inflammatory airway disease.

Clinical features, vascular risk factors, and prognosis for transient global amnesia in Chinese patients

BACKGROUND

Transient global amnesia (TGA) is an intriguing clinical syndrome that has not been studied in a series of Chinese patients.

METHODS

From 1989 to 1995, we observed 28 consecutive patients with TGA. Their clinical characteristics, risk factors, and outcome were retrospectively reviewed and analyzed.

RESULTS

There were 13 men and 15 women with a mean age of 62 years (range, 39 to 76). The duration of amnesic attack ranged from 20 minutes to 24 hours (mean, 8 hours), with the majority (76%) of attacks lasting for 2 to 12 hours. In 9 (32%) of the 28 patients, the TGA was triggered by a potential precipitating factor including bathing, emotional stress, and headache. The most prominent symptom exhibited by patients during an attack was repetitive questioning, which occurred in 21 (75%) of the 28 patients. No focal neurological abnormality was noted during or after the attack. Electroencephalograms were obtained in 26 patients after experiencing TGA, which showed nonspecific findings in 6 patients and were normal in 20. In 21 patients who had cranial computed tomography scans, cortical atrophy was found in 5 (24%), focal infarction in 4 (19%), and the results were negative in 12 (57%). Hypertension was the predominant vascular risk factor (11 cases, 39%), then hyperlipidemia (7 cases, 25%), and smoking (3 cases, 11%). No vascular risk factor was found in 13 patients (46%). Recurrent TGA was found in 5 patients (18%), and stroke in 2 (7%).

CONCLUSION

Our study largely confirms the demographic pattern, clinical characteristics, and prognosis of TGA patients reported from the western countries. Although the cause is uncertain, TGA is a relatively benign entity.

Evaluation of the biliary tract: The value of performing magnetic resonance cholangiopancreatography in conjunction with a 3-D spoiled gradient-echo gadolinium enhanced dynamic sequence

The 3-D gradient-echo (GRE) sequence allows thinner sections and better resolution of biliary obstruction. When the presence of biliary obstruction is identified using magnetic resonance cholangiopancreatography, the addition of the 3-D GRE sequence may be helpful for diagnosing biliary obstruction. By showing the changes in the bile duct wall, within the duct lumen and around the bile duct, this technique can be helpful for distinguishing benign from malignant stricture as well as a stone from an enhancing intraluminal mass.

Human Th2 cells selectively express the orexigenic peptide, pro-melanin-concentrating hormone

Th1 and Th2 cells represent the two main functional subsets of CD4(+) T helper cell, and are defined by their cytokine expression. Human Th1 cells express IFNgamma, whilst Th2 cells express IL-4, IL-5, and IL-13. Th1 and Th2 cells have distinct immunological functions, and can drive different immunopathologies. Here, we show that in vitro-differentiated human Th2 cells highly selectively express the gene for pro-melanin-concentrating hormone (PMCH), using real-time RT-PCR, enzyme immunoassay, and Western blot analysis. PMCH encodes the prohormone, promelanin-concentrating hormone (PMCH), which is proteolytically processed to produce several peptides, including the orexigenic hormone melanin-concentrating hormone (MCH). PMCH expression by Th2 cells was activation responsive and increased throughout the 28-day differentiation in parallel with the expression of the Th2 cytokine genes. MCH immunoreactivity was detected in the differentiated Th2 but not Th1 cell culture supernatants after activation, and contained the entire PMCH protein, in addition to several smaller peptides. Human Th1 and Th2 cells were isolated by their expression of IFNgamma and CRTH2, respectively, and the ex vivo Th2 cells expressed PMCH upon activation, in contrast to the Th1 cells. Because Th2 cells are central to the pathogenesis of allergic diseases including asthma, expression of PMCH by activated Th2 cells in vivo may directly link allergic inflammation to energy homeostasis and may contribute to the association between asthma and obesity.

Regulation of GM-CSF expression by the transcription factor c-Maf

BACKGROUND

Inflammation is a key feature of asthma and allergic disease. The proinflammatory cytokines IL-4, IL-5, and IL-13 are clustered on chromosome 5q with GM-CSF in close proximity, and each of these cytokines has been implicated in the pathogenesis of inflammatory disease. Although the expression of IL-4, IL-5, and IL-13 is coordinately regulated, the T(H)2-associated transcription factor c-Maf is thought to be involved only in the regulation of IL-4, the cytokine thought to be the main driver of T(H)2 differentiation.

OBJECTIVE

We sought to determine whether c-Maf influenced the expression of proinflammatory cytokines other than IL-4 in the Jurkat human T-cell line.

METHODS

RT-PCR, ELISA, and promoter-driven CAT assays were used to determine the effect of c-Maf overexpression on cytokine genes. A biotinylated oligo pulldown assay was used to demonstrate recruitment of c-Maf to the GM-CSF promoter.

RESULTS

We found that in addition to induction of IL-4, c-Maf could upregulate GM-CSF expression at both mRNA and protein levels, and that c-Maf could strongly activate the promoters of GM-CSF and IL-4 but not IL-5. Recruitment of c-Maf to the -33 to -97 bp region of the GM-CSF promoter was demonstrated.

CONCLUSION

We propose a novel role for c-Maf in the transcriptional regulation of GM-CSF in human T cells.

CLINICAL IMPLICATIONS

These data suggest that c-Maf may be a therapeutic target affecting both IL-4 and GM-CSF.

Airway expression of calcitonin gene-related peptide in T-cell peptide-induced late asthmatic reactions in atopics

BACKGROUND

The mechanisms of late asthmatic reactions provoked in atopic asthmatics by allergen-derived T-cell peptide epitopes remain unclear. Previous studies showed no changes in airway eosinophils or mast cell products after peptide challenge. In the present study our aim was to measure calcitonin gene-related peptide (CGRP), neurokinin (NK)-A, and substance P (SP) in bronchoalveolar lavage fluid and bronchial biopsies (BB) after inhalation of allergen-derived T-cell peptide epitopes since these neuropeptides (NP) had not previously been evaluated in this chronic asthma model.

METHODS

Bronchoscopy, with BB and bronchoalveolar lavage (BAL), was performed in 24 cat-allergic subjects 6 h after inhalation of Fel d 1-derived peptides. Neuropeptides were measured in BAL by enzyme-linked immunosorbent assay and CGRP expression in the airways was assessed by immunohistochemistry and confocal microscopy.

RESULTS

Twelve subjects (termed 'responders') developed isolated late reactions. Calcitonin gene-related peptide, but not NK-A or SP, was significantly elevated in BAL in responders only. Biopsy studies showed that in virtually all responders peptide challenge induced marked increases in CGRP immunoreactivity in bronchial epithelial cells, infiltrating submucosal cells and in association with airway smooth muscle. Double immunostaining indicated that CGRP colocalized predominantly to CD3+/CD4+ and CD68+ submucosal inflammatory cells.

CONCLUSION

Calcitonin gene-related peptide, a potent vasodilator, is markedly up-regulated in the airways of atopic asthmatics during late-phase reactions provoked by inhalation of allergen-derived T-cell peptides.

Proangiogenic activity in bronchoalveolar lavage fluid from patients with asthma

RATIONALE

Asthmatic airways have an increased number and size of vascular structures, which contribute to airflow obstruction and hyperresponsiveness.

OBJECTIVES

We examined whether proangiogenic mediators are elevated in bronchoalveolar lavage fluid (BALF) from subjects with asthma and if this translated to induction of angiogenesis.

METHODS

Angiogenic activity in BALF from 12 healthy, nonatopic subjects and 10 atopic subjects with mild asthma was evaluated by examining tubule formation at 11 days in cocultures of human endothelial cells with dermal fibroblasts. Vascular structures were visualized by anti-CD31 labeling and quantified by image analysis. Angiogenic growth factors in BALF from healthy subjects and subjects with asthma were identified using antibody arrays and by ELISA.

MEASUREMENTS AND MAIN RESULTS

Angiogenic activity induced by BALF from healthy subjects was not different from basal tubule formation (p>0.05). However, induction of tubular structures by asthmatic BALF was 2.5-fold greater (p<0.001) compared with healthy samples. Similarly, levels of proangiogenic growth factors (angiogenin, vascular endothelial growth factor [VEGF], monocyte chemotactic protein-1) were increased approximately 2.5-fold (p<0.05) in BALF from subjects with asthma, whereas antiangiogenic factors (endostatin, Ang-2) were unchanged. A blocking anti-VEGF antibody abolished tubule formation induced by BALF from either healthy subjects or subjects with asthma (p<0.01). Immunodepletion of VEGF had no effect on basal tubule formation induced by healthy BALF but abrogated enhanced tubule formation by asthmatic BALF (p<0.01).

CONCLUSIONS

BALF collected from subjects with asthma but not healthy subjects is functionally active in promoting angiogenesis in vitro. The proangiogenic capacity of BALF from subjects with asthma resides in elevated VEGF derived from asthmatic airways. This observation supports VEGF as a key factor in vascular remodeling in asthma.

Class switch recombination to IgE in the bronchial mucosa of atopic and nonatopic patients with asthma

BACKGROUND

Class switching from IgM/IgG/IgA to IgE is required for B cells to express IgE. This requires class switch recombination in the Ig heavy-chain gene locus. It is generally believed that class switch recombination occurs in lymphoid tissue, but it was recently shown that class switching to IgE occurs in the nasal mucosa in allergic rhinitis.

OBJECTIVE

We aimed to determine whether class switching to IgE also occurs in the bronchial mucosa in asthma, and to look for possible differences/similarities between atopic and nonatopic asthma.

METHODS

We have used RT-PCR to examine epsilon immunoglobulin heavy-chain germline gene transcripts (GLTs; epsilonGLTs), epsilon circle transcripts (CTs; Ivarepsilon-Cmu CT or Ivarepsilon-Cgamma CT), and mRNA encoding the heavy chain of IgE (epsilon mRNA) and activation-induced cytidine deaminase (AID) in bronchial biopsies from atopic patients with asthma, nonatopic patients with asthma, atopic controls without asthma, and nonatopic controls without asthma (10 subjects in each group).

RESULTS

The varepsilonGLT and AID mRNA were detectable in the bronchial mucosa of subjects in all 4 groups. In contrast, Iepsilon-Cmu CT, Ivarepsilon-Cgamma CT, and epsilon mRNA were detectable in the bronchial mucosa of the majority of both atopic and nonatopic patients with asthma, but rarely in the controls without asthma.

CONCLUSION

The bronchial mucosa is a site primed in all individuals for class switching to IgE, because of B-cell expression of epsilonGLT and AID mRNA. However, it is only in patients with asthma, regardless of atopic status, that class switching to IgE occurs.

CLINICAL IMPLICATIONS

Our findings reveal prospects for local targeting of the Ig class switch mechanism in the management of atopic and nonatopic asthma.

The effect of environmental salinity on the protein expression of Na+/K+-ATPase, Na+/K+/2Cl- cotransporter, cystic fibrosis transmembrane conductance regulator, anion exchanger 1, and chloride channel 3 in gills of a euryhaline teleost, Tetraodon nigroviridis

Chloride transport mechanisms in the gills of the estuarine spotted green pufferfish (Tetraodon nigroviridis) were investigated. Protein abundance of Na(+)/K(+)-ATPase (NKA) and the other four chloride transporters, i.e., Na(+)/K(+)/2Cl(-) cotransporter (NKCC), cystic fibrosis transmembrane conductance regulator (CFTR), Cl(-)/HCO(3)(-) anion exchanger 1 (AE1), and chloride channel 3 (CLC-3) in gills of the seawater- (SW; 35 per thousand) or freshwater (FW)-acclimatized fish were examined by immunoblot analysis. Appropriate negative controls were used to confirm the specificity of the antibodies to the target proteins. The relative protein abundance of NKA was higher (i.e., 2-fold) in gills of the SW group compared to the FW group. NKCC and CFTR were expressed in gills of the SW group but not in the FW group. In contrast, the levels of relative protein abundance of branchial AE1 and CLC-3 in the FW group were 23-fold and 2.7-fold higher, respectively, compared to those of the SW group. This study is first of its kind to provide direct in vivo evidence of the protein expression of CLC-3 in teleostean gills, as well as to examine the simultaneous protein expression of the Cl(-) transporters, especially AE1 and CLC-3 of FW- and SW-acclimatized teleosts. The differential protein expression of NKA, chloride transporters in gills of the FW- and SW-acclimatized T. nigroviridis observed in the present study shows their close relationship to the physiological homeostasis (stable blood osmolality), as well as explains the impressive ionoregulatory ability of this euryhaline species in response to salinity challenges.

Aspirin challenge and desensitization for aspirin-exacerbated respiratory disease: a practice paper

Aspirin desensitization is indicated for patients who have aspirin-exacerbated respiratory disease and whose asthma and/or rhinosinusitis is suboptimally controlled with inhaled corticosteroids and leukotriene-modifying drugs. In this practice paper, the general requirements for aspirin desensitization are presented, the locations where desensitizations can be safely performed are outlined, prechallenge patient preparation is discussed, an oral aspirin challenge protocol is presented, treatment of adverse reactions is reviewed, and maintenance of aspirin desensitization is discussed.

The novel correlation of carbonic anhydrase II and anion exchanger 1 in gills of the spotted green pufferfish,Tetraodon nigrovirids

A novel relationship between branchial carbonic anhydrase II (CAII) and anion exchanger 1 (AE1) was investigated in the euryhaline spotted green pufferfish (Tetraodon nigroviridis). The immunoblots revealed that AE1 was only detected in the membrane fraction of gills while CAII can be probed both in the membrane and cytosol fractions of gills. CAII protein abundance in the membrane fraction is salinity dependent. Immunological detection of the membrane fraction CAII protein in gills showed 3.9-fold higher in the hyposmotic (freshwater) group than the hyperosmotic (seawater;35 per thousand) group. In contrast, there was no change in the protein level of cytosolic CAII between seawater and freshwater groups. The whole-mount immunocytochemical staining demonstrated that both AE1 and CAII were colocalized to the Na(+)/K(+)-ATPase-immunoreactive cells in gill epithelium of the pufferfish. The interaction between CAII and AE1 was further identified by co-immunoprecipitation because AE1 was detected in the immunoprecipitates of CAII and vice versa. Our results showed that in pufferfish gills CAII was not only expressed in the cytosol to produce the substrate for AE1 transport during Cl(-) influx but also associated with the plasma membrane via AE1. Obviously, it is essential for the physiological function of AE1 to interact with CAII in the membrane of gill Na(+)/K(+)-ATPase-immunoreactive cells. To our knowledge, this is the first study to demonstrate the interaction of branchial CAII and AE1 in fish. The novel correlation proposed a new model of Cl(-)/HCO(3) (-) transport in gills of the teleosts.