Senescence markers in focal nodular hyperplasia of the liver: pathogenic considerations on the basis of immunohistochemical results.

Focal nodular hyperplasia (FNH) is a polyclonal tumour-like hepatic lesion characterised by parenchymal nodules, connective tissue septa without interlobular bile ducts, pronounced ductular reaction and inflammation. It may represent a response to local arterial hyperperfusion and hyperoxygenation resulting in oxidative stress. We aimed at obtaining closer insight into the pathogenesis of FNH with its characteristic morphologic features. Immunohistochemistry and immunofluorescence microscopy was performed on FNH specimens using antibodies against keratins (K) 7 and 19, neural cell adhesion molecule (NCAM), lamin B1, senescence markers (CDK inhibitor 1/p21Cip1, CDK inhibitor /p16Ink4a, senescence-associated (SA) ß- galactosidase activity), proliferation markers (Ki-67, proliferating-cell nuclear antigen (PCNA)), and the abnormally phosphorylated histone γ-H2AX, indicating DNA double strand breaks; moreover SA ß- galactosidase activity was determined histochemically. Ductular metaplasia of hepatocytes indicated by K7 expression in the absence of K19 plays a major role in the development of ductular reaction in FNH. Moreover, the expression of senescence markers (p21Cip1, p16Ink4a, γ-H2AX, SA ß-galactosidase activity) in hepatocytes and cholangiocytes suggests that stress-induced cellular senescence contributes to fibrosis and inflammation via production of components of the senescence-associated secretory phenotype. Expression of proliferation markers (Ki-67, PCNA) was not enhanced in hepatocytes and biliary cells. Senescence and ductular metaplasia of hepatocytes may thus be involved in inflammation, fibrosis and apoptosis resistance. Hence, fibrosis, inflammation and reduced apoptotic cell death, rather than proliferation (hyperplasia) may be responsible for increased tissue mass and tumour-like appearance of FNH.

Intrabodies against the Polysialyltransferases ST8SiaII and ST8SiaIV inhibit Polysialylation of NCAM in rhabdomyosarcoma tumor cells.

BACKGROUND: Polysialic acid (polySia) is a carbohydrate modification of the neural cell adhesion molecule (NCAM), which is implicated in neural differentiation and plays an important role in tumor development and metastasis. Polysialylation of NCAM is mediated by two Golgi-resident polysialyltransferases (polyST) ST8SiaII and ST8SiaIV. Intracellular antibodies (intrabodies; IB) expressed inside the ER and retaining proteins passing the ER such as cell surface receptors or secretory proteins provide an efficient means of protein knockdown. To inhibit the function of ST8SiaII and ST8SiaIV specific ER IBs were generated starting from two corresponding hybridoma clones. Both IBs αST8SiaII-IB and αST8SiaIV-IB were constructed in the scFv format and their functions characterized in vitro and in vivo. RESULTS: IBs directed against the polySTs prevented the translocation of the enzymes from the ER to the Golgi-apparatus. Co-immunoprecipitation of ST8SiaII and ST8SiaIV with the corresponding IBs confirmed the intracellular interaction with their cognate antigens. In CHO cells overexpressing ST8SiaII and ST8SiaIV, respectively, the transfection with αST8SiaII-IB or αST8SiaIV-IB inhibited significantly the cell surface expression of polysialylated NCAM. Furthermore stable expression of ST8SiaII-IB, ST8SiaIV-IB and luciferase in the rhabdomyosarcoma cell line TE671 reduced cell surface expression of polySia and delayed tumor growth if cells were xenografted into C57BL/6 J RAG-2 mice. CONCLUSION: Data obtained strongly indicate that αST8SiaII-IB and αST8SiaIV-IB are promising experimental tools to analyze the individual role of the two enzymes during brain development and during migration and proliferation of tumor cells.

Polyclonal neural cell adhesion molecule antibody prolongs the effective duration time of botulinum toxin in decreasing muscle strength.

This study aimed to investigate if the effective duration time of botulinum toxin A (Btx-A) could be prolonged by polyclonal neural cell adhesion molecule antibody (P-NCAM-Ab). 175 male SD rats were randomly divided into three major groups: control group (n = 25), Btx-A group (n = 25), and P-NCAM-Ab groups. P-NCAM-Ab groups were composed of five sub-groups, with 25 rats each in the dose-response study. Muscle strength of rat lower limbs was determined using a survey system. The expressions of muscle-specific receptor tyrosine kinase (MuSK) and neural cell adhesion molecule (NCAM) were determined by real-time polymerase chain reactions (RT-PCR) and western blotting (WB). The muscle strength was significantly decreased by Btx-A in Btx-A/P-NCAM-Ab groups compared with normal control group. Besides, the muscle strength of P-NCAM-Ab group was significantly decreased compared with the Btx-A group. The recovery time of muscle strength in P-NCAM-Ab group was significantly longer compared with Btx-A group. RT-PCR and WB assay showed that PNCAM-Ab delayed the increase of MuSK and NCAM after Btx-A injection. P-NCAM-Ab prolongs the effective duration time of Btx-A in decreasing muscle strength, which could provide a novel enhancement in clinical application.

Soluble polysialylated NCAM: a novel player of the innate immune system in the lung.

Posttranslational modification of the neural cell adhesion molecule (NCAM) by polysialic acid (polySia) is well studied in the nervous system and described as a dynamic modulator of plastic processes like precursor cell migration, axon fasciculation, and synaptic plasticity. Here, we describe a novel function of polysialylated NCAM (polySia-NCAM) in innate immunity of the lung. In mature lung tissue of healthy donors, polySia was exclusively attached to the transmembrane isoform NCAM-140 and located to intracellular compartments of epithelial cells. In patients with chronic obstructive pulmonary disease, however, increased polySia levels and processing of the NCAM carrier were observed. Processing of polysialylated NCAM was reproduced in a mouse model by bleomycin administration leading to an activation of the inflammasome and secretion of interleukin (IL)-1ß. As shown in a cell culture model, polySia-NCAM-140 was kept in the late trans-Golgi apparatus of lung epithelial cells and stimulation by IL-1ß or lipopolysaccharide induced metalloprotease-mediated ectodomain shedding, resulting in the secretion of soluble polySia-NCAM. Interestingly, polySia chains of secreted NCAM neutralized the cytotoxic activity of extracellular histones as well as DNA/histone-network-containing "neutrophil extracellular traps", which are formed during invasion of microorganisms. Thus, shedding of polySia-NCAM by lung epithelial cells may provide a host-protective mechanism to reduce tissue damage during inflammatory processes.

Nodal proteins are target antigens in Guillain-Barré syndrome.

Neurofascin-186 (NF186), neuronal cell adhesion molecule (NrCAM), and gliomedin are adhesion molecules playing a central role in the formation of nodes of Ranvier. In Guillain-Barré syndrome (GBS), immune attack toward the nodes may participate in the disabilities. Autoantibodies to NF186 and gliomedin have been detected in a rat model of GBS. Here, we investigated the prevalence of antibodies against nodal adhesion molecules in patients with GBS or chronic inflammatory demyelinating polyneuropathy (CIDP). Sera from 100 GBS patients, 50 CIDP patients, 80 disease controls, and 50 healthy controls were tested for their ability to bind the nodes of Ranvier. To characterize the antigens, we performed cell binding assays against NF186, gliomedin, contactin, and NrCAM. We found that 43% of patients with GBS and 30% of patients with CIDP showed IgG fixation at nodes or paranodes. In eight patients with GBS or CIDP, we identified that IgG antibodies recognized the native extracellular domain of NF186, gliomedin, or contactin. Also, 29 patients showed IgM against nodal adhesion molecules. However, we did not detect IgM fixation at nodes or paranodes. Antibodies to gliomedin or NF186 were mostly detected in demyelinating and axonal GBS, respectively. The adsorption of the antibodies to their soluble antigens abolished IgG deposition at nodes and paranodes in nerves, indicating these were specific to NF186, gliomedin, and contactin. In conclusion, gliomedin, NF186, and contactin are novel target antigens in GBS. At nodes, additional epitopes are also the targets of IgG. These results suggest that antibody attack against nodal antigens participates in the etiology of GBS.

NCAM-induced neurite outgrowth depends on binding of calmodulin to NCAM and on nuclear import of NCAM and fak fragments.

The neural cell adhesion molecule NCAM plays important functional roles not only during nervous system development, but also in the adult after injury and in synaptic plasticity. Homophilic binding of NCAM triggers intracellular signaling events resulting in cellular responses such as neurite outgrowth that require NCAM palmitoylation-dependent raft localization and activation of the nonreceptor tyrosine kinases fyn and fak. In this study, we show that stimulation of NCAM by a function-triggering NCAM antibody results in proteolytic processing of NCAM and fak. The C-terminal fragment of NCAM, consisting of the intracellular domain, the transmembrane domain, and a stub of the extracellular domain, and the N-terminal fragment of fak are imported into the nucleus. NCAM-stimulated fak activation, generation, and nuclear import of NCAM and fak fragments as well as neurite outgrowth are abolished by mutation of the calmodulin binding motif in the intracellular domain of NCAM that is responsible for the calcium-dependent binding of calmodulin to NCAM. This mutation interferes neither with NCAM cell surface expression, palmitoylation, and raft localization nor with fyn activation. The way by which the transmembrane NCAM fragment reaches the nucleus in a calmodulin- and calcium-dependent manner is by endocytotic transport via the endoplasmic reticulum and the cytoplasm. The generation and nuclear import of NCAM and phosphorylated fak fragments resulting from NCAM stimulation may represent a signal pathway activating cellular responses in parallel or in association with classical kinase- and phosphorylation-dependent signaling cascades.

Decidual CXCR4+ CD56bright NK cells as a novel NK subset in maternal-foetal immune tolerance to alleviate early pregnancy failure.

Natural killer (NK) cells preferentially accumulate at maternal-foetal interface and are believed to play vital immune-modulatory roles during early pregnancy and related immunological dysfunction may result in pregnant failure such as recurrent miscarriage (RM). However, the mechanisms underlying the establishment of maternal-foetal immunotolerance are complex but clarifying the roles of decidual NK (dNK) cells offers the potential to design immunotherapeutic strategies to assist RM patients. In this report, we analysed RNA sequencing on peripheral NK (pNK) and decidual NK cells during early pregnancy; we identified an immunomodulatory dNK subset CXCR4+ CD56bright dNK and investigated its origin and phenotypic and functional characteristics. CXCR4+ CD56bright dNK displayed a less activated and cytotoxic phenotype but an enhanced immunomodulatory potential relative to the CXCR4 negative subset. CXCR4+ CD56bright dNK promote Th2 shift in an IL-4-dependent manner and can be recruited from peripheral blood and reprogramed by trophoblasts, as an active participant in the establishment of immune-tolerance during early pregnancy. Diminished CXCR4+ dNK cells and their impaired ability to induce Th2 differentiation were found in RM patients and mouse models of spontaneous abortion. Moreover, adoptive transfer of CXCR4+ dNK cells to NK-deficient (Nfil3-/-) mice showed great therapeutic potential of CXCR4+ dNK via recovering the Th2/Th1 bias and reducing embryo resorption rates. The identification of this new dNK cell subset may lay the foundation for understanding NK cell mechanisms in early pregnancy and provide potential prognostic factors for the diagnosis and therapy of RM.

N-linked glycosylation is required for optimal function of Kaposi's sarcoma herpesvirus-encoded, but not cellular, interleukin 6.

Kaposi's sarcoma-associated herpesvirus interleukin-6 (vIL-6) is a structural and functional homologue of the human cytokine IL-6 (hIL-6). hIL-6 and vIL-6 exhibit similar biological functions and both act via the gp130 receptor subunit to activate the Janus tyrosine kinase (JAK)1 and signal transducer and activator of transcription (STAT)1/3 pathway. Here we show that vIL-6 is N-linked glycosylated at N78 and N89 and demonstrate that N-linked glycosylation at site N89 of vIL-6 markedly enhances binding to gp130, signaling through the JAK1-STAT1/3 pathway and functions in a cytokine-dependent cell proliferation bioassay. Although hIL-6 is also N-glycosylated at N73 and multiply O-glycosylated, neither N-linked nor O-linked glycosylation is necessary for IL-6 receptor alpha-dependent binding to gp130 or signaling through JAK1-STAT1/3. As distinct from vIL-6, unglycosylated hIL-6 is as potent as glycosylated hIL-6 in stimulating B cell proliferation. These findings highlight distinct functional roles of N-linked glycosylation in viral and cellular IL-6.

L1 antibodies block lymph node fibroblastic reticular matrix remodeling in vivo.

L1 is an immunoglobulin superfamily adhesion molecule highly expressed on neurons and involved in cell motility, neurite outgrowth, axon fasciculation, myelination, and synaptic plasticity. L1 is also expressed by nonneural cells, but its function outside of the nervous system has not been studied extensively. We find that administration of an L1 monoclonal antibody in vivo disrupts the normal remodeling of lymph node reticular matrix during an immune response. Ultrastructural examination reveals that reticular fibroblasts in mice treated with L1 monoclonal antibodies fail to spread and envelop collagen fibers with their cellular processes. The induced defect in the remodeling of the fibroblastic reticular system results in the loss of normal nodal architecture, collapsed cortical sinusoids, and macrophage accumulation in malformed sinuses. Surprisingly, such profound architectural abnormalities have no detectable effects on the primary immune response to protein antigens.

Polysialic acid, a glycan with highly restricted expression, is found on human and murine leukocytes and modulates immune responses.

Polysialic acid (polySia) is a large glycan with restricted expression, typically found attached to the protein scaffold neural cell adhesion molecule (NCAM). PolySia is best known for its proposed role in modulating neuronal development. Its presence and potential functions outside the nervous systems are essentially unexplored. Herein we show the expression of polySia on hematopoietic progenitor cells, and demonstrate a role for this glycan in immune response using both acute inflammatory and tumor models. Specifically, we found that human NK cells modulate expression of NCAM and the degree of polymerization of its polySia glycans according to activation state. This contrasts with the mouse, where polySia and NCAM expression are restricted to multipotent hematopoietic progenitors and cells developing along a myeloid lineage. Sialyltransferase 8Sia IV(-/-) mice, which lacked polySia expression in the immune compartment, demonstrated an increased contact hypersensitivity response and decreased control of tumor growth as compared with wild-type animals. This is the first demonstration of polySia expression and regulation on myeloid cells, and the results in animal models suggest a role for polySia in immune regulation.

A yeast display immunoprecipitation method for efficient isolation and characterization of antigens.

Yeast antibody display has found a wide variety of applications including antibody affinity maturation, epitope mapping, and library screening. Here we report a yeast display immunoprecipitation (YDIP) technique that employs yeast cells displaying single-chain antibody fragments (scFv) on their surface as affinity capture reagents to isolate and characterize antigens. We show that displayed single-chain antibody fragments are active in a variety of detergent solutions commonly used for immunoprecipitation and that the antigen-antibody interaction can be accurately quantified by YDIP coupled with flow cytometry. The YDIP method has also been optimized so that it is compatible with commonly used protein characterization tools such as Western blotting, silver staining, and mass spectrometry. From complex protein mixtures, we have used YDIP to isolate, analyze and sequence both soluble and plasma membrane antigens using tandem mass spectrometry. In the case of the membrane antigen, YDIP coupled with tandem mass spectrometry was successful in identifying neural cell adhesion molecule (NCAM) as the antigen for an antibody previously selected as binding to the plasma membranes of brain endothelial cells. The presented method therefore has potential to facilitate antibody-antigen characterization.

New multiple labelling method for improved satellite cell identification in human muscle: application to a cohort of power-lifters and sedentary men.

Presently applied methods to identify and quantify human satellite cells (SCs) give discrepant results. We introduce a new immunofluorescence method that simultaneously monitors two SC markers (NCAM and Pax7), the basal lamina and nuclei. Biopsies from power-lifters, power-lifters using anabolic substances and untrained subjects were re-examined. Significantly different results from those with staining for NCAM and nuclei were observed. There were three subtypes of SCs; NCAM(+)/Pax7(+) (94%), NCAM(+)/Pax7(-) (4%) and NCAM(-)/Pax7(+) (1%) but large individual variability existed. The proportion of SCs per nuclei within the basal lamina of myofibres (SC/N) was similar for all groups reflecting a balance between the number of SCs and myonuclei to maintain homeostasis. We emphasise that it is important to quantify both SC/N and the number of SCs per fibre. Our multiple marker method is more reliable for SC identification and quantification and can be used to evaluate other markers of muscle progenitor cells.

Role of CD47 as a marker of self on red blood cells.

The immune system recognizes invaders as foreign because they express determinants that are absent on host cells or because they lack "markers of self" that are normally present. Here we show that CD47 (integrin-associated protein) functions as a marker of self on murine red blood cells. Red blood cells that lacked CD47 were rapidly cleared from the bloodstream by splenic red pulp macrophages. CD47 on normal red blood cells prevented this elimination by binding to the inhibitory receptor signal regulatory protein alpha (SIRPalpha). Thus, macrophages may use a number of nonspecific activating receptors and rely on the presence or absence of CD47 to distinguish self from foreign. CD47-SIRPalpha may represent a potential pathway for the control of hemolytic anemia.

Polysialic acid masks neural cell adhesion molecule antigenicity.

The neural cell adhesion molecule (NCAM) is a transmembrane protein involved in major cellular processes. The addition of polysialic acid (PSA), a post-translational modification (PTM) almost exclusively carried by NCAM, alters NCAM properties and functions and is therefore tightly regulated. Changes in NCAM and PSA-NCAM take place during development and ageing and occur in various diseases. The presence of PTMs can reduce the accessibility of antibodies to their epitopes and lead to false negative results. Thus, it is vital to identify antibodies that can specifically detect their target regardless of the presence of PTMs. In the present study, four commercially available NCAM antibodies were characterized by western blot and immunocytochemistry. Antibody specificity was determined by decreasing NCAM expression with small interfering RNA and subsequently determining whether the antibodies still produced a signal. In addition, PSA was digested with endoneuraminidase N to assess whether removing PSA improves NCAM detection with these antibodies. Our study revealed that the presence of PSA on NCAM reduced antibody accessibility to the epitope and consequently masked NCAM antigenicity for both techniques investigated. Moreover, three of the four antibodies tested were specific for the detection of NCAM by western blot and by immunocytochemistry. Altogether, this study demonstrates the importance of choosing the correct antibody to study NCAM depending on the technique of interest and underlines the importance of taking PTMs into account when using antibody-based techniques for the study of NCAM.

Involvement of NCAM in the effects of GDNF on the neurite outgrowth in the dopamine neurons.

Glial cell line-derived neurotrophic factor (GDNF) exerts its biological effects via a multi-component receptor system including the ligand binding receptor--GDNF family receptor-alpha1 (GFRalpha1) and the signaling receptor--RET tyrosine kinase. Recently, the neural cell adhesion molecule (NCAM) has been identified as an alternative signaling receptor for GDNF. The purpose of this study was to investigate whether NCAM could mediate the protective effect of GDNF on injured dopamine (DA) neurons and to determine which cytoplasmic signal molecule associated with NCAM was activated while GDNF performing this effect. The results showed that the phosphorylation of NCAM-associated Fyn was upregulated with GDNF treatment, and this upregulation was inhibited by pre-treatment with the NCAM function-blocking antibody. Moreover, pre-treatment with the antibody could abolish the effect of GDNF on promoting the neurite outgrowth of these DA neurons, except for the effect of GDNF on promoting the expression of tyrosine hydroxylase (TH) in these DA neurons. These results suggest that NCAM is involved in the promotive effect of GDNF on the neurite outgrowth in lesioned DA neurons, but not involved in the promotive effect of GDNF on TH expression in these neurons.

Long-term potentiation in mice lacking the neural cell adhesion molecule L1.

Genetic evidence indicates that cell adhesion molecules of the immunoglobulin superfamily (IgCAMs) are critical for activity-dependent synapse formation at the neuromuscular junction in Drosophila and have also been implicated in synaptic remodelling during learning in Aplysia (see [1] for review). In mammals, a widely adopted model for the process of learning at the cellular level is long-term potentiation (LTP) in the hippocampal formation. Studies in vitro have shown that antibodies to the IgCAMs L1 and NCAM reduce LTP in CA1 neurons of rat hippocampus, suggesting a role for these molecules in the modulation of synaptic efficacy, perhaps by regulating synaptic remodelling [2]. A role for NCAM in LTP has been confirmed in mice lacking NCAM [3] (but see [4]), but similar studies have not been reported for L1. Here we examine LTP in the hippocampus of mice lacking L1 [5,6], using different experimental protocols in three different laboratories. In tests of LTP in vitro and in vivo we found no significant differences between mutant animals and controls. Thus, contrary to expectation, our data suggest that L1 function is not necessary for the establishment or maintenance of LTP in the hippocampus. Impaired performance in spatial learning exhibited by L1 mutants may therefore not be due to hippocampal dysfunction [6].

Targeting the neural cell adhesion molecule in cancer.

NCAM is a tumour associated antigen expressed on small cell lung cancer, neuroblastoma, rhabdomyosarkoma, brain tumours, multiple myelomas and acute myeloid leukaemia. Constant and strong expression of NCAM is a prerequisite for the development of antibody-based immunotherapies. From the spectrum of existing anti-NCAM compounds, radioimmunoconjugates and immunotoxins represent the clinically most advanced and successful strategies. Here we provide an overview of the evolving field of anti-NCAM immunotherapy for cancer and discuss its indications and limitations.

The characteristics of hematopoietic stem cells from autoimmune-prone mice and the role of neural cell adhesion molecules in abnormal proliferation of these cells in MRL/lpr mice.

BACKGROUND AND OBJECTIVES: Using various animal models for autoimmune diseases, we have previously shown that such diseases are stem cell disorders.1 In order to understand how autoimmune diseases develop, we investigated the distinct qualitative differences between hematopoietic stem cells (HSC) from normal and autoimmune-prone mice. DESIGN AND METHODS: We studied the major histocompatibility complex (MHC) restriction between HSC and stromal cells in vitro and in vivo. We also examined the ability of HSC to adhere to a stromal cell line and, using flow cytometry, analyzed the expression of various adhesion molecules in HSC before and after the onset of autoimmune disease. In addition, the effect of antibodies to anti-adhesion molecules on the proliferation of HSC was investigated. RESULTS: The abnormal HSC of MRL/lpr mice showed no MHC restriction (or preference) with stromal cells either in vitro or in vivo, although there was MHC restriction between normal HSC and stromal cells, as we previously reported.2,3 The abnormal HSC of MRL/lpr mice exhibited enhanced adhesion to stromal cells in vitro and expressed a higher amount of adhesion molecules such as neural cell adhesion molecule (NCAM). Interestingly, the proliferation of HSC in MRL/lpr mice was significantly suppressed by anti-NCAM monoclonaal antibodies. INTERPRETATION AND CONCLUSIONS: Abnormal HSC of MRL/lpr mice are more resilient than normal HSC. Furthermore, among various adhesion molecules, only NCAM shows increased expression on HSC of MRL/lpr mice after the onset of autoimmune diseases, and these molecules contribute to the enhanced proliferation capacity of abnormal HSC in MRL/lpr mice. The present findings suggest that there are intrinsic qualitative differences between HSC from normal and autoimmune-prone MRL/lpr mice.

Generation and intracellular trafficking of a polysialic acid-carrying fragment of the neural cell adhesion molecule NCAM to the cell nucleus.

Polysialic acid (PSA) and its major protein carrier, the neural cell adhesion molecule NCAM, play important roles in many nervous system functions during development and in adulthood. Here, we show that a PSA-carrying NCAM fragment is generated at the plasma membrane by matrix metalloproteases and transferred to the cell nucleus via endosomes and the cytoplasm. Generation and nuclear import of this fragment in cultured cerebellar neurons is induced by a function-triggering NCAM antibody and a peptide comprising the effector domain (ED) of myristoylated alanine-rich C kinase substrate (MARCKS) which interacts with PSA within the plane of the plasma membrane. These treatments lead to activation of the fibroblast growth factor (FGF) receptor, phospholipase C (PLC), protein kinase C (PKC) and phosphoinositide-3-kinase (PI3K), and subsequently to phosphorylation of MARCKS. Moreover, the NCAM antibody triggers calmodulin-dependent activation of nitric oxide synthase, nitric oxide (NO) production, NO-dependent S-nitrosylation of matrix metalloprotease 9 (MMP9) as well as activation of matrix metalloprotease 2 (MMP2) and MMP9, whereas the ED peptide activates phospholipase D (PLD) and MMP2, but not MMP9. These results indicate that the nuclear PSA-carrying NCAM fragment is generated by distinct and functionally defined signal transducing mechanisms.

The neural cell adhesion molecule antibody blocks cold water swim stress-induced analgesia and cell adhesion between lymphocytes and cultured dorsal root ganglion neurons.

BACKGROUND: Opioid-containing immune cells migrate in a site-directed manner into inflamed tissue and adhere to sensory nerve fibers. These cells release opioid peptides in close proximity to these fibers, thereby avoiding localized degradation by peptidases, and delivering opioid peptides proximal to opioid receptors to provide antinociception. METHODS: The effects of the anti-neural-cell-adhesion molecule (anti-NCAM) were assessed on cold water swim stress-induced antinociception in Wistar rats with Freund's adjuvant-induced inflammation of one hindpaw. Algesiometry was assessed for both thermal and mechanical stimuli. Cell adhesion experiments examining the effects of beta-endorphin and antibodies to NCAM and intercellular cell adhesion molecule-1 and were performed on cultured dorsal root ganglion neurons and isolated lymphocytes. Lymphocyte binding was determined by fluorescence using calcein AM loaded into freshly isolated lymphocytes. RESULTS: The direct adhesion between lymphocytes and cultured sensory neurons was inhibited by anti-NCAM. This adhesion was also demonstrated to be opioid dependent, with lymphocyte adhesion to cultured sensory neurons reduced in the presence of 1 microM beta-endorphin, which was reversed by 100 microM naloxone. Moreover, anti-NCAM blocked cold-water-swim-induced analgesia in inflamed paws both to thermal and mechanical stimuli. However, anti-NCAM did not affect fentanyl-induced antinociception. CONCLUSIONS: This study provides insight into the role of cell adhesion molecules in lymphocyte adhesion to sensory neurons and a link to immune-derived antinociception.