The binding of fucose-containing glycoproteins by hepatic lectins. Re-examination of the clearance from blood and the binding to membrane receptors and pure lectins

The nature of the hepatic receptors that bind glycoproteins through fucose at the non-reducing termini of oligosaccharides in glycoproteins has been examined by three different approaches. First, the clearance from blood of intravenously injected glycoproteins was examined in mice with the aid of neoglycoproteins of bovine serum albumin (BSA). The clearance of fucosyl-BSA was rapid and was not strongly inhibited by glycoproteins that inhibit clearance mediated by the galactose or the mannose/N-acetylglucosamine receptors of liver. The clearance of Fuc alpha 1,3(Gal beta 1,4)GlcNAc-BSA (where Fuc is fucose) was inhibited weakly by either Fuc-BSA or Gal beta 1,4GlcNAc-BSA but strongly by a mixture of the two neoglycoproteins, suggesting that its clearance was mediated by hepatic galactose receptors as well as by a fucose-binding receptor. Second, the binding of neoglycoproteins to a membrane fraction of mouse liver was examined. Fuc-BSA binding to membranes was Ca2+ dependent but was not inhibited by glycoproteins that would inhibit the galactose or the mannose/N-acetylglucosamine receptors. In addition, the binding of Fuc-BSA and Gal beta 1,4GlcNAc-BSA differed as a function of pH, in accord with binding of Fuc-BSA through fucose-specific hepatic receptors. Finally, the binding of neoglycoproteins to the pure galactose lectin from rat liver was examined. Neither Fuc-BSA nor Fuc alpha 1,2Gal beta 1,4GlcNAc-BSA bound the galactose lectin, although Fuc alpha 1,3(Gal beta-1,4) GlcNAc-BSA bound avidly. Taken together, these studies suggest that a fucose-binding receptor that differs from the galactose and the mannose/N-acetylglucosamine receptors may exist in rat and mouse liver.     

Sites of action of soltriol (vitamin D) in hamster spleen,thymus, and lymph node,studied by autoradiography

Summary Sibirian hamsters (Photopus sungorus) were injected with³H dihydroxycholecalciferol (vitamin D, soltriol). Autoradiograms of spleen, thymus, and lymph nodes revealed nuclear concentration of the hormone in a select population of cells in all of these organs. In the spleen, labeled cells were abundant in the red pulp, but sparse in the white pulp. In the periarterial lymphatic sheath (PALS) labeled cells were found predominatly at the outer rim, with a few scattered labeled cells in the inner PALS and in the marginal zone. Lymphocytes, including pyronin-positive plasma cells, did not display nuclear labeling. In the red pulp, some of the labeled cells contained pigmented inclusions in the cytoplsm, while most of the labeled cells did not appear phagocytic under the conditions of the experiment. In the thymus, labeled cells were most numerous in the medulla, but sparse in the cortex. Many of the thymic target cells were larger than the unlabeled lymphocytes, with a large and pale nucleus, sometimes containing a distinct nucleolus, and with large and dendritic cytoplasm, having the appearance and distribution of epithelio-reticular cells. In lymph nodes, scattered labeled cells were conspicuous in or near the subcapsular sinus, while other cells did not concentrate radioactivity in their nuclei. The results indicate that nuclear receptors and direct genomic actions for soltriol exist in certain cell populations of lymphatic tissues that probably include reticular cells and a subpopulation of macrophages. These target cells may mediate effects of the steroid on lymphocytes that appear to have no or only very low numbers of nuclear receptors.     

Mannose-specific binding sites for horseradish peroxidase in various cells of the rat

Mannose-specific binding sites for horseradish peroxidase (HRP) were studied in fixed sections of various tissues by a method reported previously. Liver sinusoidal cells, mast cells of lymph nodes, and alveolar macrophages of the lung and skin fibroblasts were main cell types showing mannose-specific binding of HRP. Macrophages, fibroblasts, and mast cells in the connective tissue of other organs also showed the reaction. However, macrophages of the spleen, and cultured 3T3 cells and L-cells did not give the reaction. The specificities of the binding reaction were studied by determining the approximate concentrations of competing sugars that suppressed the specific binding of HRP. It was found that the endogenous lectins in macrophages, fibroblasts, mast cells, and liver sinusoidal cells showed similar specificities toward various carbohydrates. D-Mannose and L-fucose had the highest affinity toward the lectins (competing ability for the binding of HRP). D-Mannose-6-phosphate, N-acetyl-D-glucosamine, D-glucose, D-ribose, and D-arabinose showed intermediate affinity, whereas D-xylose and D-galactose showed low affinity. Polymerized mannose in mannan and glycoproteins rich in mannose groups (invertase and ribonuclease B) showed much higher affinity to the binding sites than free mannose.     

Migration patterns of dendritic cells in the rat: comparison of the effects of gamma and UV-B irradiation on the migration of dendritic cells and Lymphocytes

To further define the underlying mechanisms of immune suppression induced by UV-B irradiation, we have examined the kinetics of homing patterns of in vitro UV-B-irradiated and gamma-irradiated-thoracic duct lymphocytes (TDL) compared to dendritic cells (DC). Our findings show that 111In-oxine-labeled TDL specifically home to the spleen, liver, lymph nodes, and bone marrow with subsequent recirculation of a large number of cells from the spleen to lymph nodes. In contrast, DC preferentially migrate to the spleen and liver with a relatively insignificant distribution to lymph nodes and an absence of subsequent recirculation. Splenectomy prior to cell injection significantly diverts the spleen-seeking DC to the liver but not to the lymph nodes, while the homing of TDL to lymph nodes is significantly increased. In vitro exposure of 111In-oxine labeled TDL to gamma irradiation does not significantly impair immediate homing to lymphoid tissues but inhibits cell recirculation between 3 and 24 hr. In contrast, gamma irradiation does not affect the tissue distribution of labeled DC, suggesting that DC are more radioresistant to gamma irradiation than TDL. Unlike the findings in animals injected with gamma-irradiated cells, UV-B irradiation virtually abolished the homing of TDL to lymph nodes and significantly reduced the homing of the spleen-seeking DC to the splenic compartment while a large number of cells were sequestered in the liver. The results of in vitro cell binding assay show that TDL, unlike DC, have the capacity to bind to high endothelial venules (HEV) within lymph node frozen sections while gamma and UV-B irradiation significantly inhibit the binding of TDL to lymph node HEV. These findings suggest that: (i) DC, unlike TDL, are unable to recirculate from blood to lymph nodes through HEV; (ii) although gamma irradiation impairs TDL recirculation, it does not affect DC tissue distribution; and (iii) UV-B irradiation impairs both TDL and DC migration patterns. We conclude that the lack of capacity of irradiated TDL to home to lymph nodes is due to damage to cell surface homing receptors and that the failure of DC to home to the lymph node microenvironment is related to the absence of HEV homing receptors on their cell surface.     

Localization of surfactant protein A (SP-A) in alveolar macrophage subpopulations of normal and fibrotic rat lung

The colocalization of surfactant protein A (SP-A) and the alveolar macrophage markers ED1 and RM-1, as well as various lectins of the N-acetyl-galactosamine group [Maclura pomifera lectin (MPA), Dolichos biflorus lectin (DBA), soybean agglutinin (SBA)] and of the mannose group [Canavalia ensiformis lectin (ConA), Galanthus nivalis lectin (GNA)] was studied in normal and fibrotic rat lung tissues. In normal tissue, SP-A was located preferentially in the alveolar macrophage subpopulation lacking specific binding sites for lectins of the N-acetylgalactosamine group (DBA and SBA), although 50% of MPA-binding macrophages contained SP-A. The ED1-positive cells were SP-A-negative, whereas SP-A uptake could be detected among the RM-1 immunoreactive as well as the ConA and GNA binding macrophages. In fibrotic lung tissue, however, a small number of .DBA and SBA binding macrophages contained SP-A and the percentage of GNA and ConA binding alveolar macrophages exhibiting SP-A immunoreactivity was reduced. Additionally, the number of ED1⁺/SP-A⁺ macrophages was found to be increased. Immunoelectron microscopy revealed accumulation of SP-A in the extracellular space. The differing SP-A content in different alveolar macrophage subpopulations suggests a more complex mechanism of uptake and degradation of surfactant proteins in normal and pathological conditions, which cannot simply be explained by the glycoconjugate pattern on the surface of alveolar macrophages.     

The role of extra-hepatic tissues in the receptor-mediated plasma clearance of glycoproteins terminated by mannose or N-acetylglucosamine.

The mannose- and N-acetylglucosamine-specific pathway for the clearance of mammalian glycoproteins has been characterized by using 125I-labelled neoglycoproteins, glycosidase-treated orosomucoid and lysosomal glycosidases (beta-glucuronidase and beta-N-acetylglucosaminidase) as probes. There are two components to this pathway in vivo; one liver-dependent and the other extrahepatic or liver-independent. Cells that mediate clearance by the latter component of the pathway are present in spleen, bone and in elements of the reticuloendothelial system, but not in the kidney. Glycoproteins that possess terminal mannose, glucose or N-acetylglucosamine residues, including various lysosomal enzymes, are rapidly cleared from plasma via this pathway. Glucose-terminated glycoproteins are recognized by two pathways in the intact animal; the hepatic galactose-specific pathway and the mannose/N-acetylglycosamine-specific pathway, which is present in liver and in peripheral tissues. Following removal of the liver by surgical evisceration, glucose-terminated glycoproteins are cleared whereas glycoproteins bearing galactose are not cleared. Uptake of 125I-labelled neoglycoproteins and agalacto-orosomucoid by isolated alveolar macrophages closely mimics clearance in vivo by the mannose/N-acetylglucosamine pathway. Neoglycoproteins terminated by mannose, glucose or N-acetylglucosamine all compete with 125I-labelled agalacto-orosomucoid for uptake by receptor-mediated pinocytosis. The extent of substitution of the neoglycoproteins is a critical determinant of their inhibitory potency. It is proposed that mononuclear phagocytes are in important component of the clearance pathway in vivo. The mannose/N-acetylglucosamine pathway may be important in the regulation of extracellular levels of various glycosylated macromolecules, including lysosomal hydrolases.     

Cell-specific glycoforms of sialoadhesin and CD45 are counter-receptors for the cysteine-rich domain of the mannose receptor

We previously reported that CR-Fc, an Fc chimeric protein containing the cysteine-rich (CR) domain of the mannose receptor, binds to marginal zone metallophilic macrophages (Mo) and B cell areas in the spleen and to subcapsular sinus Mo in lymph nodes of naive mice (CR-Fc(+) cells). Several CR-Fc ligands were found in spleen and lymph node tissue lysates using ligand blots. In this paper we report the identification of two of these ligands as sialoadhesin (Sn), an Mo-specific membrane molecule, and the leukocyte common antigen, CD45. CR-Fc bound selectively to Sn purified from spleen and lymph nodes and to two low molecular weight isoforms of CD45 in a sugar-dependent manner. CR-Fc binding and non-binding forms of Sn, probably derived from CR-Fc(+) and CR-Fc(-) cells respectively, were selected from spleen lysates. Analysis of the glycan pool associated with the CR-Fc-binding form revealed the presence of charged structures resistant to sialidase, absent in the non-binding form, that could correspond to sulfated structures. These results confirm the identification of the CR region of the mannose receptor as a lectin. We also demonstrate that the same glycoprotein expressed in different cells of the same organ can display distinct sugar epitopes that determine its binding properties.     

Lymph node macrophages, but not spleen macrophages, express high levels of unmasked sialoadhesin: implication for the adhesive properties of macrophages in vivo

Sialoadhesin is a macrophage-restricted adhesion molecule that recognizes N-acetylneuraminylalpha2-3galactose structure. We prepared a multivalent neoglycoprotein probe carrying this oligosaccharide and characterized the binding activity of sialoadhesin on native rat macrophages. Macrophages from mesenteric and axillar lymph nodes exhibited 36-fold higher activity than those from the spleen. The K(d) values of the probe binding to macrophages of the two organs were indistinguishable (1-2 nM), whereas the B(max) value of lymph node macrophages was markedly higher than that of splenic macrophages. Western blot analysis revealed that the quantity of sialoadhesin present in lymph node macrophages was 25-fold higher than in splenic macrophages. High cell surface expression of sialoadhesin on lymph node macrophages was also shown by flow cytometry. To examine the "masking" of sialoadhesin by endogenous sialoglycoconjugates, we treated macrophages with sialidase before measuring the probe binding. After sialidase treatment, the binding activity of splenic macrophages increased fourfold, whereas that of lymph node macrophages did not increase. In conclusion, we have identified macrophages expressing high levels of unmasked sialoadhesin in lymph nodes. The unmasked forms on these macrophages are available for sialoadhesin-dependent adhesive functions, unlike the masked forms on the majority of splenic macrophages.     

Sites of action of soltriol (vitamin D) in hamster spleen, thymus, and lymph node, studied by autoradiography

Siberian hamsters (Photopus sungorus) were injected with 3H dihydroxycholecalciferol (vitamin D, soltriol). Autoradiograms of spleen, thymus, and lymph nodes revealed nuclear concentration of the hormone in a select population of cells in all of these organs. In the spleen, labeled cells were abundant in the red pulp, but sparse in the white pulp. In the periarterial lymphatic sheath (PALS) labeled cells were found predominantly at the outer rim, with a few scattered labeled cells in the inner PALS and in the marginal zone. Lymphocytes, including pyronin-positive plasma cells, did not display nuclear labeling. In the red pulp, some of the labeled cells contained pigmented inclusions in the cytoplasm, while most of the labeled cells did not appear phagocytic under the conditions of the experiment. In the thymus, labeled cells were most numerous in the medulla, but sparse in the cortex. Many of the thymic target cells were larger than the unlabeled lymphocytes, with a large and pale nucleus, sometimes containing a distinct nucleous, and with large and dendritic cytoplasm, having the appearance and distribution of epithelio-reticular cells. In lymph nodes, scattered labeled cells were conspicuous in or near the subcapsular sinus, while other cells did not concentrate radioactivity in their nuclei. The results indicate that nuclear receptors and direct genomic actions for soltriol exist in certain cell populations of lymphatic tissues that probably include reticular cells and a subpopulation of macrophages. These target cells may mediate effects of the steroid on lymphocytes that appear to have no or only very low numbers of nuclear receptors.     

Membrane lectins on human monocytes. Maturation-dependent modulation of 6-phosphomannose and mannose receptors

Freshly isolated human monocytes, which do not contain cell-surface mannose-specific receptors, bind mannose 6-phosphate and actively endocytose mannose 6-phosphate-bearing neoglycoproteins (6-P-Man-F-BSA). Three days after isolation, human monocytes endocytose very actively 6-P-Man-F-BSA as well as Man-F-BSA, and the endocytosed neoglycoproteins are rapidly degraded. These results were obtained in quantitative flow cytofluorometry by using a panel of fluoresceinylated sugar-substituted serum albumins (neoglycoproteins). Thus, in contrast to mannose receptors which appear only after maturation, mannose 6-phosphate receptors are already present on freshly isolated human monocytes.     

Early postnatal development of the immune system in piglets: the redistribution of T lymphocyte subsets

In this study, we have characterised postnatal changes in T lymphocyte subsets, especially γδ T lymphocytes, in blood, spleen and lymph nodes. Detection was carried out using two-colour flow cytometry and three-colour immunohistochemistry. During ontogeny, there was a significant increase in the total percentage of γδ T cells in the spleen and blood. In the lymph nodes, there were no age-dependent changes in the total percentage of γδ T cells, but the percentage of the γδTCR⁺CD8⁺ subpopulation significantly increased. The tissue distribution of γδTCR⁺CD8⁺ and γδTCR⁺CD8⁻ cells in the lymph nodes is random and not collocated with a particular area of the organ. Furthermore, postnatal development was characterised by an increasing frequency of CD8⁺CD3⁺CD4⁻γδTCR⁻, which was compensated by a decreasing proportion of CD4⁺ lymphocytes. Double positive CD4⁺CD8⁺ lymphocytes were rare during the first month of life and a significant age-dependent increase of these cells was found in all the compartments monitored.     

Localization of PNA-binding and nonbinding thymus cells in peripheral lymphoid organs

Thymus cells were labeled in vitro with FITC and injected into syngeneic recipients. In cell suspensions of lymphoid organs green cells were inspected for PNA receptors with double immunofluorescence. A striking preference of PNA-negative cells to localize in lymph nodes and the lymphoid compartment of the spleen was demonstrated. Incubation with anti-Ly sera revealed that Ly 1⁺ PNA-negative cells homed in popliteal lymph nodes and Peyer's patch but not in mesenteric lymph nodes.     

Distribution of murine mannose receptor expression from early embryogenesis through to adulthood

The mannose receptor is a 175-kDa transmembrane glycoprotein that appears to be expressed on the surface of terminally differentiated macrophages and Langerhans cells. The ectodomain of the mannose receptor has eight carbohydrate recognition domains. The receptor recognizes the patterns of sugars that adorn a wide array of bacteria, parasites, yeast, fungi, and mannosylated ligands. Clearance studies in whole animals have localized radiolabeled ligands, such as mannosylated bovine serum albumen, not only to macrophages, but also to liver sinusoidal endothelial cells. Hitherto, there has been no comprehensive analysis of expression of the mannose receptor in embryonic and adult mouse tissues. In this study, we have undertaken a systematic survey of the expression of the mannose receptor from early embryogenesis through to adulthood. The mannose receptor is expressed on tissue macrophages throughout the adult mouse as expected. However, the mannose receptor is first observed on embryonic day 9 on cells that line blood island vessel walls in the yolk sac. The mannose receptor is localized on sinusoidal endothelial cells in embryonic liver by embryonic day 11 and in bone marrow at embryonic day 17. This pattern persists in these organs throughout embryogenesis into adulthood when sinusoidal endothelial cells of lymph nodes also express the mannose receptor. The receptor is also found on lymphatic endothelial cells of small intestine. In contrast, sinusoids of spleen and thymus do not express mannose receptor antigen. This study demonstrates that the mannose receptor is expressed on tissue macrophages and on subsets of vascular and lymphatic endothelial cells. Thus, the mannose receptor maybe a marker of the so-called reticuloendothelial system.     

Macrophage depletion in the rat after intraperitoneal administration of liposome-encapsulated clodronate: Depletion kinetics and accelerated repopulation of peritoneal and omental macrophages by administration of freund's adjuvant

The purpose of this study was to develop a method for the depletion of macrophages from the peritoneal cavity and the omentum of the rat. Rats received two intraperitoneal injections (at days 0 and 3) with liposome-encapsulated clodronate (dichloromethylene bisphosphonate: Cl₂MBP-liposomes). This treatment resulted in complete elimination of mature tissue macrophages (ED2-positive macrophages) from the peritoneal cavity and the omentum within 2 days. The elimination included the strongly ED2-positive spindle-shaped cells of the omental membrane. Repopulation of the omental ED2-positive macrophages was not seen within the next 23 days. Whereas ED2-positive macrophages were completely depleted, few ED1-positive cells remained and repopulation of ED1-positive cells was faster. The treatment further depleted macrophages from the spleen, especially from the red pulp, parathymic lymph nodes and liver. Freund's incomplete adjuvant administered one day after the last injection of Cl₂MBP-liposomes considerably accelerated repopulation in the omentum. The protocol described might be used to investigate the contribution of mature tissue macrophages to the induction of immune responses, drug metabolism and the elimination of intestinal tumours.     

Changes in homing receptor expression on murine lymphokine-activated killer cells during IL-2 exposure

The effects of IL-2 on the expression of homing receptors by lymphocytes of NK or lymphokine activated killer (LAK) cell derivation has not yet been evaluated. We developed a murine model to evaluate the potential of LAK cells to localize into peripheral lymph nodes since LAK cells are used to treat human cancers which have metastasized to these tissues. Using a frozen section binding assay, LAK cell adhesion to the lymph node microvasculature was easily demonstrable. Inhibition studies demonstrated that LAK cell binding to lymph nodes was mediated by mechanisms previously described in T cells. LAK cell surface expression of the 85- to 95-kDa homing receptor recognized by the antibody MEL-14 on LAK cells was assessed by indirect immunofluorescence. The percentage of cells which bound MEL-14 decreased slightly over 3 days of IL-2 exposure (from 73 to 60%), particularly in the large granular lymphocyte (cytotoxic effector) subpopulation (45% MEL-14+). The expression of another homing-related molecule, leukocyte function-associated Ag-1, markedly increased during activation of LAK cells. Despite the expression of these homing receptors, we observed almost no LAK cell localization into lymph nodes in vivo. Furthermore, IL-2 pretreatment of recipient animals did not increase the adhesion of LAK cells to lymph node microvasculature or enhance their extravasation. IL-2 activation of non-T, non-B lymphocytes results in significant changes in both the expression and function of cell surface homing receptors. Our results indicate that in vitro analysis does not always predict in vivo localization potential.     

GFP transgenic mice show dynamics of lung macrophages

The dynamics of tissue macrophages are poorly understood. We have developed a model where only lung macrophages express high levels of enhanced green fluorescent protein (EGFP) and are easily identified and followed by confocal microscopy. The EGFP⁺ cells had the morphology of macrophages and express CD11c, CD11b, and F4/80, but not NK1.1 or CD3. The F4/80⁺EGFP⁺ cells were found exclusively in the lung and not in lymph nodes, spleen, blood, liver, intestine, or uterus. These EGFP⁺ cells are phagocytic and can be activated to migrate within the lung in response to LPS stimulation. In this study, we describe a new model system that allows the specific study of macrophages in the lung.     

Eradication of metastatic tumour cells from lymph nodes by local administration of anti-CD3 antibody

The possibility of in vivo removal of metastatic tumour cells from lymph nodes by local intradermal administration of an anti-CD3 monoclonal antibody (mAb) was examined. Murine tumour cells in the lymph nodes were completely eradicated by intradermal injections of the mAb. This treatment was effective for removal of Lewis lung cancer cells from lymph nodes, but not for removal of subcutaneous tumours of this cell line. This treatment induced in vivo cytotoxicity in the regional lymph nodes against the syngeneic tumour cells. The following in vitro studies suggested that the cytotoxicity was probably mediated mainly by CD4⁺ T cells, with slight participation of CD8⁺ T cells. Normal lymph node and spleen cells showed cytotoxicity after in vitro incubation with the mAb for 2 days. Cell sorting with a fluoresceinactivated cell sorter showed that CD4⁺ T cells developed during the incubation to lyse syngeneic tumor cells directly by themselves, macrophages not being involved in this tumour cell lysis. The lytic activity was detected in the cellular fractions, but not in the culture supernatants of these T cells. Furthermore, it was completely blocked by specific antiserum for tumour necrosis factor- (TNF). An immunoprecipitation study revealed that these T cells expressed TNF molecules of 26 kDa, but not of 17 kDa, suggesting that tumour cell lysis was caused by membraneintegrated TNF molecules. These results strongly suggest that local administration of anti-CD3 antibody is a very effective and appropriate procedure for eradication of metastatic tumour cells from regional lymph nodes.     

A monoclonal antibody raised against Alzheimer cortex that specifically recognizes a subpopulation of microglial cells

A monoclonal antibody (MAb), termed AMC30, was raised after in vitro immunization with sonicated neurofibrillary tangle (NFT)-enriched fractions prepared from Alzheimer's brain. The antigen to which AMC30 is directed was expressed by microglial cells in senile plaques of Alzheimer's disease (AD). Microglia in the parenchyma surrounding brain tumors or infarctions, multinuclear giant cells, perivascular and parenchymal macrophages throughout the brain of AIDS patients were also labeled. Different non-nervous system lesions in which macrophages participate were also stained. Microglial cells in normal areas of the cortex or white matter were not labeled with MAb AMC30. The antigen to which AMC30 is directed was not detected in normal bone marrow, lymph nodes, lung, or spleen monocytes or macrophages. The epitope recognized by MAb AMC30 was present after formalin fixation and paraffin embedding. Our findings suggest that this MAb is directed against an antigen that is specifically expressed in a subpopulation of microglial cells and macrophages reactive to various pathological conditions.     

Does the CLL B lymphocyte correspond to expansion of an immature B clone or to expansion of a distinct subpopulation of B cells?

Most CLL cases correspond to proliferation of a B-cell clone characterized by (1) low amounts of SmIg, (2) the presence of receptors for mouse red blood cells, (3) the presence of a 67-kd antigenic determinant recognized by CD5 monoclonal antibodies, also present in normal T cells, (4) the ability of these cells to differentiate in vitro, and (5) the ability at least for some clones to differentiate and secrete immunoglobulins in vivo. The normal counterpart to this B-cell clone corresponds to a small subpopulation of lymphocytes, present at the edge of the germinal center in human lymph nodes. Interestingly, this subpopulation appears to constitute a substantial part of the B-cell population in 20-week-old fetal lymph nodes and spleen. These results have induced most authors to assume that the CLL B lymphocyte corresponds to proliferation of an immature B-cell clone, arrested at an intermediate stage between pre-B cells and mature B cells. However, this hypothesis does not explain the high frequency with which hypogammaglobulinemia and autoimmune hemolytic anemia are found in B CLL. In this work, we discuss the possibility that the CLL B lymphocyte corresponds to proliferation of a B-cell line, whose counterpart in the mouse is the Ly1 B, Lyb5+ subpopulation.     

Chronic alcohol consumption decreases the percentage and number of NK cells in the peripheral lymph nodes and exacerbates B16BL6 melanoma metastasis into the draining lymph nodes

NK cells in the lymph nodes play important roles in inhibiting tumor metastasis into draining lymph nodes. Previously, we reported that chronic alcohol consumption interferes with NK cell trafficking from the bone marrow to the spleen. Herein, we found that alcohol consumption decreases the numbers of NK cells in lymph nodes. Adoptive transfer experiments indicated that continued exposure of donor splenocytes to alcohol inhibits NK but not T cell trafficking to lymph nodes. Alcohol did not negatively affect CCR7⁺ and CXCR3⁺ NK cells, but decreased the percentage and number of CD62L⁺ NK cells in the spleen, which are an important source of NK cell trafficking into the lymph nodes. These data suggest that modulation of the microenvironment associated with alcohol consumption impairs the trafficking of NK cells to lymph nodes. The decreased number of NK cells in the lymph nodes was associated with increased melanoma metastasis into the draining lymph nodes.