Biomedical subjects

E C Butcher

Publications and source records attributed to E C Butcher.

At least 55 records · Page 3Linked to original sources

PubMed1998

Molecular mechanisms of lymphocyte homing to peripheral lymph nodes.

To characterize the adhesion cascade that directs lymphocyte homing to peripheral lymph nodes (PLNs), we investigated the molecular mechanisms of lymphocyte interactions with the microvasculature of subiliac lymph nodes. We found that endogenous white blood cells and adoptively transferred lymph node lymphocytes (LNCs) tethered and rolled in postcapillary high endothelial venules (HEVs) and to a lesser extent in collecting venules. Similarly, firm arrest occurred nearly exclusively in the paracortical HEVs. Endogenous polymorphonuclear (PMNs) and mononuclear leukocytes (MNLs) attached and rolled in HEVs at similar frequencies, but only MNLs arrested suggesting that the events downstream of primary rolling interactions critically determine the specificity of lymphocyte recruitment. Antibody inhibition studies revealed that L-selectin was responsible for attachment and rolling of LNCs, and that LFA-1 was essential for sticking. LFA-1-dependent arrest was also abolished by pertussis toxin, implicating a requirement for G alpha i--protein-linked signaling. alpha 4 integrins, which play a critical role in lymphocyte homing to Peyer's Patches, made no significant contribution to attachment, rolling, or sticking in resting PLNs. Velocity analysis of interacting LNCs revealed no detectable contribution by LFA-1 to rolling. Taken together, our results suggest that lymphocyte- HEV interactions within PLNs are almost exclusively initiated by L-selectin followed by a G protein-coupled lymphocyte-specific activation event and activation-induced engagement of LFA-1. These events constitute a unique adhesion cascade that dictates the specificity of lymphocyte homing to PLNs.

Adoptive Transfer↗

PubMed1998

Chemokines and the arrest of lymphocytes rolling under flow conditions.

Circulating lymphocytes are recruited from the blood to the tissue by rolling along the endothelium until being stopped by a signaling event linked to the Gialpha subunit of a heterotrimeric GTP-binding protein; that event then triggers rapid integrin-dependent adhesion. Four chemokines are now shown to induce such adhesion to intercellular adhesion molecule-1 and to induce arrest of rolling cells within 1 second under flow conditions similar to those of blood. SDF-1 (also called PBSF), 6-C-kine (also called Exodus-2), and MIP-3beta (also called ELC or Exodus-3) induced adhesion of most circulating lymphocytes, including most CD4+ T cells; and MIP-3alpha (also called LARC or Exodus-1) triggered adhesion of memory, but not naïve, CD4+ T cells. Thus, chemokines can regulate the arrest of lymphocyte subsets under flowing conditions, which may allow them to control lymphocyte-endothelial cell recognition and lymphocyte recruitment in vivo.

Antigens, Surface↗

PubMed1998

Tyrphostin AG490, a tyrosine kinase inhibitor, blocks actively induced experimental autoimmune encephalomyelitis.

Migration of lymphocytes from blood into the brain is a critical event in the pathogenesis of multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis (EAE). Previous observations made in our laboratory showed that protein tyrosine kinase inhibitors were able to block lymphocyte adhesion to brain endothelium and prevent the entry of encephalitogenic T cell lines into the brain of SJL/J mice. Here we show that systemic administration of the protein tyrosine kinase inhibitor, tyrphostin AG490, blocks the development of actively induced EAE in a dose-dependent manner. Administration of 1 mg of drug daily significantly decreased the severity of the disease, while 3 mg of AG490 daily totally blocked the disease in 62% of treated animals, and in those that developed the disease, paralysis was delayed and clinical score was significantly reduced. Blood leukocytes isolated from mice treated with tyrphostin AG490 were less adhesive on VCAM-1 and fibronectin, when compared with control animals. AG490 treatment had no effect on the proliferation by antigen-stimulated peripheral lymph nodes cells. Interestingly, cells obtained from draining lymph nodes in AG490-treated animals and stimulated with antigen secreted two times more IFN-gamma and four times more IL-10, when compared with control animals, whereas no difference was observed in TNF-alpha production. Our results suggest that tyrphostin AG490 may have therapeutic potential by blocking tyrosine kinase activities involved in key mechanisms leading to demyelinating diseases of the central nervous system.

Animals↗

PubMed1998

Expression of the mucosal homing receptor alpha4beta7 correlates with the ability of CD8+ memory T cells to clear rotavirus infection.

The integrin alpha4beta7 plays an important role in lymphocyte homing to mucosal lymphoid tissues and has been shown to define a subpopulation of memory T cells capable of homing to intestinal sites. Here we have used a well-characterized intestinal virus, murine rotavirus, to investigate whether memory/effector function for an intestinal pathogen is associated with alpha4beta7 expression. Alpha4beta7(hi) memory phenotype (CD44hi), alpha4beta7- memory phenotype, and presumptively naive (CD44(lo)) CD8+ T lymphocytes from rotavirus-infected mice were sorted and transferred into Rag-2 (T- and B-cell-deficient) recipients that were chronically infected with murine rotavirus. Alpha4beta7(hi) memory phenotype CD8+ cells were highly efficient at clearing rotavirus infection, alpha4beta7- memory cells were inefficient or ineffective, depending on the cell numbers transferred, and CD44(lo) cells were completely unable to clear chronic rotavirus infection. These data demonstrate that functional memory for rotavirus resides primarily in memory phenotype cells that display the mucosal homing receptor alpha4beta7.

Animals↗

PubMed1998

Human airway epithelial monolayers promote selective transmigration of memory T cells: a transepithelial model of lymphocyte migration into the airways.

It has previously been demonstrated that T lymphocytes in the conducting airways express a pattern of adhesion molecules that are uniquely different from T lymphocytes found circulating in peripheral blood. To examine the role of airway epithelia in the determination of migratory capacity for human monocyte and lymphocyte populations in vivo, we have developed an in vitro transepithelial migration model using the human transformed bronchial epithelial cell line BEAS-2B S.6. In this study, we have demonstrated the preferential migration of human peripheral blood mononuclear cells (PBMC) across BEAS-2B S.6 cell monolayers in a physiologically appropriate direction (basal to apical epithelial cell surface). Stimulation of BEAS-2B S.6 cells with a combination of interferon-gamma and tumor necrosis factor-alpha upregulated basal-to-apical transepithelial migration by at least twofold. Monocytes migrated most efficiently, but subpopulations of CD19(+) B cells and CD2(+) cells were also recruited across epithelial cell monolayers. In the T lymphocyte subset of PBMC, CD45RO+ "memory" cells migrated preferentially. In addition, CD4(+) cells exhibited a significantly greater capacity to migrate across airway epithelium compared with CD8(+) cells. Migrated CD4(+) cells were predominantly CD29(high)/CD26(high), and within this subset uniformly expressed CD62L (L-selectin) at an intermediate level. PBMC migration across BEAS-2B S.6 cells was significantly inhibited by pertussis toxin; this result implicates a G protein signaling event as an important mediator of lymphocyte/monocyte transepithelial migration. On the basis of these data, we conclude that bronchial epithelium provides a unique microenvironment that supports the selective, G protein-dependent migration of memory T cells.

Bronchi↗

PubMed1998

Complexity and differential expression of carbohydrate epitopes associated with L-selectin recognition of high endothelial venules.

Carbohydrate ligands for lymphocyte L-selectin are expressed on high endothelial venules (HEVs) in peripheral lymph nodes and sites of chronic inflammation and mediate the recruitment of lymphocytes from the blood into these tissues. In the mouse, these ligands, collectively termed the peripheral lymph node addressin (PNAd), have been shown to contain fucose, sialic acid, and sulfate and to include several HEV glycoproteins including GlyCAM-1, CD34, and MAdCAM-1. Monoclonal antibody (MAb) MECA-79, which binds a sulfate-dependent epitope, recognizes PNAd in both mouse and man. In humans, only CD34 has been identified among the glycoprotein species that react with MECA-79. Although P-selectin is highly expressed in tonsil HEVs, it was not found to react with MECA-79 or to support L-selectin-mediated lymphocyte rolling. To further characterize human PNAd, MAbs were developed against purified PNAd immunoisolated from human tonsil. MAbs JG-1, JG-5, JG-9, and JG-10, like MECA-79, bind HEVs in human tonsil and react similarly in Western blots, and JG-9 and JG-10 also block lymphocyte rolling on purified PNAd. In addition, by competitive ELISA on purified tonsil PNAd, all MAbs were found to react with overlapping epitopes. However, JG-1, JG-5, JG-9, and JG-10 do not recognize mouse PNAd, and unlike MECA-79, they recognize determinants that are sensitive to neuraminidase. Strikingly, the epitope recognized by JG-1, although abundant in tonsil and peripheral lymph node, is absent from appendix HEVs or HEVs in some samples of chronically inflamed skin, even though these HEVs are MECA-79 reactive. Moreover, although JG-5 and JG-9 react well with tonsil, peripheral lymph node, and inflamed skin HEVs, they react only with occasional endothelial cells in appendix tissues. These findings point to significant diversity in the carbohydrate determinants expressed by HEVs and recognized by L-selectin and demonstrate their differential representation in different sites in vivo. These antibodies should be useful in probing the precise structure of human L-selectin ligands.

Animals↗

PubMed1997

Multistep navigation and the combinatorial control of leukocyte chemotaxis.

Cells migrating within tissues may encounter multiple chemoattractant signals in complex spatial and temporal patterns. To understand leukocyte navigation in such settings, we have explored the migratory behavior of neutrophils in model scenarios where they are presented with two chemoattractant sources in various configurations. We show that, over a wide range of conditions, neutrophils can migrate "down" a local chemoattractant gradient in response to a distant gradient of a different chemoattractant. Furthermore, cells can chemotax effectively to a secondary distant agonist after migrating up a primary gradient into a saturating, nonorienting concentration of an initial attractant. Together, these observations suggest the potential for cells' step-by-step navigation from one gradient to another in complex chemoattractant fields. The importance of such sequential navigation is confirmed here in a model system in which neutrophil homing to a defined domain (a) requires serial responses to agonists presented in a defined spatial array, and (b) is a function of both the agonist combination and the sequence in which gradients are encountered. We propose a multistep model of chemoattractant-directed migration, which requires that leukocytes display multiple chemoattractant receptors for successful homing and provides for combinatorial determination of microenvironmental localization.

Chemotactic Factors↗

PubMed1997

Anti-CD43 inhibits monocyte-endothelial adhesion in inflammation and atherogenesis.

Recruitment of blood monocytes into tissues is a central event in the inflammatory response and in atherogenesis. The mechanisms leading to monocyte adhesion and migration through endothelium are not completely defined. We recently reported that MAb L11, against the leukocyte sialomucin CD43, blocks T-lymphocyte binding to lymph node and Peyer's patch high endothelial venules (HEV) and inhibits T-cell extravasation from the blood into organized secondary lymphoid tissues. We have now assessed the ability of L11 to inhibit monocyte-endothelial (EC) interactions and trafficking. L11 blocks binding of WEHI78/24 cells, a murine monocytoid cell line, to inflamed lymph node HEV and inhibits recruitment of monocytes and neutrophils to thioglycollate-inflamed peritoneum. Because monocyte adhesion to the endothelium and diapedesis in lesion-prone regions of the vasculature is among the earliest events in atherogenesis, leading to formation of lipid-laden foam cells, the ability of L11 to block monocyte recognition of aortic endothelial cells was assessed in a novel ex vivo assay of monocyte binding to intact rabbit aortic endothelium. Cholesterol feeding of rabbits induces enhanced aortic adhesiveness for monocytes and WEHI78/24 monocytoid cells, and this adhesion is inhibited by L11. The inhibitory effect of L11 is additive with that of a cocktail of anti-L-selectin and anti-alpha4 and beta2 integrin monoclonal antibodies. Thus, CD43 represents a novel target for manipulation of monocyte recruitment in inflammation and atherogenesis.

Animals↗

PubMed1997

Elevation of intracellular cAMP inhibits RhoA activation and integrin-dependent leukocyte adhesion induced by chemoattractants.

Chemoattractant receptors of the serpentine, heterotrimeric Galphai protein-linked family can activate leukocyte integrins and in this role regulate leukocyte traffic and cell-cell interactions in immune and inflammatory responses. Using a mouse lymphoid cell line transfected with human formyl peptide or interleukin-8 receptors and normal human neutrophils as models, we show that cAMP functions as a gating element on the chemoattractant-induced rho-dependent signaling pathway leading to leukocyte integrin activation and adhesion. cAMP, acting through protein kinase A, inhibits chemoattractant-triggered integrin-dependent leukocyte adhesion. cAMP also prevents guanine nucleotide exchange on RhoA, a small GTP-binding protein of the rho subfamily, which is activated in seconds by chemoattractants. In contrast, chemoattractant-triggered intracellular calcium elevation is unaffected by cAMP, and cAMP has no effect on rho-dependent adhesion and RhoA guanine nucleotide exchange triggered through the independent protein kinase C pathway. These data suggest that cAMP-induced inhibition of rho activation may be responsible for the anti-adhesive effect of cAMP and may contribute to the anti-inflammatory activity of cAMP elevating agonists and drugs. Moreover, the findings extend the concept of cyclic nucleotide gating as a broadly important mechanism in the regulation of intracellular signaling pathways and the cellular activities they control.

Adult↗

PubMed1997

Expression of mucosal homing receptor alpha4beta7 by circulating CD4+ cells with memory for intestinal rotavirus.

The integrin alpha4beta7 mediates lymphocyte binding to mucosal addressin cell adhesion molecule-1, and its expression defines lymphocytes capable of trafficking through the intestines and the intestinal lymphoid tissues. We examined the ability of discrete alpha4beta7(hi) and alpha4beta7- subsets of circulating memory phenotype (CD45RA-) CD4+ T cells to proliferate in response to rotavirus, a ubiquitous intestinal pathogen. alpha4beta7(hi) memory (CD45RA-) CD4+ T cells displayed much greater reactivity to rotavirus than alpha4beta7- memory or naive (CD45RA+) CD4+ T cells. In contrast, alpha4beta7- memory cells were the predominant population responsive to mumps antigen after intramuscular vaccination. Our results are consistent with the conclusion that natural rotavirus infection, an enteric pathogen, results in a specific circulating memory CD4+ response that is largely limited to the gut-homing alpha4beta7+ subpopulation. This phenotype is not shared with memory cells elicited by intramuscular immunization (shown here) or by skin contact allergens. The results support the hypothesis that gut trafficking memory CD4+ T cells comprise cellular memory for intestinal antigens and suggest that regulated expression of alpha4beta7 helps target and segregate intestinal versus systemic immune response.

Adult↗

PubMed1997

Vascular adhesion protein 1 (VAP-1) mediates lymphocyte subtype-specific, selectin-independent recognition of vascular endothelium in human lymph nodes.

Interactions between lymphocyte surface receptors and their ligands on vascular endothelial cells regulate the exit of lymphocytes from the circulation. Distinct subsets of mononuclear cells bind to high endothelial venules (HEVs) in different lymphoid organs to a different extent, but the molecular mechanisms behind this selectivity have remained poorly characterized. Here we show that vascular adhesion protein-1 (VAP-1) mediates subtype-specific binding of CD8-positive T cells and natural killer cells to human endothelium. VAP-1-dependent, oligosaccharide-dependent peripheral lymph node (PLN) HEV adhesion under shear was independent of L-selectin, P-selectin glycoprotein ligand 1, and alpha4 integrins, the known lymphocyte receptors involved in the initial recognition of endothelial cells. PLN HEV adhesion was also critically dependent on peripheral lymph node vascular addressins (PNAds), but lymphocyte L-selectin was absolutely required for PNAd binding. Most lymphocytes relied on both PNAd and VAP-1 in HEV binding. The overlapping function of L-selectin ligands and VAP-1 in PLN introduces a new control point into the lymphocyte extravasation process. Finally, intravital microscopy revealed that VAP-1 is involved in initial interactions between human lymphocytes and endothelial cells in inflamed rabbit mesenterial venules in vivo. In conclusion, VAP-1 is a novel contact-initiating ligand that discriminates between different subpopulations of mononuclear cells and is an appealing target for selective modulation of adhesion of CD8- and CD16-positive effector cells.

Adult↗

PubMed1997

Homing of naive and memory T lymphocyte subsets to Peyer's patches, lymph nodes, and spleen.

The specificity and efficiency of extravasation of subsets of memory and naive lymphocytes into organized lymphoid tissues has been the subject of recent controversy, but has not been directly assessed in physiologic systems. Here, we compare the lymphoid organ homing of naive and phenotypically defined memory T cells, focusing on memory subsets differentially expressing the integrin receptor alpha4beta7, which is implicated in homing to mucosal sites. Naive T cells (CD44(low), Thy1+) home to all secondary lymphoid organs. Alpha4beta7(high) memory-phenotype (CD44(high)) T cells home to Peyer's patches as efficiently as naive lymphocytes, whereas alpha4beta7- memory-phenotype T cells are essentially excluded from entry into these mucosal lymphoid organs. In contrast, alpha4beta7- memory-phenotype cells home approximately twice as efficiently as alpha4beta7(high) T cells to peripheral lymph nodes, but only approximately 20% as well as naive T cells. Interestingly, the spleen recruits all three identified subsets with nearly equal efficiency. The relative subset localization is similar 2.5 h after injection and after overnight trafficking, suggesting that memory cells can directly extravasate from blood into Peyer's Patches and lymph nodes. We conclude that subsets of memory T cells defined by patterns of homing receptor expression display differential homing to organized lymphoid tissues, an ability that may facilitate homeostatic interactions and target contributions to specialized regional immune responses.

Animals↗

PubMed1997

Structure-function analysis of the integrin beta 7 subunit: identification of domains involved in adhesion to MAdCAM-1.

Beta 7 integrins serve special roles in mucosal immunity. Alpha 4 beta 7-mediated adhesion to mucosal addressin cell adhesion molecule-1 (MAdCAM-1) directs lymphocyte homing to the gut, and alpha E beta 7 mediates binding of lymphocytes to E-cadherin on epithelial cells. Since alpha 4 beta 7 mediates adhesion to MAdCAM-1 but alpha 4 beta 1 does not, we used beta 7/beta 1 chimeras to directly assess the importance of specific regions of beta 7 in MAdCAM-1 binding. We found a region of beta 7 (residues 46-386) that accounts for specificity of alpha 4 beta 7 binding to MAdCAM-1. We also used human/mouse and human/rat chimeric beta 7 subunits to map epitopes recognized by fifteen anti-beta 7 mAbs. Six of seven Abs that block adhesion to MAdCAM-1 and E-cadherin (Fib 21, 22, 27, 30, 504; Act-1) mapped to amino acid residues 176-250. Residues 176-250 lie within the region of beta 7 that specifies MAdCAM-1 binding and also within a region that has a predicted structure homologous to the metal ion-dependent adhesion site (MIDAS) domains of the integrin subunits alpha L and alpha M. Three new Abs that recognize beta 7 in the presence of Mn2+, but not Ca2+, and promote adhesion to MAdCAM-1, mapped to amino acids 46-149. One blocking and five other Abs mapped to other regions (amino acids 387-725). We conclude that a MIDAS-like domain serves a critical role in beta 7 integrin-mediated adhesion.

Animals↗

PubMed1997

Novel vascular molecule involved in monocyte adhesion to aortic endothelium in models of atherogenesis.

Adhesion of monocytes to the endothelium in lesion-prone areas is one of the earliest events in fatty streak formation leading to atherogenesis. The molecular basis of increased monocyte adhesion is not fully characterized. We have identified a novel vascular monocyte adhesion-associated protein, VMAP-1, that plays a role in adhesion of monocytes to activated endothelium. Originally selected for its ability to block binding of a mouse monocyte-like cell line (WEHI78/24) to cytokine- or LPS-stimulated cultured mouse endothelial cells in vitro, antiVMAP-1 mAb LM151 cross-reacts with rabbit endothelium and blocks binding of human monocytes to cultured rabbit aortic endothelial cells stimulated with minimally modified low density lipoprotein, thought to be a physiologically relevant atherogenic stimulus. Most importantly, LM151 prevents adhesion of normal monocytes and monocytoid cells to intact aortic endothelium from cholesterol-fed rabbits in an ex vivo assay. VMAP-1 is a 50-kD protein. Immunohistology of vessels reveals focal constitutive expression in aorta and other large vessels. VMAP-1 is thus a novel vascular adhesion-associated protein that appears to play a critical role in monocyte adhesion to aortic endothelial cells in atherogenesis in vivo.

Animals↗

PubMed1997

Specialization of mucosal follicular dendritic cells revealed by mucosal addressin-cell adhesion molecule-1 display.

Follicular dendritic cells (FDC) in the mucosal lymphoid organs, Peyer's patches (PP), display mucosal vascular addressin-cell adhesion molecule-1 (MAdCAM-1). MAdCAM-1 decorates interlacing dendritic cells throughout PP follicles and is accentuated on FDC of the germinal center (GC) light zone and on "junctional" dendritic cells overlapping the B/T border and subepithelial dome region, sites associated with microenvironmental homing decisions. In contrast, MAdCAM-1 is rarely displayed by coronal or junctional FDC in peripheral lymph node follicles and is largely confined to the GC after lymph node immunization. FDC-associated MAdCAM-1 plays a prominent role in lymphocyte adhesion to GC in PP frozen sections and participates significantly in binding to GC in chronically stimulated lymph nodes and spleen, but not to GC in lymph nodes after primary immunization (where binding is dominated by vascular cell adhesion molecule-1). Differential display of MAdCAM-1 by FDC could contribute to the specialization of mucosal vs nonmucosal immune responses.

Animals↗

PubMed1997

Anti-CD43 inhibition of T cell homing.

The homing of lymphocytes from the blood is controlled by specialized processes of lymphocyte-endothelial cell interaction. Interference with these processes offers the potential to manipulate lymphocyte traffic, and thus to modulate normal and pathologic immune and inflammatory responses. We selected antilymphocyte monoclonal antibodies (mAbs) for inhibition of lymphocyte binding in vitro to lymph node high endothelial venules (HEV), specialized vessels that support lymphocyte recruitment into lymph nodes. mAb L11 blocks T cell binding to lymph node and Peyer's patch HEV and inhibits T cell extravasation from the blood into organized secondary lymphoid tissues. In contrast, L11 has no effect on lymphocyte binding to purified vascular ligands for L-selectin, alpha4beta7, or LFA-1, suggesting that it inhibits by a novel mechanism. The L11 antigen is CD43, a sialomucin implicated in vitro in regulation of lymphocyte activation, whose expression is often dysregulated in the Wiskott-Aldrich syndrome. CD43 represents a novel target for experimental and therapeutic manipulation of lymphocyte traffic and may help regulate T cell distribution in vivo.

Animals↗

PubMed1997

Novel method for following lymphocyte traffic in mice using [3H]glycerol labeling.

We describe a new method based on radioactive metabolic labeling with [3H]glycerol to study the lymphocyte trafficking in mice. Lymphocyte labeling with [3H]glycerol is time- and dose-dependent. Radioactive leaking is less significant than in 51Cr-labeled cells. Lymphocytes, labeled with [3H]glycerol, with 51Cr, or with both labels together show the same pattern of homing to Peyer's patches (PP), peripheral and mesenteric lymph nodes and spleen and homing shows the expected dependence on pertussis toxin (PTX)-sensitive signaling, suggesting that the labeling procedure with [3H]glycerol does not affect lymphocyte trafficking properties. Tissue accumulation can be readily assessed by scintillation counting of sonicated samples obtained after perfusion of the vasculature with saline to remove blood. Moreover, we show that cell labeling with [3H]glycerol provides improved sensitivity in assessing the accumulation of small numbers of labeled cells in non-lymphoid organs, and permits identification of homed leukocytes in histologic sections.

Animals↗

PubMed1997

Differential expression of tissue-specific adhesion molecules on human circulating antibody-forming cells after systemic, enteric, and nasal immunizations. A molecular basis for the compartmentalization of effector B cell responses.

Expression of the adhesion molecules CD44, L-selectin (CD62L), and integrin alpha 4 beta 7 by antibody-secreting cells (ASC) was examined in human volunteers after oral, rectal, intranasal, or systemic immunization with cholera toxin B subunit. Almost all blood ASC, irrespective of immunization route, isotype (IgG and IgA), and immunogen, expressed CD44. On the other hand, marked differences were observed between systemically and intestinally induced ASC with respect to expression of integrin alpha 4 beta 7 and L-selectin, adhesion molecules conferring tissue specificity for mucosal tissues and peripheral lymph nodes, respectively. Thus, most ASC induced at systemic sites expressed L-selectin, whereas only a smaller proportion of ASC expressed alpha 4 beta 7. In contrast, virtually all IgA- and even IgG-ASC detected after peroral and rectal immunizations expressed alpha 4 beta 7, with only a minor fraction of these cells expressing L-selectin. Circulating ASC induced by intranasal immunization displayed a more promiscuous pattern of adhesion molecules, with a large majority of ASC coexpressing L-selectin and alpha 4 beta 7. These results demonstrate that circulating ASC induced by mucosal and systemic immunization express different sets of adhesion molecules. Furthermore, these findings provide for the first time evidence for differential expression of adhesion molecules on circulating ASC originating from different mucosal sites. Collectively, these results may explain the anatomical division of mucosal and systemic immune responses in humans as well as the compartmentalization of mucosal immune responses initiated in the upper vs. the lower aerodigestive tract.

Administration, Inhalation↗