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Biomedical subjects

A Poggi

Publications and source records attributed to A Poggi.

At least 19 recordsLinked to original sources
PubMed1998

Involvement of dihydropyridine-sensitive calcium channels in human dendritic cell function. Competition by HIV-1 Tat.

The entry of extracellular calcium in leukocytes mediates several cellular processes; however, unlike in excitable tissues, the underlying molecular mechanisms are poorly defined. In this paper we provide phenotypical and biochemical evidence that peripheral blood-derived human dendritic cells express dihydropyridine-sensitive calcium channels. Exposure to the dihydropyridine drug nifedipine, which binds L-type calcium channels blocking calcium influx, prevents two dendritic cell functions that are dependent on extracellular calcium entry: apoptotic body engulfment and interleukin-12 production induced by cross-linking of the surface lectin NKRP1A. It is known that exogenous human immunodeficiency virus, type 1 Tat affects several Ca2+-dependent immune cell responses. Here we demonstrate that Tat inhibits apoptotic body engulfment and interleukin-12 production by blocking extracellular calcium influx. This inhibition is prevented by the calcium channel agonist dihydropyridine derivative Bay K 8644, suggesting the involvement of L-type calcium channels. This hypothesis is further supported by the observation that Tat and dihydropyridine drugs compete for binding to dendritic cells. Taken together, these findings indicate that exogenous Tat exerts its inhibitory effects on dendritic cells by blocking dihydropyridine-sensitive L-type calcium channels.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1998

CD14+ CD34+ peripheral blood mononuclear cells migrate across endothelium and give rise to immunostimulatory dendritic cells.

We describe a subset of peripheral CD14+ cells, coexpressing the CD34 progenitor marker and able to migrate across endothelial cell monolayers. On culture with granulocyte-macrophage-CSF, this population differentiated into dendritic cells expressing CD83, CD80, HLA-DR(bright), CD86, and CD54. These dendritic cells were immunostimulatory, in that they induced proliferation of allogenic and tetanus toxoid-specific T lymphocytes. The CD14+ CD34+ population expressed higher levels of platelet endothelial cell adhesion molecule-1 (PECAM-1) and alpha4beta1 integrin than the CD14+ CD34- counterpart, being dull positive for other integrins. Using stably transfected PECAM-1+, VCAM-1+, or ICAM-1+ cells, we found that PECAM-1 and, to a lesser extent, VCAM-1, could support transmigration of CD14+ CD34+ cells, whereas the alphaL-ICAM-1 interaction was involved in cell adhesion. PECAM-1-driven transmigration was conceivably dependent on a haptotactic gradient, as it was reduced by 80% across NIH3T3 cells transfected with the PECAM-1-delta cyto deletion mutant. This mutant lacks the cytoplasmic tail and displays a reduced tendency to localize at the intercellular junctions, thus failing to form a molecular junctional gradient. Once differentiated, dendritic cells derived from CD14+ CD34+ precursors retained their transendothelial migratory capability, using both PECAM-1 and ICAM-1 for transmigration. We suggest that a subset of CD14+ CD34+ circulating leukocytes can localize to peripheral tissues and differentiate into functional dendritic cells, thus representing a functional reservoir of potential APC. PECAM-1, constitutively expressed on vascular endothelium, is likely to play a relevant role in the egress of this population from the bloodstream.

Antigens, CD34↗
PubMed1998

IL-12-induced up-regulation of NKRP1A expression in human NK cells and consequent NKRP1A-mediated down-regulation of NK cell activation.

IL-12, in contrast to IL-2, strongly up-regulated the expression of the NKRP1A lectin molecule on human NK cells. This effect appeared to be specific for NKRP1A as the expression of other functional NK cell surface molecules such as CD16 and different killer inhibitory receptors (KIR) including CD158a and CD158b, p70 and p140 were not affected by culture in IL-12. In addition, we found that polyclonal or clonal NK cell populations derived in the presence of IL-2 displayed an increased expression of NKRP1A after culture in IL-12. The IL-12-induced NKRP1A expression was time and dose dependent, reaching a maximum by 7 days of culture in the presence of 2 ng/ml IL-12 and it was inhibited by the addition of anti-IL-12 monoclonal antibody. The IL-12-dependent NKRP1A up-regulation was abrogated by the incubation of NK cells with actinomycin D, thus suggesting that IL-12 induces de novo transcription of NKRP1A mRNA. Functional analysis revealed that the engagement of the NKRP1A molecule in IL-12- but not in IL-2-cultured NK cells leads to a strong inhibition of the cytolytic activity induced by cross-linking of CD16 or p46, a recently described NK cell-specific triggering surface molecule. Our findings suggest that IL-12 up-regulates the expression of NKRP1A which, in turn, can regulate NK cell activation induced via different triggering pathways. This would imply that NKRP1A-mediated functions may be regulatd by the cytokine microenvironment that NK cells may encounter at inflammatory sites.

Antigens, Surface↗
PubMed1998

p40/LAIR-1 regulates the differentiation of peripheral blood precursors to dendritic cells induced by granulocyte-monocyte colony-stimulating factor.

p40/LAIR-1, a member of the immunoglobulin superfamily, is a surface molecule broadly distributed among leukocytes which has been shown to down-regulate T and NK cell activation. In this study, we show that p40/LAIR-1 is highly expressed in CD14+ peripheral blood mononuclear cells (PBMC). When cultured in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF) for 10-14 days, CD14+ cells acquired morphologic and phenotypic features (i.e. loss of CD14 and expression of CD80bright and CD86bright) typical of dendritic cells (DC) and lost the expression of p40/LAIR-1. Engagement of p40/LAIR-1 (but not of CD58) by specific monoclonal antibodies prevented CD14+ PBMC differentiation into DC; when cultured in the presence of GM- CSF upon p40/LAIR-1 cross-linking, the resulting cells were CD14+CD80(dull)CD86(dull) and displayed a macrophage-like morphology. We have recently demonstrated that peripheral blood CD14+ cells co-expressing the CD34 progenitor marker represent the circulating precursors of CD83+ DC. Herein we show that cross-linking of p40/LAIR-1 prevented the maturation of CD14+CD34+ cells into CD83+ DC. This effect appears to be consequent to the impairment of GM-CSF receptor-mediated activation signaling. Indeed, triggering of GM-CSF receptors in both CD14+ and CD14+CD34+ cells led to increases in the intracellular free calcium concentrations which were inhibited by p40/LAIR-1 engagement. Taken together, these data suggest a possible regulating role played by p40/LAIR-1 in the process of differentiation from peripheral blood precursors into DC induced by GM-CSF.

Calcium↗
PubMed1998

Tumor-driven matrix invasion by infiltrating lymphocytes: involvement of the alpha1 integrin I-domain.

Here we show that tumor cells (TC) from renal cancers regulate the migratory properties of autologous tumor-infiltrating lymphocytes (TIL), enhancing their ability to invade the extracellular matrix. A similar effect is exerted by human recombinant macrophage chemotactic protein 1 (MCP-1) and IL-8, chemokines known to increase T lymphocyte migration both across vascular endothelium and subendothelial matrix. We found that TC freshly derived from renal cell carcinoma surgical specimens constitutively secrete both IL-8 and MCP-1 and that TIL express both specific receptors. TIL matrix invasion elicited by TC is inhibited by the addition of neutralizing antisera specific for IL-8 and MCP-1, demonstrating the direct relationship between chemokine release by TC and TIL invasion. Of note, TIL invasion of the extracellular matrix requires the alpha1 integrin, which acts through its I-domain that is upregulated upon culture with MCP-1 and IL-8. Collectively, these findings suggest that TC may actively recruit TIL via the release of chemotactic factors that enhance an alpha1 integrin-mediated pathway of matrix invasion.

Antigens, CD↗
PubMed1997

Close phenotypic and functional similarities between human and murine alphabeta T cells expressing invariant TCR alpha-chains.

Several studies have demonstrated the existence of a murine NK1.1+ alphabeta T cell subset expressing V alpha14+ TCR alpha-chains with highly conserved invariant junctional sequences and able to secrete Th2 cytokines when exposed to CD1+ stimulator cells. In humans, alphabeta T cells carrying invariant V alpha24+ TCR alpha-chains highly homologous to those expressed by murine NK1.1 cells have been recently described. Here we show that these cells (referred to as V alpha24inv T cells) and murine NK1.1+ alphabeta T cells resemble each other in several ways. First, like their murine counterparts, T cells expressing high levels of V alpha24inv TCRs can be either CD4- CD8- double negative (DN) or CD4+, but they never express heterodimeric CD8 molecules. Second, most V alpha24inv T cells are brightly stained by NKRP1-specific mAb but not by mAb directed against other type II transmembrane proteins of the NK complex. Third, DN and particularly CD4+ V alpha24inv T cells are greatly enriched for IL-4 producers. The concomitant expression of highly conserved TCRs of a particular set of NK markers and of Th2 cytokines in human and murine alphabeta T cells suggests a coordinate acquisition of these phenotypic and functional properties. Furthermore, the relatively high frequency of human V alpha24inv T cells, which are presently shown to represent on average 1/500 PBL, and the high interindividual variations of the size of this cell subset under physiologic conditions go for a major role played by alphabeta T cells carrying invariant TCR in a large array of immune responses.

Animals↗
PubMed1997

NKRP1A molecule is involved in transendothelial migration of CD4+ human T lymphocytes.

Among human CD4+ T lymphocytes, 5-20% express the C-type lectin molecule NKRP1A. Interestingly, CD4+ NKRP1A+ T lymphocytes express high levels of beta 1 and beta 2 integrins, thus representing a T lymphocyte subset that can possibly adhere and migrate through vascular endothelium. Indeed, resting CD4+ NKRP1A+ lymphocytes, differently from the CD4+ NKRP1A- subset, migrated across endothelial cell monolayers in a Transwell chamber system. This transendothelial migration was strongly reduced after pre-treatment with an anti-NKRP1A monoclonal antibody (mAb). In addition, the NKRP1A negative Jurkatt CD4+ T-cell line that had been stably transfected with NKRP1A cDNA, migrated more rapidly and efficiently than untransfected Jurkatt cells. Finally, mAb-mediated cross-linking of NKRP1A molecule in CD4+ T lymphocytes induced the upregulation of the LFA1 Mg2+ binding site as well as beta 1 and beta 2 integrin chains. Altogether, these findings indicate that NKRP1A molecule is involved in transendothelial migration of resting CD4+ T lymphocytes.

Antigens, Surface↗
PubMed1997

The selective engulfment of apoptotic bodies by dendritic cells is mediated by the alpha(v)beta3 integrin and requires intracellular and extracellular calcium.

Dendritic cells derived in vitro from monocytes are known to be poor phagocytes. Here we show that, unlike macrophages, monocyte-derived dendritic cells indeed fail to take up opsonized particles or necrotic cells; however, apoptotic bodies are efficiently engulfed by dendritic cells. The temperature dependence and the sensitivity to cytochalasin D indicate that the apoptotic body engulfment is representative of early stages of phagocytosis. Inhibition studies with ligands for surface molecules involved in recognition of apoptotic bodies, such as vitronectin receptor, CD36 and phosphatidylserine receptor, revealed that apoptotic body engulfment by dendritic cells is mediated preferentially by the vitronectin receptor alpha(v)beta3, while all the receptors, with different efficiency, are engaged in phagocytosis of apoptotic bodies by macrophages. The interaction between apoptotic bodies and dendritic cells elicits a rise in intracellular free calcium concentration ([Ca2+]i) which is essential for the process of engulfment. Either intra- or extracellular Ca2+ buffering inhibits apoptotic body engulfment by dendritic cells and [Ca2+]i increases, indicating the involvement of both intra- and extracellular Ca2+. In contrast, Ca2+ mobilization is dispensable for macrophage phagocytosis of apoptotic bodies. The different requirements of Ca2+ in macrophages and dendritic cells is possibly due to the differential usage of phagocytic receptors (CD36 vs. alpha(v)beta3) and might reflect different fates of apoptotic bodies in the two cell types.

Apoptosis↗
PubMed1997

Phenotypic and functional analysis of CD4+ NKRP1A+ human T lymphocytes. Direct evidence that the NKRP1A molecule is involved in transendothelial migration.

In this report, we show that among human CD4+ T lymphocytes 5-20% express the C-type lectin molecule NKRP1A. This lymphocyte subset displays a slightly more limited T cell receptor V beta repertoire than the CD4+ NKRP1A- counterpart. CD4+ NKRP1A+ T lymphocytes are characterized by a high expression of beta 1 and beta 2 integrins, thus representing a T lymphocyte subset that can possibly adhere and migrate through vascular endothelium. Indeed, resting CD4+ NKRP1A+ lymphocytes, differently from the CD4+ NKRP1A- subset, migrated across endothelial cell monolayers in a Transwell chamber system. Pretreatment of CD4+ NKRP1A+ T lymphocytes with an anti-NKRP1A monoclonal antibody (mAb) strongly reduced transendothelial migration, suggesting the involvement of the NKRP1A molecule in the transmigration process. Furthermore, cells of the NKRP1A- Jurkat CD4+ T cell line stably transfected with NKRP1A cDNA migrated more rapidly and efficiently than either untransfected or mock-transfected Jurkat cells. Finally, mAb-mediated cross-linking of NKRP1A molecules in CD4+ T lymphocytes induced the up-regulation of the lymphocyte function-associated antigen 1 Mg(2+)-binding site as well as beta 1 and beta 2 integrin chains. Altogether, these findings suggest that the NKRP1A molecule is involved in transendothelial migration of resting CD4+ T lymphocytes.

Antigens, Surface↗
PubMed1997

Expression and function of NKRP1A molecule on human monocytes and dendritic cells.

In this study, we analyzed the expression and function of the lymphocyte surface lectin NKRP1A on peripheral blood monocytes (Mo) or Mo and dendritic cells (DC) derived from thymic and bone marrow precursors. De novo expression of NKRP1A and CD14 molecules was detected upon culture of CD2- CD3- CD14- CD16- CD1a- NKRP1A- immature thymic precursors for 7 days in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF). Under these culture conditions, by day 21, a fraction of cells had lost CD14 and acquired both CD80 (B7.1) and CD86 (B7.2) molecules. These cells displayed a DC-like morphology and were surface NKRP1A positive. CD34+ NKRP1A- CD14- precursors, isolated from bone marrow and cultured in the presence of GM-CSF, also expressed both NKRP1A and CD14: these antigens were newly expressed on about one third of cells which had lost the CD34 precursor marker. In addition, NKRP1A was constitutively present on resting CD14+ peripheral blood Mo. When these cells were cultured in the presence of GM-CSF, the resulting DC population retained the expression of NKRP1A and acquired CD80, while they lost the CD14 antigen. Functional analysis revealed that the engagement of NKRP1A molecule leads to a strong intracellular calcium ([Ca2+]i) increase both in resting peripheral blood Mo and in vitro-derived DC. [Ca2+]i increase was mainly due to extracellular calcium influx, as it was completely abrogated by the addition of EGTA. More importantly, the engagement of the NKRP1A molecule induced interleukin (IL)-1 beta and IL-12 production by resting Mo and DC, respectively. Altogether these data indicate that NKRP1A lectin is present at the surface of Mo and DC and may play a relevant role in the activation and function of both cell types.

Antigens, Surface↗
PubMed1997

p40 molecule regulates NK cell activation mediated by NK receptors for HLA class I antigens and TCR-mediated triggering of T lymphocytes.

p40 was previously described as a regulatory molecule capable of inhibiting both the natural and the CD16-mediated cytotoxicity of NK cells. In this study, we analyze the effect of p40 molecule engagement on the NK cell triggering induced by activating HLA class I-specific NK receptors (NKR) or on TCR alpha beta-mediated T cell activation. CD3-CD16+ NK cell clones expressing activating NKR (either CD94 or p50) were analyzed in a redirected killing assay using P815 target cells and appropriate mAb. A strong target cell lysis was detected in the presence of anti-NKR or anti-CD16 mAb alone. Addition of anti-p40 mAb resulted in a strong inhibition of both anti-NKR or anti-CD16 mAb-induced cytolysis. mAb specific for either CD45 or lymphocyte function associated antigen-1 did not exert any inhibitory effect in the same experimental system. Free intracellular calcium ([Ca2+]i) increase induced by mAb cross-linking of activating CD94 or p50 was inhibited by simultaneous engagement of p40 molecules, but not of other NK surface molecules including CD44 and CD56. In addition, cross-linking of p40 molecules strongly inhibited the CD94-induced tumor necrosis factor-alpha and IFN-gamma production. Analysis of TCR alpha beta or gamma delta T cell clones revealed that the engagement of p40 molecules, using specific mAb, induced some degree of inhibition only on anti-V beta (but not anti-V delta or anti-CD3) mAb-induced cytotoxicity. On the other hand, the p40 molecule engagement prevented T cell proliferation induced by either anti-V beta 8 or anti-V delta 2 mAb. A similar inhibitory effect was found on the IL-2-induced NK cell proliferation. Taken together, our present findings suggest that p40 may play a role in the regulation of NK and T lymphocyte activation and proliferation.

Calcium↗
PubMed1997

The RGD-containing domain of exogenous HIV-1 Tat inhibits the engulfment of apoptotic bodies by dendritic cells.

OBJECTIVE: HIV-1 Tat can be released by infected cells and exert various extracellular functions on bystander cells, possibly contributing to immunodeficiency. In order to investigate whether exogenous Tat can affect antigen presentation, the effects of synthetic Tat on the function of dendritic cells displaying antigen presenting cell phenotype were studied. DESIGN: Cultured dendritic cells were challenged with apoptotic bodies and monitored for cell engulfment and free intracellular calcium ([Ca2+]i) increase. The effect of synthetic HIV-1 Tat and its RGD-containing domain (peptide 65-80) or basic domain (peptide 46-60) on both functions was investigated. METHODS: Dendritic cells were obtained by culture of monocytes with granulocyte-macrophage colony-stimulating factor. Apoptosis was induced in Jurkat cells by sub-lethal irradiation. Engulfment of radiolabelled apoptotic bodies by dendritic cells was obtained by a 45 min co-incubation at 37 degrees C. Non-ingested apoptotic bodies were removed and cell-associated radioactivity evaluated in a gamma-counter after cell lysis. Single cell analysis of calcium fluxes was performed by video-microscopy and ratio-imaging, after cell staining with the fluorescent calcium chelator FURA-2. RESULTS: Apoptotic bodies were engulfed by dendritic cells: this process was accompanied by [Ca2+]i rise. Synthetic HIV-1 Tat inhibited both apoptotic body engulfment and [Ca2+]i increase. The same inhibition was obtained with the RGD-containing domain (peptide 65-80), but not with the basic domain (peptide 46-60) of Tat, suggesting the involvement of an integrin. This integrin is likely to be alpha v beta 3, since RGD-containing peptides from vitronectin, but not from fibronectin, inhibited apoptotic body engulfment. Furthermore, both HIV-1 Tat and its 65-80 peptide blocked [Ca2+]i increase due to beta 3-integrin cross-linking. CONCLUSIONS: Our results support a role for HIV-1 Tat in decreasing the function of dendritic cells, possibly impairing antigen presentation.

Antigen Presentation↗
PubMed1997

Major histocompatibility complex class I-specific receptors on human natural killer and T lymphocytes.

Human NK cells express several specialized inhibitory receptors that recognize major histocompatibility complex (MHC) class I molecules expressed on normal cells. The lack of expression of one or more HLA class I alleles leads to NK-mediated target cell lysis. Receptors specific for groups of HLA-C (p58), HLA-B (p70) and HLA-A (p140) alleles belong to the Ig superfamily with two or three Ig-like domains in their extracellular portion, and a long cytoplasmic tail containing ITIM motifs and associated with a non-polar transmembrane portion. In contrast, the CD94/ NKG2-A receptor complex is composed of type II proteins with a C-type lectin domain which displays a more broad specificity for different class I alleles. Recently, activatory forms of the HLA-C-specific receptors have been identified in some donors. They are virtually identical to the inhibitory forms in their extracellular portions, but display a short cytoplasmic tail lacking ITIM motifs associated with a Lys-containing transmembrane portion (p50). A subset of activated T-lymphocytes, primarily CD8+ and oligoclonal or monoclonal in nature, express NK-type class I-specific receptors. These receptors exert an inhibitory activity on T-cell receptor-mediated functions and may provide an important mechanism of down-regulation of T-cell responses.

HLA Antigens↗
PubMed1996

IL2 triggers a tumor progression process in a melanoma cell line MELP derived from a patient whose metastasis increased in size during IL2/INFalpha biotherapy.

Human melanomas may express both in vivo and in vitro functional IL-Rs and may be expected to directly respond to injected IL2. This may generate biological situations which may be favourable for the patient, but also for tumor progression. Here, we analyse the latter hypothesis. MELP is a melanoma cell line derived from a patient whose metastasis increased in size during IL2/IFN alpha biotherapy [correction of biotheraphy]. These cells have been characterized in vitro for their phenotype and for their sensitivity to IL2. In vitro MELP cells express an IL2-R alpha(+) beta(+) gamma(-) phenotype and IL2 treatment induces the acquisition of new functional characteristics represented (i) by the increased surface expression of two markers of metastatic evolution (ICAM-1 and CD44); (ii) by the stable induction of the IL2-R gamma with the appearance of functional IL2-R beta complex, which are also recognized by GM-CSF; (iii) by the inhibition of transcription of a regulatory cytokine such as IL6; (iv) by a differential effect of IL6 on CD44 surface expression in MELP cells treated or not with IL2 (MILG cells); (v) by the acquisition of faster growth rates and appearance of piling up and multilayer cellular organization; (vi) by the development of rapidly growing tumors in nude mice. IL2 induces in MELP cells a tumor progression process that could mimic the metastatic evolution observed in vivo during biotherapy. Therefore, MELP phenotype may help to define a subset of patients in which IL2 therapy may trigger unfavourable evolution.

Adult↗
PubMed1996

The human leukocyte antigen (HLA)-C-specific "activatory" or "inhibitory" natural killer cell receptors display highly homologous extracellular domains but differ in their transmembrane and intracytoplasmic portions.

Natural killer cells express clonally distributed receptors specific for major histocompatibility complex class I molecules. The human leukocyte antigen (HLA)-C-specific receptors have been molecularly identified and cloned. They exist not only as inhibitory (p58) but also as activatory (p50) receptors. Here we show that p50 and p58 are highly homologous in their extracellular regions formed by two Ig-like domains. In contrast, major differences exist in their transmembrane and cytoplasmic portions. Whereas p 58 displays a 76-84-amino acid cytoplasmic tail containing an unusual antigen receptor activation motif, p50 is characterized by a shorter 39-amino acid tail. In addition, whereas p58 has a nonpolar transmembrane portion, p50 contains the charged amino acid Lys. These data strongly suggest that receptors with identical HLA-C allele specificity can mediate functions of opposite sign owing to their different transmembrane/cytoplasmic portions.

Amino Acid Sequence↗
PubMed1996

CD31-triggered rearrangement of the actin cytoskeleton in human natural killer cells.

In this report, we analyze whether CD31, also known as platelet-endothelial cell adhesion molecule-1 (PECAM-1), can transduce an outside-in signal in human natural killer (NK) lymphocytes in vitro. We show that CD31, but not HLA class-I cross-linking triggers an outside-in transmembrane signal in NK lymphocytes, mediating cell spreading and cytoskeletal rearrangement. These phenomena are Mg2+, but not Ca2+ dependent, suggesting that signal transduction elicited by CD31 cross-linking may involve an associated integrin. Two possible candidates would be alpha v and alpha L, whose function is known to depend on Mg2+. However, the CD31-induced cytoskeletal rearrangement was not reduced by the use of alpha v- or alpha L-specific F(ab')2, suggesting that CD31 could transduce a signal by itself or by association with a still-undefined integrin. Moreover, talin, but not vinculin or tubulin, appears to co-localize with actin microfilaments in the membrane ruffles of NK cells that undergo cytoskeleton rearrangement following CD31 cross-linking. Both spreading and cytoskeletal rearrangement appear to be regulated by intracellular cyclic-3',5'-adenosine monophosphate (cAMP). Indeed, the activator of the adenylyl cyclase, forskolin, inhibited cell spreading and cytoskeletal rearrangement induced by CD31 cross-linking. This phenomenon was also observed using the membrane-permeants cAMP analog Sp adenosine-3', 5' -cyclic monophosphothioate (Sp-cAMPS), but not its inactive isomer Rp-cAMPS. Likewise, adhesion of NK lymphocytes to NIH/3T3 murine fibroblasts transfected with the cDNA encoding human CD31 was blocked by increasing intracellular cAMPS levels. We suggest that intracellular cAMP may be involved in CD31-mediated signal transduction, and may regulate NK-endothelial cell adhesion and possibly, the tissue localization of NK cells.

3T3 Cells↗