bluuebunny/crossref_metadata_2025 huggingface dataset:
CHST1 and CHST2 sulfotransferase expression by vascular endothelial cells regulates shear-resistant leukocyte rolling vial-selectin
Authors: Li Xuan , Tu LiLi , Murphy Patricia G , Kadono Takafumi , Steeber Douglas A , Tedder Thomas F
Published: September 2022

Sulfation is an essential component of the selectin ligands, potentially mediated by members of a new family of carbohydrate sulfotransferases. In this study, we assessed the contributions of CHST1, CHST2, CHST3, and CHST4 in producing functional l-selectin ligands. Human umbilical vein endothelial cells predominantly expressed CHST1 and CHST2 transcripts with low levels of CHST3 mRNA, while cytokine activation up-regulated CHST2 expression and induced low-level CHST4 expression. A human umbilical vein endothelial cell line, EA.hy926, displayed functional l-selectin ligands that correlated with CHST1 and CHST2 expression in the absence of CHST4 expression. Increased CHST1 or CHST2 expression by a cell line expressing low-level l-selectin ligand activity during in vitro flow chamber assays increased rolling leukocyte numbers, reduced rolling velocities, and enhanced leukocyte rolling under higher shear stresses. These results suggest that CHST1 and CHST2 contribute to the generation of optimal l-selectin ligands in vascular endothelial cells at sites of inflammation.
The collagenous domain of class A scavenger receptors is involved in macrophage adhesion to collagens
Authors: Gowen Brian B , Borg Thomas K , Ghaffar Abdul , Mayer Eugene P
Published: September 2022

Class A macrophage scavenger receptors (MSRs) have a remarkably broadligand specificity and are well-known for their roles in atherogenesisand host defense. Recently, we demonstrated that these receptors alsorecognize and mediate adhesion to denatured forms of type I collagen. In this study, the involvement of the collagenous domain of MSRs inbinding to denatured type I collagen was investigated. Transientexpression of full-length, native type II MSR in COS-1 cells conferredadhesion to denatured type I collagens, whereas expression of atruncated receptor lacking the distal portion of the collagenous domaindid not. Further, a synthetic peptide derived from the collagenousdomain was effective in abrogating Mφ adhesion to denatured forms oftype I collagen. We also addressed collagen-type specificity byexamining MSR affinity for type III and type IV collagens. As with typeI collagen, Mφs adhered only to denatured forms of type III collagen.Moreover, the adhesion was mediated by MSRs. In contrast, adhesion todenatured type IV collagen was not shown to be MSR-dependent, butadhesion to the native form was. MSR-mediated adhesion to types III andIV collagens was also shown to be dependent on the collagenous domain.Taken together, these data strongly suggest that the collagenous domainis involved in MSR-mediated adhesion to denatured forms of types I andIII collagens and native, but not denatured, type IV collagen.
Transforming growth factor-β suppresses tumor necrosis factor α-induced matrix metalloproteinase-9 expression in monocytes
Authors: Vaday Gayle G , Schor Hagai , Rahat Michal A , Lahat Nitza , Lider Ofer
Published: September 2022

The inflammatory response is marked by the release of several cytokines with multiple roles in regulating leukocyte activities, including the secretion of matrix metalloproteinases (MMPs). Although the effects of individual cytokines on monocyte MMP expression have been studied extensively, few studies have examined the influence of combinations of cytokines, which are likely present at inflammatory sites. Herein, we report our investigation of the combinatorial effects of tumor necrosis factor (TNF)-α and transforming growth factor (TGF)-β on MMP-9 synthesis. We found that TGF-β suppressed TNF-α-induced MMP-9 secretion by MonoMac-6 monocytic cells in a dose-dependent manner, with a maximal effect of TGF-β observed at 1 ng/ml. Such suppression was likely regulated at the pretranslational level, because steady-state mRNA levels of TNF-α-induced MMP-9 were reduced by TGF-β, and pulse-chase radiolabeling also showed a decrease in new MMP-9 protein synthesis. The suppressive effects of TGF-β were time dependent, because short exposures to TNF-α before TGF-β or simultaneous exposure to both cytokines efficiently reduced MMP-9 secretion. Expression of the tissue inhibitor of metalloproteinases (TIMP)-1 and TNF-α receptors was unaffected by either cytokine individually or in combination. Affinity binding with radiolabeled TGF-β demonstrated that levels of TGF-β receptors were not increased after preincubation with TGF-β. Suppression of TNFα-induced MMP-9 secretion by TGF-β correlated with a reduction in prostaglandin E2 (PGE2) secretion. Furthermore, the effect of TGF-β or indomethacin on blockage of TNF-α-stimulated MMP-9 production was reversed by the addition of either exogenous PGE2 or the cyclic AMP (cAMP) analogue Bt2cAMP. Thus, we concluded that TGF-β acts as a potent suppressor of TNF-α-induced monocyte MMP-9 synthesis via a PGE2- and cAMP-dependent mechanism. These results suggest that various combinations of cytokines that are present at inflammatory sites, as well as their balance during different stages of inflammation, may provide the signals necessary for directing MMP-mediated leukocyte activities.
Expression of the apolipoprotein C-II gene during myelomonocytic differentiation of human leukemic cells
Authors: Chun Eun Mi , Park Young Jae , Kang Hong Soon , Cho Hyun Min , Jun Do Youn , Kim Young Ho
Published: September 2022

Apolipoprotein C-II (apoC-II), which is known to activate lipoprotein lipase (LPL), was identified by ordered differential display (ODD)-polymerase chain reaction (PCR) as a cDNA fragment exhibiting a distinct increase in expression during 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced differentiation of promonocytic U937 cells into monocytes and macrophages. The amount of apoC-II mRNA expression detectable in U937 cells significantly increased and reached a maximum 24–48 h after treatment with 32 nM TPA. apoC-II mRNA was also detected in monocytic THP-1 cells but was not detected in promyelocytic HL-60 cells. In healthy human tissues, the most significant expression of apoC-II mRNA was in the liver. Although apoC-II mRNA expression was markedly up-regulated during the induced differentiation of HL-60 cells into monocytes and macrophages with 32 nM TPA, such expression was not induced during the differentiation of HL-60 cells into granulocytes with 1.25% dimethyl sulfoxide. These results suggest that human apoC-II expression is induced at the transcription level during myelomonocytic differentiation and may confer an important role to macrophages involved in normal lipid metabolism and atherosclerosis.
Involvement of PKA, PKC, and Ca2+ in LPS-activated expression of the chicken lysozyme gene
Authors: Regenhard Petra , Goethe Ralph , Phi-van Loc
Published: September 2022

The lysozyme gene is activated in myelomonocytic HD11 cells in response to LPS. In this study, we described the involvement of LPS-activated signal transduction pathways in activation of the lysozyme gene. Pre-treatment of HD11 cells with H-89, H-7, TMB-8, or KN-93 resulted in inhibition of the LPS-enhanced lysozyme expression, suggesting that PKA, PKC, and Ca2+-dependent protein kinases participate in the LPS activation. CaMKII seems to be required for the processing of lysozyme transcripts. TPA and calcium ionophore A23187, when separately added to HD11 cells, stimulated the lysozyme expression effectively, and forskolin was ineffective. It is interesting that simultaneous treatment of cells with forskolin and calcium ionophore A23187 resulted in a potentiated increase in lysozyme mRNA expression, indicating a synergistic cooperation of PKA and Ca2+. This synergistic effect of PKA and Ca2+ was observed on the expression of a stably integrated CAT construct, controlled by the lysozyme promoter and the −6.1-kb enhancer containing binding sites for C/EBP and NF-κB/Rel. Therefore, we discussed the role of C/EBPβ(NF-M), CREB, and NF-κB/Rel as possible targets for phosphorylation mediated by PKA, PKC, and Ca2+.
Signal transduction pathways for activation of extracellular signal-regulated kinase by arachidonic acid in rat neutrophils
Authors: Chang Ling-Chu , Wang Jih-Pyang
Published: September 2022

Phosphorylation of extracellular signal-regulated kinase (ERK) inresponse to arachidonic acid (AA) was rapid and transient, peaking at 1min and disappearing after 3 min, and it was accompanied by an increasein ERK activity in rat neutrophils. We examined the upstream regulationof AA-stimulated ERK activation using one of the following signalingpathway inhibitors to pretreat rat cells: the ERK kinase inhibitorU0126 or PD98059, the Gi/o inhibitor pertussis toxin (PTX),the tyrosine kinase inhibitor genistein, the phosphatidylinositol3-kinase (PI3K) inhibitor wortmannin or LY294002, the Ca2+chelator 1,2-bis(O-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid, or the phospholipase C(PLC) inhibitor U73122. All of these inhibitors attenuated AA-inducedERK activation. Activation of ERK was also effectively attenuated bythe cyclooxygenase and lipoxygenase inhibitor BW755C and by theleukotriene biosynthesis inhibitor MK886, but the cyclooxygenaseinhibitor indomethacin did not attenuate ERK activation. After exposingcells to three distinct protein kinase C (PKC) inhibitors, we foundthat Gö6976 significantly attenuated ERK phosphorylation butpotentiated ERK activity. Neither Gö6983 nor GF109203Xaffected AA-induced responses. These data suggest that the lipoxygenasemetabolite(s) produced mediates AA-stimulated ERK activation and thatthis effect is upstream regulated by PT-sensitive G protein,nonreceptor tyrosine kinase, PI3K, and PLC/Ca2+ signalingpathways in rat neutrophils.
Analysis of macrophage activation in African trypanosomiasis
Authors: Paulnock Donna M , Coller Susan P
Published: September 2022

African trypanosomes cause a fatal disease of man and animals that ischaracterized by extensive functional, histological, and pathologicalchanges in the lymphoid tissues of infected hosts, including anincrease in the numbers and activation state of macrophages. Macrophageactivation during infection is the result of exposure of these cells toparasite components and host-derived IFN-γ, produced in response toparasite antigens. The balance of these different activation signalsmay determine the outcome of infection. In the experiments describedhere, we assessed the ability of the variant surface glycoprotein (VSG)of the organism Trypanosoma brucei rhodesiense (T.b.rhodesiense) to activate macrophages directly. Our resultsdemonstrate that macrophages bind and are activated by the VSGmolecule. The resulting profile of activation differs from thatstimulated by IFN-γ. These results suggest that the interaction ofhost macrophages with VSG released during parasite infection may be akey component of trypanosomiasis.
Participation of mammalian defensins and cathelicidins in anti-microbial immunity: receptors and activities of human defensins and cathelicidin (LL-37)
Authors: Yang De , Chertov Oleg , Oppenheim Joost J
Published: September 2022

Defensins and cathelicidins are the two major families of mammalian anti-microbial proteins. They contribute to host, innate, anti-microbial defense by disrupting the integrity of the bacterial cell membrane. However, several members of the mammalian anti-microbial proteins including defensins and cathelicidins have been shown recently to have chemotactic effects on host cells. Human neutrophil α-defensins are chemotactic for resting, naïve CD45RA/CD4 T cells, CD8 T cells, and immature dendritic cells. Human β-defensins are also chemotactic for immature dendritic cells but induce the migration of memory CD45RO/CD4 T cells. In contrast, cathelicidin/LL-37 is chemotactic for neutrophils, monocytes, and T cells but not for dendritic cells. Thus, these anti-microbial peptides have distinct, host-target cell spectra. The chemotactic activities of human β-defensins and cathelicidin/LL-37 are mediated by human CC chemokine receptor 6 and formyl peptide receptor-like 1, respectively. The capacities of defensins and cathelicidins to mobilize various types of phagocytic leukocytes, immature dendritic cells, and lymphocytes, together with their other effects such as stimulating IL-8 production and mast cell degranulation, provide evidence for their participation in alerting, mobilizing, and amplifying innate and adaptive anti-microbial immunity of the host.
In vivo roles of donor and host dendritic cells in allogeneic immune response: cluster formation with host proliferating T cells
Authors: Saiki Takahito , Ezaki Taichi , Ogawa Michio , Maeda Keiko , Yagita Hideo , Matsuno Kenjiro
Published: September 2022

Possible roles of dendritic cells (DCs) in allogeneic immune responses in host lymphoid tissues were characterized in situ by using rat DC transfer and cardiac transplantation models. When allogeneic DCs were intravenously injected, these cells selectively migrated to the T-cell area of hepatic lymph nodes, with peak accumulation at 18 h after injection. Donor DCs and proliferating host T cells formed clusters (rosettes) in which the T-cell proliferative response started. The donor DCs were CD80+ CD86+ and, ultrastructurally, were in intimate contact with lymphoblasts within the rosettes. As a novel finding, some of the migrated donor DCs were quickly phagocytosed by putative host interdigitating DCs. By 48 h, the remaining donor DCs had disintegrated within the rosettes. Host interdigitating DCs also formed rosettes throughout the T-cell area, and their kinetics correlated well with that of the T-cell proliferation. In the cardiac allograft model, a few donor DCs selectively migrated to the host spleen and hepatic nodes. Rosette formation by donor and host DCs, phagocytosis of donor DCs, and the T-cell proliferative response occurred in much the same fashion as they did in the first experiment. We conclude that the donor rosettes at the early stage represent the sites of direct allosensitization and those at the late stage represent donor-DC killing. Host rosettes are the sites of T-cell proliferation. In this structure, phagocytosed donor-DC-derived antigens are presumably indirectly presented.
CD1d-reactive T-cell activation leads to amelioration of disease caused by diabetogenic encephalomyocarditis virus
Authors: Exley Mark A , Bigley Nancy J , Cheng Olivia , Tahir Syed Muhammad Ali , Smiley Stephen T , Carter Quincy L , Stills Harold F , Grusby Michael J , Koezuka Yasuhiko , Taniguchi Masuru , Balk Steven P
Published: September 2022

A subset of CD161 (NK1) T cells express an invariant Vα14Jα281TCR-α chain (Vαinvt T cells) and produce Th2 and Th1cytokines rapidly in response to CD1d, but their physiologicalfunction(s) remain unclear. We have found that CD1d-reactive T cellsmediate to resistance against the acute, cytopathic virus diabetogenicencephalomyocarditis virus (EMCV-D) in relatively Th1-biased,C57BL/6-based backgrounds. We show now that these results generalize toTh2-biased, hypersensitive BALB/c mice. CD1d-KO BALB/c mice were moresusceptible to EMCV-D. Furthermore, α-galactosylceramide(α-GalCer), a CD1d-presented lipid antigen that specificallyactivates Vαinvt T cells, protected wild-type (WT) miceagainst EMCV-D-induced encephalitis, myocarditis, and diabetes. Incontrast, neither CD1d-KO nor Jα281-KO mice were protected byα-GalCer. Finally, disease in Jα281-KO mice was comparable to WT, indicating for the first time equivalent roles for CD1d-reactiveVαinvt and noninvariant T cells in resistance to acuteviral infection. A model for how CD1d-reactive T cells can initiateimmune responses, which synthesizes current results, ispresented.
Mixed allogeneic chimerism with wild-type strains ameliorates atherosclerosis in apolipoprotein E-deficient mice
Authors: Ishimori Naoki , Iwabuchi Kazuya , Fujii Satoshi , Watano Keiko , Iwabuchi Chikako , Ato Manabu , Chiba Hitoshi , Tanaka Shinya , Kitabatake Akira , Onoé Kazunori
Published: September 2022

Atherosclerosis involves inflammatory processes between vasculartissues and hematocytes with a hyperlipidemic background. To examinewhether variations of hematocytes constitute one of the geneticcomponents in atherosclerosis, irradiated apolipoprotein E(apoE)-deficient (apoE−/−) mice with hypercholesterolemiaand preexisting atherosclerotic lesions were reconstituted withmixed bone marrow cells (BMC) from syngeneic and wild-type(apoE+/+; atherosclerosis-resistant SJL or -susceptibleB10.S) mice. Stable mixed allogeneic chimeras with small amounts ofserum apoE were established without any detrimentalcomplications. Compared with untreated apoE−/− miceor apoE−/− mice transplanted with syngeneic BMC alone, significant reduction of the cholesterol level and significant lesionregression were observed in the mixed chimeras. Furthermore, mixedchimeras given SJL BMC showed marked reductions in numbers of lesionscompared with those reconstituted with B10.S BMC. Cholesterol levels inthe former SJL chimeras, however, were significantly higher than thosein the latter B10.S chimeras. These findings indicate that theresistance of SJL to atherosclerosis resides in the bone marrow-derivedcells.
Blood mononuclear cells induce regulatory NK T thymocytes in anterior chamber-associated immune deviation
Authors: Wang Yafei , Goldschneider Irving , O'Rourke James , Cone Robert E
Published: September 2022

Injection of antigen into the anterior chamber (AC) of the eye, animmunologically privileged site, is associated with the inductionof immune deviation, as evidenced by T helper cell (Th) 1 to Th2 cellpolarization. We recently demonstrated that AC-associated immunedeviation (ACAID) is a thymus-dependent phenomenon initiated by the formation of regulatory α,β T-cell receptor-positiveCD4− CD8− thymocytes(THYregs). In this study, the afferent and efferent limbsof this immunoregulatory loop were traced from peripheral blood to thethymus and then to the spleen by adoptive-transfer assays. The resultsdemonstrate that (1) F4/80+ CD1+ peripheralblood mononuclear cells from mice whose ACs were injected withtrinitrophenol-bovine serum albumin induce the appearance ofnatural killer (NK) 1.1+ THYreg innaïve recipients within 24 h of intravenous infusion; (2)these NK THYregs induce (or generate) suppressor-effector Tcells in the spleens of adoptive recipients; (3) thesesuppressor-effector spleen cells, but not the NK THYregsthemselves, directly inhibit the expression of delayed-typehypersensitivity in sensitized recipients; and (4) peripheral bloodmononuclear cells from AC-injected mice do not induce ACAID inthymectomized recipients. These results confirm our hypothesis thatACAID is a model of centrally induced dominant tolerance mediated byCD-1-dependent NK T cells of recent thymic origin. The results alsoprovide evidence of a novel tolerance induction pathway by whichblood-borne antigen-presenting cells generated by antigen injectioninto an immunologically privileged site transport antigen to the thymusand induce the formation and export of THYreg.
Eotaxin promotes eosinophil transmigration via the activation of the plasminogen-plasmin system
Authors: Ferland Claudine , Guilbert Martin , Davoine Francis , Flamand Nicolas , Chakir Jamila , Laviolette Michel
Published: September 2022

The effect of eotaxin, a potent eosinophil chemotactic factor, on eosinophil transmigration through a reconstituted basal membrane (Matrigel®) was evaluated. Eotaxin induced significant eosinophil transmigration in the presence of 10% fetal bovine serum (FBS) and interleukin-5. Its effect was optimal at 0.01 μM, and it plateaued at 18 h. Eotaxin's effect was greater with eosinophils from asthmatic subjects (61.1 ± 3.4%) than with eosinophils from normal subjects (38.7 ± 4.2%) (P < 0.001). Inhibition of metalloproteinases decreased eotaxin-induced transmigration by ≤10.4%, whereas inhibition of the plasminogen-plasmin system decreased eotaxin's effect by ≤44.4% (P = 0.0002). Moreover, eotaxin-induced transmigration was largely diminished in medium with low concentrations of serum [0.5% FBS: 6.1 ± 2.4%; 10% FBS: 40.2 ± 5.8% (P = 0.0001)] but returned to its initial level with the addition of plasminogen (2 U/mL) to 0.5% FBS (43.1 ± 6.5%). These data show that eotaxin is an efficient promoter of eosinophil transmigration in vitro, that it is more potent with cells from asthmatics than with normal cells, and that its effect depends predominantly on the activation of the plasminogen-plasmin system.
Modulation of death receptor-mediated apoptosis in differentiating human myeloid leukemia HL-60 cells
Authors: Vondráček Jan , Sheard Michael A , Krejčí Pavel , Minksová Kateřina , Hofmanová Jiřina , Kozubík Alois
Published: September 2022

Differentiating myeloid cells may become resistant to various apoptotic stimuli. In the present study, dimethyl sulfoxide (DMSO) and all-trans retinoic acid (ATRA) were found to modulate the sensitivity of HL-60 cells to death receptor-mediated apoptosis in a time-dependent manner. During the early stages of differentiation, DMSO treatment increased the response of HL-60 cells to tumor necrosis factor α; (TNF-α), but enhanced responsiveness was lost during later differentiation stages. In contrast, ATRA treatment induced resistance to TNF-α-induced apoptosis. HL-60 cells were resistant to Fas-mediated apoptosis but were sensitized by culturing in serum-free conditions. Similar to its effect on TNF-α sensitivity, DMSO pretreatment augmented the response to Fas-mediated signaling, which coincided with increased expression of Fas on DMSO-pretreated cells. However, during the later stages of DMSO-induced differentiation, sensitivity to anti-Fas antibody-induced apoptosis declined significantly, although Fas expression was still elevated. The reduced sensitivity to anti-Fas treatment partially correlated with increased Fas-associated phosphatase-1 mRNA expression. Thus, regardless of either Fas up-regulation or potentiation of TNF-α-mediated apoptosis during early DMSO-induced differentiation, a slow increase in resistance to apoptosis mediated through these death receptors occurs during DMSO-induced differentiation, which contrasts with the rapid induction of resistance following treatment with ATRA.
Role of mitogen-activated protein kinases in the differential regulation of interleukin-2 by cannabinol
Authors: Jan Tong-Rong , Kaminski Norbert E
Published: September 2022

Cannabinoids can paradoxically regulate interleukin-2 (IL-2) expressioneither positively or negatively. This study investigated the mechanismresponsible for cannabinol-mediated IL-2 modulation. In primary murinesplenocytes and EL4.IL-2 T cells, the contrasting effects of cannabinolon IL-2 secretion depended on the magnitude but not the mode of T-cellactivation. Suboptimal activation of T cells in the presence ofcannabinol produced an enhancement of IL-2 secretion, which wasparalleled by an increase in nuclear phospho-extracellular-regulatedkinase (ERK) 1/2. In contrast, T cells activated with stimulithat were optimized to induce maximal IL-2 secretion elicited a markedsuppression in the production of this cytokine when cultured in thepresence of cannabinol. Moreover, cannabinol-mediated enhancement of IL-2 secretion by splenocytes was attenuated to various degrees bystaurosporine, Ro-31-8220, and KN93. These results suggest that theenhancement of IL-2 secretion by cannabinol is associated with anincrease in ERK mitogen-activated protein kinase, which is proteinkinase C and calmodulin-kinase dependent.
Identification and characterization of human eosinophil cationic protein by an epitope-specific antibody
Authors: Boix Ester , Carreras Esther , Nikolovski Zoran , Cuchillo Claudi M , Nogués M Victòria
Published: September 2022

The eosinophil cationic protein (ECP) is a basic secretion proteininvolved in the immune response system. ECP levels in biological fluidsare an indicator of eosinophil-specific activation and degranulationand are currently used for the clinical monitoring and diagnosis ofinflammatory disorders. A polyclonal epitope-specific antibody has beenobtained by immunizing rabbits with a conjugated synthetic peptide. Asequence corresponding to a large exposed loop in the human ECPthree-dimensional structure (D115–Y122) was selected as a putativeantigenic epitope. The antibody was purified on an affinity columnusing recombinant ECP (rECP) as antigen. The antibody (D112–P123 Ab)specifically recognizes rECP and its native glycosylated andnonglycosylated forms in plasma, granulocytes, and sputum. The antibodydetects as little as 1 ng of rECP, can be used both in reducing andnonreducing conditions, and does not cross-react with the highlyhomologous eosinophil-derived neurotoxin or other proteins of thepancreatic ribonuclease superfamily.
Suppression of T-cell responsiveness by inducible cAMP early repressor (ICER)
Authors: Bodor Josef , Feigenbaum Lionel , Bodorova Jana , Bare Cathy , Reitz Marvin S , Gress Ronald E
Published: September 2022

Depending on the nature of the costimulation of T lymphocytes, expression of regulatory cytokines and chemokines is either susceptibleor resistant to cyclic AMP (cAMP)-mediated inhibition. Our data showthat cAMP-mediated inhibition of endogenously expressed cytokines, which is characteristic for T helper (Th) 1- and Th 2-like phenotypes, correlates with the induction of a potent transcriptional repressor, inducible cAMP early repressor (ICER), in both subsets of T cellsactivated under conditions of suboptimal interleukin-2 (IL-2)expression. Importantly, Th-specific expression of certain chemokinesis also susceptible to cAMP-mediated transcriptional attenuation. Todetermine whether ICER per se, rather than forskolin-mediated elevationof intracellular cAMP, is responsible for the observed inhibitoryeffect, we generated transgenic mice expressing ICER under the controlof a lymphocyte-specific lck promoter. On stimulation, transgenic thymocytes overexpressing ICER exhibited reduced levels of IL-2 and interferon (IFN)-γ and failed to express the macrophageinflammatory protein (MIP)-1α and MIP-1β genes. Splenic T cellsfrom ICER-transgenic mice showed a defect in proliferation and lacked amixed lymphocyte reaction response, implying that ICER-mediatedinhibition of cytokine and chemokine expression might play an importantrole in T-cell inactivation.
Gelatinase B functions as regulator and effector in leukocyte biology
Authors: Opdenakker Ghislain , Van den Steen Philippe E , Dubois Bénédicte , Nelissen Inge , Van Coillie Els , Masure Stefan , Proost Paul , Van Damme Jo
Published: September 2022

Matrix metalloproteinases (MMPs) form a family of enzymes with major actions in the remodeling of extracellular matrix (ECM) components. Gelatinase B (MMP-9) is the most complex family member in terms of domain structure and regulation of its activity. Gelatinase B activity is under strict control at various levels: transcription of the gene by cytokines and cellular interactions; activation of the pro-enzyme by a cascade of enzymes comprising serine proteases and other MMPs; and regulation by specific tissue inhibitors of MMPs (TIMPs) or by unspecific inhibitors, such as α2-macroglobulin. Thus, remodeling ECM is the result of the local protease load, i.e., the net balance between enzymes and inhibitors. Glycosylation has a limited effect on the net activity of gelatinase B, and in contrast to the all-or-none effect of enzyme activation or inhibition, it results in a higher-level, fine-tuning effect on the ECM catalysis by proteases in mammalian species. Fast degranulation of considerable amounts of intracellularly stored gelatinase B from neutrophils, induced by various types of chemotactic factors, is another level of control of activity. Neutrophils are first-line defense leukocytes and do not produce gelatinase A or TIMP. Thus, neutrophils contrast sharply with mononuclear leukocytes, which produce gelatinase A constitutively, synthesize gelatinase B de novo after adequate triggering, and overproduce TIMP-1. Gelatinase B is also endowed with functions other than cleaving the ECM. It has been shown to generate autoimmune neo-epitopes and to activate pro-IL-1β into active IL-1β. Gelatinase B ablation in the mouse leads to altered bone remodeling and subfertility, results in resistance to several induced inflammatory or autoimmune pathologies, and indicates that the enzyme plays a crucial role in development and angiogenesis. The major human neutrophil chemoattractant, IL-8, stimulates fast degranulation of gelatinase B from neutrophils. Gelatinase B is also found to function as a regulator of neutrophil biology and to truncate IL-8 at the aminoterminus into a tenfold more potent chemokine, resulting in an important positive feedback loop for neutrophil activation and chemotaxis. The CXC chemokines GRO-α, CTAP-III, and PF-4 are degraded by gelatinase B, whereas the CC chemokines MCP-2 and RANTES are not cleaved.
Agonistic and antagonistic activities of chemokines
Authors: Loetscher Pius , Clark-Lewis Ian
Published: September 2022

Since the discovery of interleukin-8, about 50 chemokines have been identified and characterized. Originally, they were considered as inducible mediators of inflammation, but in recent years, several chemokines were identified that are expressed constitutively and function in physiological traffic and homing of leukocyte—lymphocytes in particular. All chemokines act via seven-transmembrane domain, G protein-coupled receptors. Eighteen such receptors have been identified so far. Studies on structure-activity relationships indicate that chemokines have two main sites of interaction with their receptors, the flexible NH2-terminal region and the conformationally rigid loop that follows the second cysteine. Chemokines are thought to dock onto receptors by means of the loop region, and this contact is believed to facilitate the binding of the NH2-terminal region that results in receptor activation. These studies have also highlighted the importance of the NH2-terminal region for agonistic and antagonistic activity. Recently, we have shown that some naturally occurring chemokines can function as receptor antagonists. These observations suggest a new mechanism for the regulation of leukocyte recruitment during inflammatory and immune reactions, which are based on the combination of agonistic and antagonistic effects.
Control of chromatin accessibility for V(D)J recombination by interleukin-7
Authors: Huang Jiaqiang , Muegge Kathrin
Published: September 2022

IL-7 is a key factor for lymphoid development, and it contributes to V(D)J recombination at multiple loci in immune-receptor genes. IL-7 signal transduction, involving γc and Jak3, is required for successful recombination at the TCR-γ locus. IL-7 signaling controls the initiation phase of V(D)J recombination by controlling access of the V(D)J recombinase to the locus. In the absence of IL-7, the TCR-γ locus is methylated and packaged in a repressed form of chromatin consisting of hypoacetylated histones. IL-7 signaling likely increases the acetylation state of the nucleosomal core histones resulting in an “open” form of chromatin. This opening leads to a higher accessibility for the transcription machinery and increased accessibility of the Rag heterodimer that performs the cleavage of DNA.
Functional classification of interferon-stimulated genes identified using microarrays
Authors: de Veer Michael J , Holko Michelle , Frevel Mathias , Walker Eldon , Der Sandy , Paranjape Jayashree M , Silverman Robert H , Williams Bryan R G
Published: September 2022

Interferons (IFNs) are a family of multifunctional cytokines thatactivate transcription of subsets of genes. The gene products inducedby IFNs are responsible for IFN antiviral, antiproliferative, andimmunomodulatory properties. To obtain a more comprehensive list and abetter understanding of the genes regulated by IFNs, we compiled datafrom many experiments, using two different microarray formats. Thecombined data sets identified >300 IFN-stimulated genes (ISGs). Toprovide new insight into IFN-induced cellular phenotypes, we assignedthese ISGs to functional categories. The data are accessible on the World Wide Web at http://www.lerner.ccf.org/labs/williams, including functional categories and individual genes listed in asearchable database. The entries are linked to GenBank and Unigenesequence information and other resources. The goal is to eventuallycompile a comprehensive list of all ISGs. Recognition of the functionsof the ISGs and their specific roles in the biological effects of IFNsis leading to a greater appreciation of the many facets of theseintriguing and essential cytokines. This review focuses on thefunctions of the ISGs identified by analyzing the microarray data andfocuses particularly on new insights into the protein kinaseRNA-regulated (PRKR) protein, which have been made possible with theavailability of PRKR-null mice.
Transient expansion of peptide-specific lymphocytes producing IFN-γ after vaccination with dendritic cells pulsed with MAGE peptides in patients with mage-A1/A3-positive tumors
Authors: Toungouz M , Libin M , Bulté F , Faid L , Lehmann F , Duriau D , Laporte M , Gangji D , Bruyns C , Lambermont M , Goldman M , Velu T
Published: September 2022

Assessment of T-cell activation is pivotal for evaluation of cancerimmunotherapy. We initiated a clinical trial in patients with MAGE-A1and/or -A3 tumors using autologous DC pulsed with MAGE peptides aimedat analyzing T-cell-derived, IFN-γ secretion by cytokine flowcytometry and ELISPOT. We also tested whether further KLH additioncould influence this response favorably. Monocyte-derived DC weregenerated from leukapheresis products. They were pulsed with therelevant MAGE peptide(s) alone in group A (n=10 pts) andadditionally with KLH in group B (n=16 pts). A specific buttransient increase in the number of peripheral blood T lymphocytessecreting IFN-γ in response to the vaccine peptide(s) was observed in6/8 patients of group A and in 6/16 patients of group B. We concludethat anti-tumor vaccination using DC pulsed with MAGE peptides inducesa potent but transient anti-MAGE, IFN-γ secretion that is notinfluenced by the additional delivery of a nonspecific, T-cellhelp.
The search for new vaccines against tuberculosis
Authors: Orme Ian M
Published: September 2022

The failure of the BCG vaccine for tuberculosis in large, controlledclinical trials, coupled with the gradual consensus that it is mostlyineffective in preventing adult pulmonary disease in endemic areas, hasled to a concerted effort to develop a new generation of vaccines. Thiswork is ongoing in a variety of areas, including DNA vaccines, subunitvaccines, recombinant vaccines, and auxotrophic vaccines. Several suchcandidates are giving promising results in mouse and guinea pig,aerosol-challenge infection models and should move to clinical trialsin the near future.
Surfactant protein D-coatedKlebsiella pneumoniaestimulates cytokine production in mononuclear phagocytes
Authors: Keisari Yona , Wang Hongbin , Mesika Adi , Matatov Robert , Nissimov Liat , Crouch Erika , Ofek Itzhak
Published: September 2022

Encapsulated Klebsiella pneumoniae strains K21a, K10, and K50, all of which contain dimannose sequences in their capsular polysaccharides that are recognized by the mannose receptor of macrophages, stimulated interleukin secretion and cytokine mRNA expression by human monocyte-derived macrophages. By contrast, the corresponding unencapsulated phase variants and the K2 strain, which lack the dimannose sequence, did not. Coating of unencapsulated phase variants of Klebsiella strains with surfactant protein (SP)-D resulted in marked stimulation of cytokine mRNA accumulation. The induction of cytokine mRNA via the mannose receptor occurred only in monocyte-derived macrophages, whereas that caused by SP-D-coated Klebsiella strains occurred in both macrophages and peripheral-blood monocytes.The results suggested that innate immunity against pulmonary pathogens might be mediated by SP-D, which acts as an opsonin to enhance the interaction of macrophages with unencapsulated phase variants originating from the upper respiratory tract, and by macrophage mannose receptors, which recognize encapsulated variants expressing capsular dimannose residues.
Synthetic peptide MMK-1 is a highly specific chemotactic agonist for leukocyte FPRL1
Authors: Hu Jin Yue , Le Yingying , Gong Wanghua , Dunlop Nancy M , Gao Ji Liang , Murphy Philip M , Wang Ji Ming
Published: September 2022

Human phagocytic leukocytes express the seven-transmembraneG-protein-coupled receptors formyl peptide receptor (FPR) and FPR-like1 (FPRL1). MMK-1, a synthetic peptide derived from a random peptidelibrary, is reported to induce calcium mobilization specifically inhuman FPRL1 gene-transfected cells. However, its actions onhuman phagocytic leukocytes remain poorly defined. We found that MMK-1is a potent chemotactic and calcium-mobilizing agonist for humanmonocytes, neutrophils, and FPRL1-transfected human embryonic kidney(HEK) 293 cells but is inactive in cells transfected with FPR. MMK-1also activated HEK 293 cells transfected with FPR2, a mousecounterpart of human FPRL1. Furthermore, MMK-1 increasedpertussis toxin-sensitive production of inflammatory cytokines in humanmonocytes. MMK-1 signaling in human phagocytes was completelydesensitized by a well-defined FPRL1 agonist, suggesting thatFPRL1 is likely a receptor that mediates the action of MMK-1 in primarycells. Since MMK-1 is one of the most potent FPRL1-specific agonistsidentified so far, it can serve as a modulator of the hostdefense and a useful agent for further studying the signaling andfunction of FPRL1.
Unlocking the secrets of cytotoxic granule proteins
Authors: Smyth Mark J , Kelly Janice M , Sutton Vivien R , Davis Joanne E , Browne Kylie A , Sayers Thomas J , Trapani Joseph A
Published: September 2022

Cytotoxic lymphocytes largely comprise CD8+ cytotoxic T cells and natural killer cells and form the major defense of higher organisms against virus-infected and transformed cells. A key function of cytotoxic lymphocytes is to detect and eliminate potentially harmful cells by inducing them to undergo apoptosis. This is achieved through two principal pathways, both of which require direct but transient contact between the killer cell and its target. The first, involving ligation of TNF receptor-like molecules such as Fas/CD95 by their cognate ligands, results in mobilization of conventional, programmed cell-death pathways centered on activation of pro-apoptotic caspases. This review concentrates on the second pathway, in which the toxic contents of secretory vesicles of the cytotoxic lymphocyte are secreted toward the target cell, and some toxins penetrate into the target cell cytoplasm and nucleus. In addition to invoking a powerful stimulus to caspase activation, this “granule-exocytosis mechanism” provides a variety of additional strategies for overcoming inhibitors of the caspase cascade that may be elaborated by viruses. The key molecular players in this process are the pore-forming protein perforin and a family of granule-bound serine proteases or granzymes. The molecular functions of perforin and granzymes are under intense investigation in many laboratories including our own, and recent advances will be discussed. In addition, this review discusses the evidence pointing to the importance of perforin and granzyme function in pathophysiological situations as diverse as infection with intracellular pathogens, graft versus host disease, susceptibility to transplantable and spontaneous malignancies, lymphoid homeostasis, and the tendency to auto-immune diseases.
Long-term-impaired expression of nuclear factor-κB and IκBα in peripheral blood mononuclear cells of trauma patients
Authors: Adib-Conquy Minou , Asehnoune Karim , Moine Pierre , Cavaillon Jean-Marc
Published: September 2022

Nuclear factor (NF)-κB expression and dimer characteristics were studied in peripheral blood mononuclear cells (PBMCs) of major-trauma patients and healthy controls. Analysis of PBMCs on days 1, 3, 5, and 10 after trauma revealed that expression of both p65p50 heterodimers and p50p50 homodimers was significantly reduced compared with that in controls. In vitro lipopolysaccharide (LPS) stimulation of PBMCs induced NF-κB translocation. However, throughout the survey, p65p50 activation remained significantly lower in trauma patients than in controls. After LPS stimulation in vitro, the p65p50/p50p50 ratio was significantly lower in PBMCs from trauma patients than from healthy controls. The ex vivo expression of IκBα was higher in PBMCs of controls than of trauma patients. LPS did not induce IκB expression in PBMCs from trauma patients, but strong induction was obtained with staphylococci, suggesting that this defect is not universal and depends on the nature of the activating signal. Although no direct correlation was found between levels of interleukin-10 or transforming growth factor-β and NF-κB, these immunosuppressive cytokines were significantly elevated in trauma patients by 10 days after admission. The long-term low-basal and LPS-induced nuclear translocation of NF-κB recalled long-term immunoparalysis observed in patients with severe inflammatory stress such as trauma.
Dimeric S100A8 in human neutrophils is diminished after phagocytosis
Authors: Kumar Rakesh K , Yang Zheng , Bilson Susan , Thliveris Soula , Cooke Bridget E , Geczy Carolyn L
Published: September 2022

S100A8 is a major cytoplasmic protein of neutrophils andmonocytes/macrophages and has been associated with myeloid celldifferentiation and activation. Little is known about its functions ormechanisms of release from neutrophils. We have developed a monoclonalantibody to murine S100A8, which cross-reacts with human S100A8. Thisantibody, which recognizes the homodimeric form of the protein, detectsits expression specifically in human neutrophils and is reactive informalin-fixed, paraffin-embedded tissues. Using this antibody as wellas a commercially available antibody to human S100A8, we show thatphagocytic activation of neutrophils, in vivo in acuteappendicitis and in vitro following phagocytosis ofopsonized zymosan, is characterized by loss of cytoplasmicimmunoreactivity for S100A8. In vitro, phagocytosis isassociated with rapid diminution of immunostaining without loss ofviability. Loss of immunoreactivity for S100A8 may serve as a marker oflocalized neutrophil activation in tissues.
Leukocyte recruitment at sites of tumor: dissonant orchestration
Authors: Carlos T M
Published: September 2022

Biopsies of tumors responding to interleukin 2 (IL-2) based immunotherapy have been reported to show a leukocytic infiltration. Clinical responses to IL-2-based immunotherapy, however, are limited, suggesting a failure of leukocyte localization at tumor sites. Leukocyte infiltration at inflammatory sites requires local activation of leukocytes and endothelial cells in a coordinated and defined temporal sequence. There is evidence supporting the theory that infiltration of leukocytes at tumor sites is suboptimal due to a failure of coordination of these localizing events. In this review, factors involved in leukocyte recruitment at sites of inflammation and the coordination of these factors in a successful model of inflammation, i.e., wound healing, are discussed. This example is contrasted with events at tumor sites where alterations in expression of cell adhesion molecules or in the production of activating agents may be present. Additionally, the systemic administration of an activating cytokine such as IL-2 may fail to duplicate events that normally occur within a local environment. These observations may facilitate the design of future immunotherapy trials.
IL-1 and TNF independent pathways mediate ICAM-1/VCAM-1 up-regulation in ischemia reperfusion injury
Authors: Burne Melissa J , Elghandour Asmaa , Haq Mahmud , Saba Sabiha R , Norman James , Condon Thomas , Bennett Frank , Rabb Hamid
Published: September 2022

In vitro studies have suggested that targeting interleukin (IL)-1 and tumor necrosis factor (TNF) can be used to regulate intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) and potentially treat kidney inflammation. We therefore evaluated ICAM-1 and VCAM-1 regulation in knockout (KO) mice deficient in both IL-1 receptor 1 (R1) and TNF-R1 during renal ischemia reperfusion injury. ICAM-1 and VCAM-1 mRNA expression was measured with specific murine probes and Northern blotting (n =4/group). Protein expression was measured using immunohistochemistry. Serum creatinine (SCr), tubular histology, and neutrophil infiltration into postischemic kidneys were also quantified. ICAM-1 and VCAM-1 mRNA expression increased in both wild-type (WT) and KO mice at 2, 6, and 24 h. Protein expression of ICAM-1 and VCAM-1 was also increased at 24 h postischemia. SCr levels and tubular necrosis scores were comparable in WT and KO mice at 24 and 48 h. Neutrophil migration in KO mice was decreased at 24 h but comparable to WT at 48 h. These data demonstrate that IL-1 and TNF are not essential for postischemic increases in ICAM-1 and VCAM-1.
IgE-regulated loss, not IgE-regulated synthesis, controls expression of FcɛRI in human basophils
Authors: MacGlashan Donald , Xia Han-Zhang , Schwartz Lawrence B , Gong Jianping
Published: September 2022

Expression of the high-affinity receptor on basophils and mast cells is modulated by immunoglobulin E (IgE) antibody. Recent studies have shown that modulation occurs through interaction of IgE with the receptor itself, but the mechanisms underlying this control are not understood. Taking both a theoretical and experimental approach, we examined several competing models that focus on whether there is IgE-regulated loss, IgE-regulated synthesis, or both regulated loss and synthesis of the Fc receptor for IgE (FcɛRI). We report that removing IgE from occupied FcɛRI resulted in an accelerated loss only in the unoccupied receptor, with no loss of occupied receptors and no loss of total receptors when all receptors were occupied. Together with previous studies, these results establish that there was IgE-regulated loss of receptors. An examination of synthetic rates of FcɛRIα using pulse-labeling with 35S-methionine indicated no difference in synthetic rates in the presence or absence of IgE. Similarly, the presence or absence of IgE had no influence on the levels of mRNA for either α, β, or γ subunits of FcɛRI. Using model simulations, we found that regulated-synthesis models could be distinguished from regulated-loss/constant-synthesis models on the basis of the relationship between starting FcɛRI densities and changes in density after culture for 1 week in the absence of IgE. Experimental data from this type of study fit a regulated-loss model that did not include regulation of synthesis. Taken together, these results suggest that IgE regulates cell surface expression of FcɛRI only by regulating the rate that receptor is lost from the cell surface.
Expression of CD94 and NKG2 molecules on human CD4+ T cells in response to CD3-mediated stimulation
Authors: Romero Pilar , Ortega Consuelo , Palma Agustín , Molina Ignacio J , Peña José , Santamaría Manuel
Published: September 2022

We investigated the ability of human peripheral CD4+ cellsto express CD94 and NKG2 molecules as a consequence ofCD3-mediated activation. Using highly purified peripheralCD4+ T cells, we found expression of both CD94 and NKG2A 15days after CD3-mediated stimulation of cells. We also determined byreverse transcriptase-PCR that all gene members of NKG2 family—namely,NKG2A, -C, -D, and -E—are sequentially expressed on CD4+cells. We found that this expression is tightly regulated by cytokines,and we identified transforming growth factor-β1 and interleukin-10 asthe main factors that, on CD3-dependent stimulation, positivelycontribute to the expression of CD94 and NKG2A on CD4+cells. We also investigated the functional role of NKG2A and found thatcoligation of CD3 and NKG2A by specific monoclonal antibodies resultsin significant inhibition of interferon γ and tumor necrosis factorα production by stimulated CD4+ cells. The presence andfunction of these receptors on CD4+ lymphocytes support amore general role for NKG2 molecules, whose functions were originallythought to be confined to cytotoxic cells, in the immune system.