Activation of thromboxane receptor modulates interleukin-1β-induced monocyte adhesion--a novel role of Nox1

Activation of thromboxane receptors (TPr) may promote atherosclerosis by enhancing oxidative stress and inflammation. This study examined the role of Nox1, an NADPH-oxidase subunit, in the enhancement of interleukin (IL)-1β-induced monocyte adhesion by TPr. In cultured rat aortic vascular smooth muscle cells (VSMCs), U46619, a stable thromboxane A(2) mimetic, together with interleukin-1β significantly enhanced Nox1 mRNA expression, as well as adhesion of THP-1 monocytes. Activation of TPr also enhanced IL-1β-induced vascular cell adhesion molecule (VCAM)-1 expression, but inhibited inducible nitric oxide synthase (iNOS) expression. Silencing Nox1 expression by siRNA prevented the U46619 enhancement of IL-1β-induced monocyte adhesion, but had no significant effect on VCAM-1 or iNOS expression. Furthermore, monocyte adhesion was inhibited by superoxide dismutase, enhanced by a specific iNOS inhibitor, l-N(6)-(1-iminoethyl)-lysine, but not influenced by catalase. U46619 inhibited IL-1β-induced cyclic GMP production, and the inhibition was partially prevented by superoxide dismutase. In conclusion, activation of TPr enhances IL-1β-induced Nox1 expression in VSMCs, which is responsible for the up-regulation of monocyte adhesion. The effect of Nox1 is independent of the changes in VCAM-1 and iNOS expression, but depends on the inactivation of nitric oxide via generation of superoxide anion.     

Transforming growth factor-β1 enhances the secretion of monocyte chemoattractant protein-1 by the IEC-18 intestinal epithelial cell line

Summary Intestinal epithelial cells (IEC) are known to produce monocyte chemoattractant protein-1 (MCP-1). However, MCP-1 production, as with many other cytokines, can be regulated by a network of cytokines present in the environment of the IEC. Both IEC and inflammatory cells have been shown to produce transforming growth factor-β (TGF-β), and the regulatory effect of this cytokine on MCP-1 secretion by IEC has not been determined. Using the IEC-18 cell line, we have found that TGF-β1 alone induced the secretion of high levels of MCP-1. Treatment with TGF-β1 also enhanced the levels of MCP-1 messenger ribonucleic acid. However, costimulation of the cells with TGF-β1 and interleukin-1β (IL-1β) resulted in significant, but less than additive, increases in MCP-1 secretion. Finally, the enhancing effect of TGF-β1 on MCP-1 secretion was not due to IL-6. These results suggest that TGF-β1 from IEC or inflammatory cells may significantly enhance the secretion of MCP-1 by IEC and play an important role in inflamed mucosal tissues.     

Tumor cytotoxicity of human monocyte membrane-bound interleukin-1α induced by synergistic actions of interferon-γ and synthetic acyltripeptide,FK-565

Summary Human blood monocytes were isolated by counter-flow centrifugal elutriation from healthy donors and these noncytotoxic monocytes were rendered tumoricidal to allogeneic melanoma (A375) cells by activation with a synthetic acyltripeptide (FK-565), as assessed by measuring release of [¹²⁵I]iododeoxyuridine in 72 h. When monocytes were treated with FK-565 for 16 h, and then fixed with paraformaldehyde, they showed cytotoxicity to A375 melanoma cells. The fixed-monocyte-mediated cytotoxicity to A375 cells was induced by the synergistic actions of FK-565 and recombinant interferon- (rIFN-), but not other cytokines [rIFN-A, rIFN-, tumor necrosis factor (TNF), interleukin (IL)-2, -3 and -6]. For synergistic activation of monocytes with induction of a membrane-associated antitumor monokine, the monocytes had to be incubated first with rIFN- and then with FK-565. FK-565 also acted synergistically with rIFN- to stimulate monocytes to produce membrane-associated IL-1 activity, which induced C3H/HeJ thymocyte blastogenesis in response to phytohemagglutinin P. The tumoricidal and thymocytestimulating activities of the fixed monocytes were almost completely inhibited by a specific anti-(IL-1) antiserum, but not by a specific anti-(IL-1) antiserum or monoclonal anti-TNF antibody. These results suggest that membrane-associated IL-1 of human blood monocytes can be induced by two activation signals (rIFN- then FK-565) at their suboptimal concentrations.Abbreviations IL interleukin - IFN interferon - TNF tumor necrosis factor     

Human blood monocyte activation byNocardia rubra cell wall skeleton for productions of interleukin 1 and tumor necrosis factor-α

Human blood monocytes were obtained from peripheral blood of healthy donors by counter-flow centrifugal elutriation. Functional integrity of monocytes for production of interleukin 1 (IL-1) and tumor necrosis factor (TNF-) in response toNocardia rubra cell wall skeleton (N-CWS) was examined by bioassay and enzyme immunoassay. Monocytes treated with N-CWS at more than 0.5 g/ml produced IL-1 and TNF- extracellularly. Extracellular TNF activity appeared within 4 h, and maximally, 16 h after N-CWS stimulation, whereas longer time was needed for IL-1 activity to appear, the peak production being at 24 h. The neutralizing experiment also showed that anti TNF- antibody did not affect IL-1 production by the monocytes treated with N-CWS, suggesting independen cy of IL-1 production of TNF-.These results suggest that the therapeutic antitumor effect of N-CWS is due, in part at least, to the augmented production of these monokines.     

No association of monocyte chemoattractant protein-1 −2518 A/G polymorphism with the risk of primary glomerulonephritis in the Polish population

Various studies have indicated that chemokines such as monocyte chemotactic protein-1 (MCP-1) play an important role in the pathogenesis of primary glomerulonephritis (GN) and other glomerular diseases. Moreover, patients with primary GN display aberrant galactosylation of the O-linked carbohydrate moieties of IgA. Therefore, we analysed the distribution of the functional MCP-1 −2518 A > G (rs 1024611) and 1 beta 1,3-galactosyltransferase (C1GalT1) 1365 A > G (rs1047763) polymorphic variants in patients with primary GN (n = 144) and controls (n = 437) in a sample of the Polish population. We did not find a significant difference in the prevalence of the MCP-1 −2518 A > G and C1GalT1 1365 A > G polymorphisms in patients with primary GN and healthy individuals. Odds Ratio (OR) for GN patients with the MCP-1 −2518 GG genotype was 0.869 (95% CI = 0.410–1.840, P = 0.7130), and OR of the −2518 GG and −2518AG genotypes was 1.004 (95% CI = 0.689–1.464, P = 0.9836). OR for C1GalT1 1365AA genotype was 0.484 (95% CI = 0.181–1.293, P = 0.1402) and OR of the 1365AA and 1365AG genotypes was 0.839 (95% CI = 0.573–1.228, P = 0.3651). We also did not observe a difference in the distribution of alleles between patients and controls. The MCP-1 −2518 G allelic OR was 0.976 (95% CI = 0.725–1.314, P = 0.8744). The OR for the C1GalT1 1365A allele was 0.816 (95% CI = 0.596–1.118, P = 0.205). Moreover, there was no significant association between the MCP-1 −2518 A > G and C1GalT1 1365 A > G genotypes with different morphological types of primary GN or clinical manifestations. Our observations indicate that the MCP-1 −2518 A > G and C1GalT1 1365 A > G polymorphisms might not be a risk factor in the incidence of primary GN in the Polish population.     

Peptide fragment 66–77 of monocyte chemoattractant protein 1 and its retro-enantio analogue inhibit the migration of cells in vitro and in vivo

The retro-enantio-analogue of peptide 66–77 of the chemokine MCP-1 and two hexapeptide fragments 66–71 and 72–77 of the C-terminal sequence of this protein were synthesized using the Fmoc strategy of solid phase peptide synthesis. The effect of the synthetic peptides upon the MCP-1-stimulated migration of THP-1 mononuclear cells was studied in vitro. The activity of the retro-enantio analogue was found to be comparable with that of the initial peptide 66–77: both peptides inhibit the migration of monocytes and granulocytes into inflammation zones of experimental animals.     

Sarpogrelate inhibits the expression of ICAM-1 and monocyte–endothelial adhesion induced by high glucose in human endothelial cells

Hyperglycemia is the major cause of diabetic angiopathy. Sarpogrelate hydrochloride is an antiplatelet drug, and expected to be useful in the treatment of chronic arterial occlusive diseases. The aim of our study was to evaluate the possible effects of sarpogrelate hydrochloride on adhesion molecule expression and its underlying mechanism in the prevention and treatment of cardiovascular disorders. Intercellular adhesion molecule-1 (ICAM-1) expression and superoxide dismutase (SOD) activity were determined after endothelial cells were exposed to high glucose in the absence and presence of sarpogrelate hydrochloride. Coincubation of endothelial cells with high glucose for 24 h resulted in a significant increase of monocyte–endothelial cell adhesion and the expression of ICAM-1 (P < 0.01). These effects were abolished by sarpogrelate hydrochloride and sarpogrelate hydrochloride significantly increased SOD activities (40 ± 8 vs. 47 ± 7, n = 8, P < 0.01). The low dose sarpogrelate group (0.1 μM) had significantly higher monocyte–endothelial cell adhesion and the expression of ICAM-1 than medium dose sarpogrelate group (1.0 μM) and high dose sarpogrelate group (10.0 μM) (P < 0.05 for comparison among three groups and P < 0.01 for difference between low and high dose sarpogrelate groups). These findings suggested that sarpogrelate hydrochloride was able to protect vascular endothelium from dysfunction induced by high glucose.     

Actin polymerization stabilizes α4β1 integrin anchors that mediate monocyte adhesion

Leukocytes arrested on inflamed endothelium via integrins are subjected to force imparted by flowing blood. How leukocytes respond to this force and resist detachment is poorly understood. Live-cell imaging with Lifeact-transfected U937 cells revealed that force triggers actin polymerization at upstream α4β1 integrin adhesion sites and the adjacent cortical cytoskeleton. Scanning electron microscopy revealed that this culminates in the formation of structures that anchor monocyte adhesion. Inhibition of actin polymerization resulted in cell deformation, displacement, and detachment. Transfection of dominant-negative constructs and inhibition of function or expression revealed key signaling steps required for upstream actin polymerization and adhesion stabilization. These included activation of Rap1, phosphoinositide 3-kinase γ isoform, and Rac but not Cdc42. Thus, rapid signaling and structural adaptations enable leukocytes to stabilize adhesion and resist detachment forces.     

Production of IFN-β during Listeria monocytogenes infection is restricted to monocyte/macrophage lineage

The family of type I interferons (IFN), which consists of several IFN-α and one IFN-β, are produced not only after stimulation by viruses, but also after infection with non-viral pathogens. In the course of bacterial infections, these cytokines could be beneficial or detrimental. IFN-β is the primary member of type I IFN that initiates a cascade of IFN-α production. Here we addressed the question which cells are responsible for IFN-β expression after infection with the intracellular pathogen Listeria monocytogenes by using a genetic approach. By means of newly established reporter mice, maximum of IFN-β expression was observed at 24 hours post infection in spleen and, surprisingly, 48 hours post infection in colonized cervical and inguinal lymph nodes. Colonization of lymph nodes was independent of the type I IFN signaling, as well as bacterial dose and strain. Using cell specific reporter function and conditional deletions we could define cells expressing LysM as the major IFN-β producers, with cells formerly defined as Tip-DCs being the highest. Neutrophilic granulocytes, dendritic cells and plasmacytoid dendritic cells did not significantly contribute to type I IFN production.     

The effects of γ-interferon on human peripheral blood monocyte/macrophage-mediated bone particle degradation

γ-Interferon (IFN-γ) has recently been demonstrated to inhibit the ability of mononuclcar phagocytes to degrade bone particles. We have further addressed the specificity, potency and mechanism of this activity using human recombinant IFN-γ. Adherent peripheral blood mononuclear leukocytes from normal human volunteers were cultured with washed, sieved (⩽75 μm) ⁴⁵Ca-labelled rat bone particles for 3 days, after which bone particle degradation (7.1 ± 1.6%, n = 11) was calculated from the fraction of⁴⁵Ca released into the medium. As little as 5 U/ml IFN-γ significantly suppressed bone particle degradation and 50 U/ml was associated with consistent marked suppression (74.0 ± 3.5% inhibition, P < 0.001, n = 11). IFN-γ was not suppressive if added to cells 24 h or more after exposure to bone particles. Addition of indomethacin (10 μM) did not reverse the effect of IFN-γ, suggesting that it was not prostaglandin-mediated. In addition, 1,25(OH)₂D₃ (10 nM) did not remove the inhibitor, effect of IFN-γ.Contact of mononuclear phagocytes with bone particles and secretion of soluble factors from these cells have both been demonstrated to play a role in their ability to degrade bone particles. IFN-γ (50 U/ml) inhibited monocyte/macrophage interaction with another unopsonized surface, i.e., one μm fluorescent latex particles, decreasing the number of internalized particles from 12.6 ± 2.9 per cell to 5.9 ± 1.4 per cell (P < 0.01, n = 15), as measured using flow cytometry. However, binding of bone particles by the cells was not diminished by IFN-γ. Exogenous α-imerferon and human recombinant IL-1β, TNF-α, and lymphotoxin did not alter bone particle degradation. In addition, endogenous IL-1β release from human monocyte/macrophages exposed to bone particles was negligible and unaffected by IFN-γ.We conclude that IFN-γ is a potent and specific inhibitor of monocyte/macrophage-mediated bone particle degradation, and that this activity does not appear to be due to effects on the ability of monocytes to bind bone particles or to release IL-1 in response to the particles     

Expression of cell kinetics and death during monocyte–macrophage differentiation: effects of Actinomycin D and Vinblastine treatments

The different effects of two cytostatic drugs, Actinomycin D and Vinblastine, during macrophage-like differentiation induced in THP-1 monocytic cell line by phorbol ester phorbol 12-myristate 13-acetate (PMA) (6, 30, and 60 nM), were studied by morpho-cytochemical approaches. In PMA-unstimulated monocytic cells, the cytostatic effects of Actinomycin D (an antimetabolic drug) were characterized by a drastic reduction of the G2/M cells accompanied by dramatic death of the G1 cells; on the contrary, Vinblastine (a microtubule-depolymerizating drug) induced an accumulation of the G2/M cells with the appearance of aneugenic micronuclei and scarce cell death mainly from the G1 cells. After 60 nM PMA stimulation, the culture was mostly composed by macrophagic cells characterized by low proliferation and the appearance of mono-/binucleated polyploid cells; in this condition, the cytotoxicity of the two drugs, more effective for Vinblastine, induced cell death in the different ploidy classes (2c, 4c, 8c). Cell death appeared to be of apoptotic nature, but with some morpho-phenotypic differences due to the action mechanism of the drugs and dependent on cell culture growth and differentiation. As a consequence of the different block-action of the two drugs on the cell cycle phases and in relation to the different subcellular targets, the effects changed during the transition from not-adhering/proliferating monocytes to adhering/low-proliferating differentiated macrophages.     

NHE-1 and β1 integrin-dependent monocyte adhesion and migration after glucose,insulin or PPARγ stimulation

In the present study the effect of high glucose concentrations, insulin, PPARγ activators (rosiglitazone) and NHE-1 inhibitors (cariporide) in atherosclerosis-related functions of human monocytes was investigated. Monocyte adhesion to laminin-1, collagen type IV and endothelial cells, as well as monocyte migration through the same substrates were studied. Incubation of the monocyte suspension with high glucose concentrations, insulin and rosiglitazone induced all the studied atherosclerosis-related functions of the monocytes. In all these functions the addition of cariporide counteracted the activity of glucose, insulin and rosiglitazone. The use of antigen for β1 integrin also counteracted the activity of the above in monocyte adhesion in all three substrates. The data of the present study suggests that PPARγ activation in monocytes induces atherosclerosis, and that NHE-1 and β1 integrin play an important role in the beginning of atherosclerosis.Key words: monocytes, atherosclerosis-related functions, cell adhesion, cell migration, integrins, rosiglitazone, glucose, insulin, laminin-1, collagen type IV, endothelial cells     

Profiling signalling pathways of the receptor activator of NF-κB ligand-induced osteoclast formation in mouse monocyte cells,RAW264.7

Summary. Cell-based signal chemical genomics can profile the signalling pathway for certain cellular events by using a target-known chemical library. To ascertain its usefulness, the receptor activator of NF-κB ligand (RANKL)-induced osteoclastogenesis in mouse monocyte/macrophage cells RAW264.7 was used as an in vitro experimental model. Of 180 target-known inhibitors/activators formatted in a 384-well plate, 8 chemicals were shown to inhibit the osteoclast formation, but 4 chemicals enhanced this process. A variety of references support, or possibly lead one to expect the effects of these 12 chemicals on the cellular process of osteoclastogenesis in RAW264.7 cells, but several signalling pathways were newly found in this study; for example, CA-074 Me inhibiting cathepsin B and nitrendipine blocking the calcium channel could have the potential to inhibit the osteoclast formation as well as bone resorption. This is a simple but very fast and powerful method of profiling the signalling pathway of certain cellular events. Signal chemical genomics could provide invaluable information for the exploration of new target signalling processes and further target-based drug discovery strategies. Authors’ address: Seong Hwan Kim, PhD, Laboratory of Chemical Genomics, Bio-Organic Science Division, Korea Research Institute of Chemical Technology, P.O. Box 107, Yuseong-gu, Daejeon 305-600, Korea     

Functional monocyte chemoattractant protein-1 promoter −2518 polymorphism and systemic lupus erythematosus: a meta-analysis

The monocyte chemoattractant protein-1 (MCP-1) promoter −2518 A/G polymorphism has been reported inconsistently to be associated with systemic lupus erythematosus (SLE) and lupus nephritis (LN). The aim of this study was to explore whether the MCP-1 polymorphism confers susceptibility to SLE or LN. We surveyed studies on the MCP-1 polymorphism and SLE or LN identified by MEDLINE or manual searches. Meta-analysis was conducted on the AA genotype (recessive effect), AA, and AG genotypes (dominant effect), AA versus GG (genotype contrast), and on the A allele of MCP-1 in SLE and LN in each ethnic population studied and on all subjects. Ten studies, which included 1,739 SLE patients and 1,680 controls, were included in our meta-analysis. These consisted of two European, six Asian, one Latin American, and one mixed study. We did not find any association between the MCP-1 −2518 A/G polymorphism and SLE in all subjects or in ethnic groups. Meta-analysis also failed to reveal an association between the MCP-1 −2518 A/G polymorphisms and LN. This meta-analysis on 3419 subjects indicates that no association exists between the MCP-1 −2518 A/G polymorphism and SLE or LN.     

SVEP1 influences monocyte to macrophage differentiation via integrin α4β1/α9β1 and Rho/Rac signalling

BackgroundThe large extracellular matrix protein SVEP1 mediates cell adhesion via integrin α9β1. Recent studies have identified an association between a missense variant in SVEP1 and increased risk of coronary artery disease (CAD) in humans and in mice Svep1 deficiency alters the development of atherosclerotic plaques. However how SVEP1 functionally contributes to CAD pathogenesis is not fully understood. Monocyte recruitment and differentiation to macrophages is a key step in the development of atherosclerosis. Here, we investigated the requirement for SVEP1 in this process.MethodsSVEP1 expression was measured during monocyte–macrophage differentiation in primary monocytes and THP-1 human monocytic cells. SVEP1 knockout THP-1 cell lines and the dual integrin α4β1/α9β1 inhibitor, BOP, were utilised to investigate the effect of these proteins in THP-1 cell adhesion, migration and cell spreading assays. Subsequent activation of downstream integrin signalling intermediaries was quantified by western blotting.ResultsSVEP1 gene expression increases in monocyte to macrophage differentiation in human primary monocytes and THP-1 cells. Using two SVEP1 knockout THP-1 cells we observed reduction in monocyte adhesion, migration, and cell spreading compared to control cells. Similar results were found with integrin α4β1/α9β1 inhibition. We demonstrate reduced activity of Rho and Rac1 in SVEP1 knockout THP-1 cells.ConclusionsSVEP1 regulates monocyte recruitment and differentiation phenotypes through an integrin α4β1/α9β1 dependent mechanism.General significanceThese results describe a novel role for SVEP1 in monocyte behaviour relevant to CAD pathophysiology.     

α-Tocopherol supplementation does not affect monocyte endothelial adhesion or C-reactive protein levels but reduces soluble vascular adhesion molecule-1 in the plasma of healthy subjects

Abstract

Vascular monocyte retention in the subintima is pivotal to the development of cardiovascular disease and is facilitated by up-regulation of adhesion molecules on monocytes/endothelial cells during oxidative stress. Epidemiological studies have shown that cardiovascular disease risk is inversely proportional to plasma levels of the dietary micronutrients, vitamin C and vitamin E (α-tocopherol). We have tested the hypothesis that α-tocopherol supplementation may alter endothelial/monocyte function and interaction in subjects with normal ascorbate levels (> 50 μM), as ascorbate has been shown to regenerate tocopherol from its oxidised tocopheroxyl radical form in vitro. Healthy male subjects received α-tocopherol supplements (400 IU RRR-α-tocopherol/day for 6 weeks) in a placebo-controlled, double-blind intervention study. There were no significant differences in monocyte CD11b expression, monocyte adhesion to endothelial cells, plasma C-reactive protein or sICAM-1 concentrations post-supplementation. There was no evidence for nuclear translocation of NF-κB in isolated resting monocytes, nor any effect of α-tocopherol supplementation. However, post-supplementation, sVCAM-1 levels were decreased in all subjects and sE-selectin levels were increased in the vitamin C-replete group only; a weak positive correlation was observed between sE-selectin and α-tocopherol concentration. In conclusion, α-tocopherol supplementation had little effect on cardiovascular disease risk factors in healthy subjects and the effects of tocopherol were not consistently affected by plasma vitamin C concentration.     

Endothelial surface N-glycans mediate monocyte adhesion and are targets for anti-inflammatory effects of peroxisome proliferator-activated receptor γ ligands

Endothelial-monocyte interactions are regulated by adhesion molecules and key in the development of vascular inflammatory disease. Peroxisome proliferator-activated receptor (PPAR) γ activation in endothelial cells is recognized to mediate anti-inflammatory effects that inhibit monocyte rolling and adhesion. Herein, evidence is provided for a novel mechanism for the anti-inflammatory effects of PPARγ ligand action that involves inhibition of proinflammatory cytokine-dependent up-regulation of endothelial N-glycans. TNFα treatment of human umbilical vein endothelial cells increased surface expression of high mannose/hybrid N-glycans. A role for these sugars in mediating THP-1 or primary human monocyte rolling and adhesion was indicated by competition studies in which addition of α-methylmannose, but not α-methylglucose, inhibited monocyte rolling and adhesion during flow, but not under static conditions. This result supports the notion that adhesion molecules provide scaffolds for sugar epitopes to mediate adhesion with cognate receptors. A panel of structurally distinct PPARγ agonists all decreased TNFα-dependent expression of endothelial high mannose/hybrid N-glycans. Using rosiglitazone as a model PPARγ agonist, which decreased TNFα-induced high mannose N-glycan expression, we demonstrate a role for these carbohydrate residues in THP-1 rolling and adhesion that is independent of endothelial surface adhesion molecule expression (ICAM-1 and E-selectin). Data from N-glycan processing gene arrays identified α-mannosidases (MAN1A2 and MAN1C1) as targets for down-regulation by TNFα, which was reversed by rosiglitazone, a result consistent with altered high mannose/hybrid N-glycan epitopes. Taken together we propose a novel anti-inflammatory mechanism of endothelial PPARγ activation that involves targeting protein post-translational modification of adhesion molecules, specifically N-glycosylation.     

α-Helix peptides designed from EBV-gH protein display higher antigenicity and induction of monocyte apoptosis than the native peptide

We tested the hypothesis that stabilizing α-helix of Epstein–Barr virus gH-derived peptide 11438 used for binding human cells will increase its biological activity. Non-stable α-helix of peptide 11438 was unfolded in an entropy-driven process, despite the opposing effect of the enthalpy factor. Adding and/or changing amino acids in peptide 11438 allowed the designing of peptides 33207, 33208 and 33210; peptides 33208 and 33210 displayed higher helical content due to a decreased unfolding entropy change as was determined by AGADIR, molecular dynamics and circular dichroism analysis. Peptides 33207, 33208 and 33210 inhibited EBV invasion of peripheral blood mononuclear cells and displayed epitopes more similar to native protein than peptide 11438; these peptides could be useful for detecting antibodies induced by native gH protein since they displayed high reactivity with anti-EBV antibodies. Anti-peptide 33207 antibodies showed higher reactivity with EBV than anti-peptide 11438 antibodies being useful for inducing antibodies against EBV. Anti-peptide 33210 antibodies inhibit EBV invasion of epithelial cells better than anti-peptide 11438 antibodies. Peptide 33210 bound to normal T lymphocytes and Raji cells stronger than peptide 11438 and also induced apoptosis of monocytes and Raji cells but not of normal T cells in a similar way to EBV-gH. Peptide 33210 inhibited the monocytes’ development toward dendritic cells better than EBV and peptide 11438. In conclusion, stabilizing the α-helix in peptides 33208 and 33210 designed from peptide 11438 increased the antigenicity and the ability of the antibodies induced by peptides of inhibiting EBV invasion of host cells.