Spontaneous Adherence Research Articles

The Importance of Mapping Determinants, Attitudes and Beliefs of Vaccine Hesitancy in the Great Challenge of Compulsory Childhood Vaccination Comment on "Convergence on Coercion: Functional and Political Pressures as Drivers of Global Childhood Vaccine Mandates".

Vaccine hesitancy (VH) has risen significantly during the COVID-19 pandemic, becoming a major global health concern. VH is characterized by the delay or refusal of vaccination despite its availability. Various frameworks have been developed to understand the complex factors influencing VH, with attitudes, beliefs, and external influences being the most significant. The surge in VH has reignited the debate on the best approach to address it: persuasive/ educational or coercive. Attwell and Hannah studied the political and social reasons behind the adoption of mandatory vaccination in four jurisdictions (Italy, France, Australia, and California) due to declining vaccine coverage below the safety threshold. However, these methods may foster parental disbeliefs and opposition to vaccination campaigns. To combat VH, it is crucial to systematically assess its determinants within specific contexts and population groups. Increasing awareness about vaccination benefits, engaging with social media, and employing tailored strategies can foster spontaneous adherence to vaccination programs, eliminating the need for coercive measures.

The need of rebubbling in case of small graft detachments after Descemet Membrane Endothelial Keratoplasty (DMEK).

To investigate the need of rebubbling for small graft detachments after Descemet Membrane Endothelial Keratoplasty (DMEK). In this retrospective study we evaluated 111 eyes from 111 patients that showed graft detachment after DMEK surgery and have achieved graft adherence by injection of air or 20% sulfur hexafluoride (SF6) to the anterior chamber (rebubbling group; n = 57) or by spontaneous adherence without intervention (control group; n = 54) at final examination. Subgroups in terms of the maximum height and in terms of the detachment area in relation to graft area were formed. Outcome measures were the increase in best-corrected visual acuity (BCVA) and the decrease in central corneal thickness (CCT) from the measurement before DMEK to six months after surgery and postoperative endothelial cell density. BCVA increased in the rebubbling group and the control group, the difference being 0.22 logMAR, p = 0.048. For eyes with a maximum height less than 500 µm, the increase of BCVA was 0.39 ± 0,36 logMAR in the control group and 0.62 ± 0,53 logMAR in the rebubbling group, p = 0.045. There was no difference of statistical significance of BCVA between both groups regarding the detachment area of less than 20% in relation to graft area. The mean decrease in CCT and postoperative endothelial cell density showed no significant difference between the rebubbling group and the control group. Compared to spontaneous graft adherence, a rebubbling shows no beneficial effect on the clinical outcome for small detached DMEK grafts. Rebubbling does not decrease postoperative endothelial cell density.

Mandatory COVID-19 vaccination for healthcare professionals: ethical perspectives

Following the availability of new vaccines against COVID-19, in 2021, some countries introduced mandatory vaccination for healthcare professionals caring for patients and frail people. This work highlights the principles of public ethics which, reinforced by some fundamental ethical precepts, make mandatory vaccination legally acceptable. However, there are also problems, linked to the presence of the phenomenon of vaccine hesitancy among health professionals, in low percentages but with high incidence. In the context of the care relationship, the ethical tension between the autonomy claimed by the healthcare provider and the patient’s right to safety emerges. Vaccination does not provide absolute protection, but it makes an important contribution to the safety of the care environment. We believe that mandatory vaccination of healthcare professionals is compatible with the ethical precept of protecting the health of the community and the patients entrusted to their care. Individual freedom cannot increase the risk of patients. The ethical perspective suggests that public decision-makers should encourage spontaneous adherence to vaccines as much as possible and adopt the strategy of progressive intervention, inspired by the principle of proportionality.

Prophage Excision in Streptococcus pneumoniae Serotype 19A ST320 Promote Colonization: Insight Into Its Evolution From the Ancestral Clone Taiwan 19F-14 (ST236).

Streptococcus pneumoniae 19A ST320, a multidrug-resistant strain with high disease severity that notoriously spread before the use of expanded pneumococcal conjugate vaccines, was derived from a capsular switching event between an international strain Taiwan 19F-14 (ST236) and a serotype 19A strain. However, the molecular mechanisms underlying the adaptive evolution of 19F ST236 to 19A ST320 are unknown. In this study, we compared 19A ST320 to its ancestral clone, 19F ST236, in terms of adherence to respiratory epithelial cells, whole transcriptome, and ability to colonize a young mouse model. Serotype 19A ST320 showed five-fold higher adherence to A549 cells than serotype 19F ST236. High-throughput mRNA sequencing identified a prophage region located between dnaN and ychF in both strains; however, the genes in this region were expressed at significantly higher levels in 19A ST320 than in 19F ST236. Analysis by polymerase chain reaction (PCR) showed that the prophage is able to spontaneously excise from the chromosome and form a circular episome in 19A ST320, but not in 19F ST236. Deletion of the integrase in the prophage of 19A ST320 decreased spontaneous excision and cell adherence, which were restored by complementation. Competition experiments in mice showed that the integrase mutant was six-fold less competitive than the 19A ST320 parent (competitive index [CI]: 0.16; p = 0.02). The 19A ST320 prophage-deleted strain did not change cell adherence capacity, whereas prophage integration strains (integrase mutant and 19F) had decreased expression of the down-stream ychF gene compared to that of 19A ST320. Further deletion of ychF significantly reduced cell adherence. In conclusions, these findings suggest that spontaneous prophage induction confers a competitive advantage to virulent pneumococci.

Remarkable performance of magnetized chitosan-decorated lignocellulose fiber towards biosorptive removal of acidic azo colorant from aqueous environment

Numerous low-cost adsorbents have been used for removal of harmful azo colorants from aqueous environment, but they frequently suffer from either low/limited adsorption capacity or slow adsorption kinetics; moreover, almost all of them become problematic on the regard of recycling and reuse. This research explores the possibility of using a novel low-cost biocomposite, i.e., magnetized chitosan-coated lignocellulose fiber, for biosorptive removal of acidic azo colorant from aqueous solution. This chitosan-decorated lignocellulose fiber (CS/LCF) was prepared for the first time via a facile “surface deposition–crosslinking” method, exhibiting a well-defined coating structure. Interestingly, the CS/LCF could be easily magnetized by simply blending it with magnetic nanoparticle (MNP) in an aqueous solution because of the spontaneous adherence of MNP to CS/LCF surface. More importantly, the magnetized CS/LCF was found to be exceptionally effective and efficient in biosorptive removal of acidic azo compound (i.e., acid red 18), e.g., ultrahigh adsorption capacity (up to 1184mgg−1), rapid adsorption rate, excellent reusability (with removal efficiency up to 99.48% in tenth cycle), and convenience in manipulation (magnetic separation). The inherent advantages of the magnetically retrievable CS/LCF may pave a new, inexpensive, efficient, and sustainable way towards removal of acidic azo colorants from Earth's water environments.

Disk Lubricant Additives, A20H and C2: Characteristics and Chemistry in the Disk Environment

Disk lubricant additives A20H and C2 are Fomblin Z type perfluoropolyether with the hydroxyl end-group, –O–CF2–CH2–OH, at one end, and the cyclo-triphosphazene end-group, R5(PN)3–O–, at the other end. Here, R is an m-trifluoromethyl-phenoxy group for A20H and a trifluoroethoxy group for C2. These additives were examined for miscibility with benzene, spin-off rate, water contact angle, and the diffusion rate over the carbon overcoat. It is revealed that A20H adheres to the carbon overcoat spontaneously. The attractive interaction arises from the charge–transfer type interaction between the aromatic rings of the phosphazene end and the graphitic regime of the carbon overcoat. No spontaneous adherence occurs between the lubricant C2 and the carbon overcoat. A TOF-SIMS study of disks coated with A20H and C2, respectively, with and without subsequent curing by short-UV (185 nm) was performed. It is revealed: (1) if presented with a low energy electron, the phenoxy groups of A20H readily undergo the dissociative electron capture, while the trifluoroethoxy group does not, and (2) photoelectrons generated by short-UV have little kinetic energy and the electron capture occurs only if an electrophilic molecular sector is in intimate contact with the carbon. Thus, in the case of disks coated with A20H, UV-curing results in detachment of a phenoxy group in contact with the carbon, generation of a radical center at the phosphorus atom and subsequent formation of a bona fide chemical bond between the phosphor and the carbon overcoat. No reaction of consequence occurs when disks coated with C2 are irradiated with short-UV.

Monitoring spontaneous adherence to therapeutic guidelines in 500 cancer patients

6055 Background: Our institution adheres to recognized guidelines for cancer treatment (GCT) as those from NCI (USA) or NICE (UK). These are essential tools to our understanding, for monitoring quality of medical care. In a previous study, over 90% of physicians complied with these guidelines when they were included in a monitored program, however an evaluation of spontaneous (non monitored) adherence to GCT by practicing oncologists in our country is lacking and it was the purpose of the study. Methods: We retrieved from our database 500 consecutive requests for cancer treatment received from 1997 to 2004 from outside non monitored institutions. Results: The treatment received by 389 patients (78%) was according to GCT, whereas 111 (22.6%) were treated without any compliance of existing GCT’s. Major deviations from GCT were detected in this cohort, such as investigational treatments in 43 (8.6%), inadequate treatment for the actual stage of the disease 43 (8.6%), inadequate dosage: 13 (2.6%), lack of correlation between diagnosis and treatment prescribed 5 (1%) and delayed treatment 7 (1.4%). Compared to our historical series of monitored prescriptions, the likelihood of receiving an inadequate therapy significantly increased when practicing oncologists were not monitored (p=0.0001). Conclusions: When treatment was not monitored, one every five patients received an inadequate therapy either because of inaccurate treatment for stage, incorrect dosing or by utilizing investigational treatments instead of a proven one. No significant financial relationships to disclose.

Modulation of Human Polymorphonuclear Leukocyte Adherence by Cyanopeptide Toxins

The oligopeptides microcystins and nodularins are the most common and abundant cyanotoxins present in diverse water systems. They cause different illnesses in animal and humans, sometimes leading to death, and are responsible for severe environmental problems. Here we demonstrate that both microcystin-LR and N. spumigena nodularin (Nod) significantly enhance the early spontaneous adherence of peripheral polymorphonuclear leukocytes (PMNs) over the concentration range 10−11–10−9 M. However, neither of them affect significantly the late spontaneous adherence or the early or late PMN-stimulated adherence (when cells are treated with formyl-methionyl-leucyl-phenylalanine). Since PMN adherence is a key step in the immune response, our data clearly indicate for the first time the immunomodulatory capacity of cyanopeptide toxins. The low concentrations at which the adherence modulation occurs are similar to the physiological concentrations for natural mammalian peptide hormones. Such concentrations are well below those recommended by other authors and World Health Organization in terms of risk assessment as safe for drinking water (8×10−10 to 10−9 M).

Reflexivity and its Consequences

The work of Pierre Bourdieu owes much of its distinctive qualities to its reflexive character, to the incisive and recurrent analysis of what it means to practise social science, to be an academic, or to speak out as an intellectual. The sociology of the intellectual world for Bourdieu is not so much a particular research specialty as an indispensable precondition for social scientific research. Reflexivity in this sense is a working method, recognizable in all of his various undertakings, whether they concern his research and teaching, the publishing of Liber and Actes de la recherche en sciences sociales, or his current activities in finding ways to redefine and revive the critical role of intellectuals.1 If, in contrast to this reflexive stance, there is anything lacking in Bourdieu’s writings, it is indeed the plain and spontaneous adherence to the established intellectual models. Bourdieu never quite identified himself with what was readily available, neither with the professorial fate of the academic specialist, nor with the Sartrean figure of the ‘total intellectual’. For a young French philosopher, originating from a province at about maximum distance from the capital, who had made it to the Ecole normale superieure, it was rather unusual, to say the least, to start ethnographic and sociological fieldwork in Algeria. Bourdieu’s subsequent work, marked by an unfailing refusal of the predominant dichotomies (theory/ research, objectivism/subjectivism, holism/individualism), testifies to the same unease with the primary divisions of the academic universe. His inability and unwillingness to be satisfied with the existing options is aptly illustrated by the dictum he quotes from Karl Krauss, the Viennese critic and writer: ‘Were I forced to choose between two evils, I would choose neither one’ (Bourdieu, 1997: 129). This inclination, visible in his way of constructing sentences and developing arguments, is at the root of acclaimed innovations in various research fields, and has, more generally, led him to conceive of social science as a reflexive endeavour. Bourdieu’s use of neither-nor reasoning is no rhetorical device, commonly employed to nestle oneself comfortably in the middle of two (often fictitious) extremes, but a way of gaining distance from the dominant views, allowing a reflection upon what is at stake for whom, and why some things are conceivable from one point of view, whereas others are not. This reflexive urge, which simultaneously questions a specific object and those who question the object in question, is present from his earliest work onwards. European Journal of Social Theory 2(3): 298–306

During human thymic development, beta 1 integrins regulate adhesion, motility, and the outcome of RHAMM/hyaluronan engagement.

During human thymic differentiation, interactions between fibronectin (Fn)/beta1 integrins and hyaluronan (HA)/RHAMM control motility and Fn/beta1 integrins mediate spontaneous Fn-dependent adhesion. Multinegative (MN, CD3-4-8-) thymocytes exhibit strong spontaneous adherence to Fn (75%) that was efficiently inhibited by anti-alpha5beta1 and only weakly inhibited by anti-alpha4beta1. The relatively weak adherence of unfractionated thymocytes to Fn required both alpha4beta1 and alpha5beta1. Video time-lapse microscopy indicates that a subset of thymocytes also undergo spontaneous Fn-dependent motility mediated by alpha5beta1, alpha4beta1, and the HA-receptor RHAMM, but not by CD44. The loss of motility after hyaluronidase treatment of thymocytes indicated that motility is strongly dependent on HA. Of motile cells, 55% were DP, 19% were DN, and 24% were CD4+SP, but only 1% were CD8+SP. Overall, for MN thymocytes, beta1 integrin mediated Fn-adhesion, but after expression of CD4/CD8, beta1 integrins mediated Fn-dependent motility. Treatment with the activating anti-beta1 mAb QE.2E5 inhibited thymic motility and converted otherwise nonadherent thymocytes to an adherent state. High-avidity interactions via integrins appear to supercede the motogenicity of RHAMM and HA, suggesting that integrin avidity may regulate RHAMM. During thymic development, changes in adhesion or motility appear to be mediated by integrin avidity modulation.

Modified natural porcine surfactant inhibits superoxide anions and proinflammatory mediators released by resting and stimulated human monocytes.

Pulmonary surfactant has a potential role in modulating inflammation in normal and injured lungs. In lung injury, monocytes become activated and participate in lung inflammation. We therefore, investigated the proinflammatory functions of stimulated human blood monocytes after an overnight preincubation period with modified natural porcine surfactant (Curosurf) (500-1000 micrograms/mL). Monocytes were stimulated either with phorbol myristate acetate (PMA), bacterial extract OM-85, lipopolysaccharide (LPS), or Ca2+ ionophore A23187. The present study shows that Curosurf significantly inhibits: 1) the production of superoxide anions stimulated with OM-85 (1 mg/mL, 30 min), but not with PMA (100 ng/mL, 30 min); 2) the release of cyclooxygenase metabolites prostaglandin E2 and thromboxane B2 stimulated with OM-85 (1 mg/mL, overnight); 3) the release of lipoxygenase metabolite leukotriene C4 stimulated with A23187 (10 microM, 10 min); 4) the release of the cytokine TNF-alpha stimulated overnight with either OM-85 (1 mg/mL) or LPS (10 micrograms/mL)) in a dose-dependent fashion. In addition, Curosurf decreases the spontaneous adherence of monocytes to plastic culture wells in a dose-dependent fashion. Experiments performed with staurosporine, an inhibitor of protein kinase C (PKC) indicate that, in contrast with PMA, the production of superoxide anions stimulated by OM-85 is not related to PKC activation. Consequently, we propose that the mechanism involved in the suppressive effects of Curosurf is PKC-independent. In summary, the present study provides experimental evidence that favors the anti-inflammatory role of modified natural porcine surfactant (Curosurf) in human monocytes in vitro.

Free peripheral sulfhydryl groups, CD11/CD18 integrins, and calcium are required in the cadmium and nickel enhancement of human-polymorphonuclear leukocyte adherence

Cadmium and nickel stimulate the early spontaneous adherence of peripheral human polymorphonuclear leukocytes (PMNs). Formyl-methionylleucylphenylalanine (fMLP) at 0.25 nM inhibited the PMN adherence but was stimulated at 10 or 100 nM. Cadmium or nickel, nullified the FMLP inhibitory effect, and enhanced the adherence. No clear additive effect was noticed for either metal with fMLP. Blockade of CD11/CD18 receptors abolished the adherence modulatory effect of both fMLP and metals. p-Chloromercuriphenyl sulfonate (PCMPS), at a concentration that blocks peripheral SH groups, did not affect spontaneous adherence, but completely prevented the adherence enhancement caused by cadmium or nickel. Removal of extracellular calcium diminished both the spontaneous and the metal-stimulated adherence. Ryanodine, at a concentration that persistently inactivates ryanodine-sensitive intracellular channels, inhibited spontaneous PMN adherence, but had no effect on the cadmium or nickel induced adherence enhancement. Therefore, the results indicate that cadmium and nickel adherence stimulation depends on constitutive peripheral SH groups, CD11/CD18 integrins and extracellular calcium, but not on intracellular stored-calcium release through ryanodine-sensitive channels (RyRS). In contrast, spontaneous adherence greatly depends on the release of stored calcium through RyRs, and only slightly on extracellular calcium.

Eosinophil adhesion to vascular cell adhesion molecule-1 activates superoxide anion generation.

Adhesion to the adhesion protein, VCAM-1, on vascular endothelium is proposed to be an important factor in the selective accumulation of eosinophils at sites of allergic inflammation. To determine whether eosinophil adhesion to VCAM-1 is also associated with an alteration of eosinophil function, human peripheral blood eosinophils were isolated from allergic donors and incubated in VCAM-1-coated wells. Spontaneous adherence of isolated eosinophils to VCAM-1-coated wells was greater than cells incubated in FCS-treated control wells (38.0 +/- 1.6% vs 17.1 +/- 1.9%, n = 16, p < 0.0001). In addition, eosinophils incubated in VCAM-1-coated wells spontaneously generated modest but significant amounts of superoxide anion (O2-; 2.0 +/- 1.3 vs 00.5 +/- 0.5 nmol/5 x 10(5) cells, n = 9, p = 0.029). Moreover, when 100 nM FMLP was added to eosinophils in the presence of VCAM-1, significantly greater O2- generation occurred (7.2 +/- 0.9 vs 5.4 +/- 1.0 (FCS control) nmol/5 x 10(5) cells, n = 9, p = 0.009). Adhesion, as well as the spontaneous and enhanced O2- generation to FMLP activation, was blocked by the monoclonal anti-alpha 4 integrin Ab, HP 1/2, implying involvement of an alpha 4 integrin-VCAM-1 interaction. In contrast, the anti-CD18 mAb, L130, inhibited the spontaneous and enhanced O2- generation to FMLP without affecting adhesion, suggesting an involvement of CD18 molecule(s) only in VCAM-1-enhanced respiratory burst. Finally, 1 microM genistein, a tyrosine kinase inhibitor suppressed the VCAM-1-enhancing effect on eosinophil O2- generation and VCAM-1-induced tyrosine phosphorylation, suggesting a role for tyrosine phosphorylation in this eosinophil functional up-regulation. Our observations suggest that eosinophil adhesion to VCAM-1 may be an important step in determining the eventual functional activity of these cells as they migrate from the circulation to the airways and contribute to the allergic inflammatory process.

Modulation of the adherence of human polymorphonuclear leukocytes by cadmium and nickel: Sexual differences

The effect of cadmium (xenobiotic element) and nickel (ultra-trace bioelement) on the adherence to plastic of peripheral polymorphonuclear leukocytes (PMNs) from male (M-PMNs) and female (F-PMNs) donors was analyzed. Exposure of PMNs to either metal stimulated adherence, mainly the early adherence (8 min). A sex influence on the adherence was observed. Up to 45 min of incubation, M-PMNs adhered more than F-PMNs. This sexual dimorphism also took place in the case of metal stimulation. Cadmium and nickel enhanced early spontaneous adherence of cells from either sex, but only the late adherence (25 min) of F-PMNs. The adherence stimulation was generally greater in F-PMNs, but M-PMNs achieved higher adherence levels. Nickel was more effective than cadmium in enhancing the adherence, especially the early adherence of F-PMNs.

Heterodimers of the calcium-binding proteins MRP8 and MRP14 are expressed on the surface of human monocytes upon adherence to fibronectin and collagen. Relation to TNF-alpha, IL-6, and superoxide production.

The 27E10 antigen is a heterodimer of MRP8 and MRP14, two Ca(2+)-binding proteins related to the S-100 protein family. Previous studies have shown that 27E10 epitope-bearing monocyte subsets are prevalent in early acute but absent in chronic inflammatory conditions. These observations further provide an impetus for identifying the cellular mechanisms responsible for the appearance of different monocyte subpopulations during inflammation. Therefore this in vitro study was carried out to investigate the influence of adhesion in inducing 27E10-positive subsets. In adhesion assays the role of 27E10 antigen in spontaneous adherence was obvious, as a monoclonal antibody directed against the 27E10 antigen significantly inhibited the adherence of monocytes to collagen and fibronectin. In contrast, these extracellular matrix (ECM) proteins induce the cell surface expression and association of 27E10 antigen with cytoskeleton (CSK), detected by flow cytometry and confocal laser scan microscopy, respectively. Similar results were obtained on cross-linking with specific antibodies, thus showing involvement of the integrin molecules VLA-2 and VLA-4. In addition, the association with CSK could be confirmed by differential detergent extraction. The observed redistribution of 27E10 antigen guided by collagen compared with fibronectin was also paralleled by an augmented release of inflammatory cytokines interleukin-6, tumor necrosis factor alpha, and superoxide anions. Thus, this study demonstrates that under inflammatory conditions the interactions of extravasating monocytes with the ECM may induce an activated phenotype of monocytes marked by 27E10.

Adherence of human monocytes to haemodialysis membranes

In the present study we evaluated spontaneous and stimulated adherence of human monocytes to regenerated cellulose and polyacrylonitrile (AN69) membranes. Spontaneous adherence at 60 min was significantly higher for regenerated cellulose (28 +/- 2%, P < 0.001) than for AN69 (11 +/- 2) membranes. Stimuli such as bacterial lipopolysaccharide, TNF alpha, interleukin-1 and -6 as well as platelet-activating factor, but not IL-4, significantly enhanced adherence at 60 min to AN69 (28 to 30%). In contrast, adherence was not further inducible in the presence of regenerated cellulose. Both spontaneous and cytokine/bacterial lipopolysaccharide-stimulated adherence were significantly reduced by SDZ-63072, a specific platelet-activating factor receptor antagonist. This difference in sensitivity of monocyte adherence reflects probably the intrinsic ability of regenerated cellulose to provide maximal spontaneous monocyte adhesion. These data suggest that PAF may act as an adherence mediator. This is in line with the ability of regenerated cellulose to directly stimulate monocytes to synthesize platelet-activating factor and with the ability of cytokines and bacterial lipopolysaccharide to stimulate its synthesis. Although AN69 has a low adherence potential, bacterial lipopolysaccharide or cytokines may blunt the biocompatibility of this membrane.

On the spontaneous adherence of myelin basic protein to T lymphocytes

We have applied a double tagging system in order to study whether purified myelin basic protein is able to adhere to normal human peripheral T lymphocytes without the need to purify cells. Evaluation of myelin basic protein adherence to peripheral blood mononuclear cells was determined with biotinylated myelin basic protein and fluoresceinated avidin, and lymphocyte population was identified by the corresponding phycoerythrinated monoclonal antibody. The observed adherence of myelin basic protein to T lymphocytes was found to depend on protein conformation.

Reduced antibody-dependent cellular cytotoxicity to herpes simplex virus-infected cells of salivary polymorphonuclear leukocytes and inhibition of peripheral blood polymorphonuclear leukocyte cytotoxicity by saliva.

Blood polymorphonuclear leukocytes (BPMN) have been shown to mediate antibody-dependent cellular cytotoxicity (ADCC) against HSV-infected cells. Although HSV infections are frequently found in the oral cavity, the ADCC capacity of salivary PMN (SPMN) has not been studied, mainly because methods to isolate SPMN were not available. We have recently developed a method to isolate SPMN, and in this study have evaluated their ADCC activity against HSV-infected cells. SPMN were obtained by repeated washings of the oral cavity, and separated from epithelial cells by nylon mesh filtration. ADCC was quantitatively determined by 51Cr release from HSV-infected Chang liver cells. SPMN in the presence of antibody were able to destroy HSV-infected cells, but SPMN were much less effective in mediating ADCC than BPMN (3.4% vs 40.7%, p less than 0.0001). In the presence of antiviral antibody, SPMN were able to adhere to HSV-infected cells, but less so than BPMN (34% vs 67%), and specific antibody-induced adherence was significantly lower in SPMN (p less than 0.04). The spontaneous adherence to HSV-infected cells was higher for SPMN than BPMN. SPMN demonstrated up-regulation of the adhesion glycoprotein CD18, but down-regulation of the FcRIII receptor. Incubation with saliva decreased ADCC capacity of BPMN, up-regulated CD18 expression, and down-regulated FcRIII expression.

Peroxidative stress and in vitro ageing of endothelial cells increases the monocyte-endothelial cell adherence in a human in vitro system

Adherence of monocytes to the endothelium is an early event in atherogenesis. Changes in the endothelium are probably involved in this process. We have investigated the influence of peroxidative stress and in vitro ageing of endothelial cells on the subsequent adherence of monocytes using an in vitro system. Treatment of young human umbilical vein endothelial cells (HUVEC) with 60 μM cumene hydroperoxide (Clip) resulted in a 2.1-fold increase in monocyte adherence. This increase was not dependent on de novo synthesis of membrane antigens. No such increase upon Chp treatment was observed using young human umbilical artery endothelial cells (HUAEC) and in vitro aged HUVEC and HUAEC. As compared with “young” HUVEC, a higher spontaneous adherence of monocytes to “young” HUAEC (1.8 times), “aged” HUVEC (2.5 times) and “aged” HUAEC (2.7 times) was observed. Furthermore, fibroblasts showed an about 3 times higher monocyte adherence, whereas an 8 times higher adherence was observed to endothelial extracellular matrix. These data suggest that the spontaneous monocyte adherence to “young”, intact endothelium can be increased by peroxidative damaging and by ageing of the endothelial cells. A denudation and subsequent exposure of the extracellular matrix may further stimulate this process. The possible physiological vector for endothelial peroxidation is discussed.

Human monocyte adherence: a primary effect of chemotactic factors on the monocyte to stimulate adherence to human endothelium.

Monocyte emigration into areas of inflammation is initiated by monocyte adherence to the microvascular endothelium which may be induced by the local production of chemotactic factors at the inflammatory site. However, it is not clear whether such stimuli act on the monocyte and/or the endothelial cell to promote this effect. Accordingly, the effect of the chemotactic peptides C5a des arg and formyl-methionyl-leucyl-phenylalanine (FMLP) on human monocyte adherence to human microvascular endothelial cell monolayers was investigated in vitro. Monocytes (92 to 98% pure) were isolated by discontinuous plasma-Percoll density gradients and cell elutriation, methods designed to minimize monocyte exposure to endotoxin. Mean spontaneous (unstimulated) adherence of 111Indium-tropolonate-radiolabeled monocytes to microvascular endothelial cell monolayers was 19.7% +/- 1.3. Monocyte adherence to microvascular endothelial cell monolayers was stimulated in a dose-response fashion in the presence of C5a des arg or FMLP to a maximum mean adherence of 47.2% +/- 2.9 or 43.8% +/- 2.2, respectively. C5a des arg or FMLP stimulated monocytes to adhere to monolayers of human vascular smooth muscle cells, human dermal fibroblasts, or serum-coated plastic wells in a comparable fashion as to endothelial cells. The simultaneous presence of both chemotactic peptides C5a des arg and FMLP in the assay system stimulated monocyte adherence to the same degree as either stimulus alone. This finding suggested that those monocytes stimulated to adhere by C5a des arg were the same subpopulation responding to FMLP. Spontaneous monocyte adherence (in the absence of chemotactic peptides) to both endothelial cell monolayers and serum-coated plastic wells was reduced in the presence of plasma, but chemotactic peptides induced a significant, albeit reduced, adhesion of monocytes in this circumstance. The pretreatment of monocytes with either C5a des arg or FMLP prior to the adherence assay induced stimulus-specific desensitization of monocyte adherence. Neither a desensitization nor stimulated monocyte adherence occurred when endothelial cell monolayers or serum-coated plastic wells were pretreated with either of the chemotactic peptides. The fixation of endothelial cell monolayers prior to the adherence assay did not alter the degree of spontaneous, C5a des arg-stimulated, or FMLP-stimulated monocyte adherence. These data suggest that the stimulated adhesion of monocytes to endothelial cells by C5a des arg or FMLP represents primarily an effect of these chemotactic peptides on the monocyte.