Ambush strategy enhances organisms' performance in rock-paper-scissors games

We study a five-species cyclic system wherein individuals of one species strategically adapt their movements to enhance their performance in the spatial rock-paper-scissors game. Environmental cues enable the awareness of the presence of organisms targeted for elimination in the cyclic game. If the local density of target organisms is sufficiently high, individuals move towards concentrated areas for direct attack; otherwise, they employ an ambush tactic, maximising the chances of success by targeting regions likely to be dominated by opponents. Running stochastic simulations, we discover that the ambush strategy enhances the likelihood of individual success compared to direct attacks alone, leading to uneven spatial patterns characterised by spiral waves. We compute the autocorrelation function and measure how the ambush tactic unbalances the organisms' spatial organisation by calculating the characteristic length scale of typical spatial domains of each species. We demonstrate that the threshold for local species density influences the ambush strategy's effectiveness, while the neighbourhood perception range significantly impacts decision-making accuracy. The outcomes show that long-range perception improves performance by over 60%, although there is potential interference in decision-making under high attack triggers. Understanding how organisms' adaptation their environment enhances their performance may be helpful not only for ecologists, but also for data scientists, aiming to improve artificial intelligence systems.

Dynamics of blaOXA-23 gene transmission in Acinetobacter spp. from contaminated veterinary environmental surfaces: an emerging One Health threat?

BACKGROUND

Carbapenem-resistant Acinetobacter baumannii is a common pathogen associated with healthcare-acquired infections, and robust infection prevention and control protocols exist in human healthcare settings. In contrast, infection prevention and control (IPC) standards are limited in veterinary medicine, necessitating further investigation.

AIM

Examine the possible transmission of carbapenem-resistant Acinetobacter spp. in a veterinary practice where a cat was diagnosed with an OXA-23-producing A. baumannii ST2 strain.

METHODS

Environmental samples together with nasal and hand swabs from the veterinary personnel were collected. All swabs were screened for the presence of extended-spectrum-β-lactamase- and carbapenemase-producing Enterobacterales, meticillin-resistant staphylococcus and multi-drug-resistant Acinetobacter spp. Whole-genome sequencing was performed for carbapenemase-producing strains.

RESULTS

Of the veterinary staff, 60% carried meticillin-resistant Staphylococcus epidermidis. Environmental evaluation showed that 40% (N=6/15) of the surfaces analysed by contact plates and 40% (N=8/20) by swabs failed the hygiene criteria. Assessment of the surfaces revealed contamination with five OXA-23-producing Acinetobacter spp. strains: an OXA-23-producing Acinetobacter schindleri on the weight scale in the waiting room; and four OXA-23-producing Acinetobacter lwoffii strains, on different surfaces of the treatment room. The blaOXA-23 gene was located on the same plasmid-carrying Tn2008 across the different Acinetobacter spp. strains. These plasmids closely resemble a previously described OXA-23-encoding plasmid from a human Portuguese nosocomial Acinetobacter pittii isolate. Distinctly, the OXA-23-producing A. baumannii ST2 clinical strain had the resistant gene located on Tn2006, possibly inserted on the chromosome.

CONCLUSION

The detection of an OXA-23-producing A. baumannii ST2 veterinary clinical strain is of concern for companion animal health and infection, prevention and control. This study established the dynamic of transmission of the plasmid-mediated blaOXA-23 gene on critical surfaces of a small animal veterinary practice. The genetic resemblance to a plasmid found in human nosocomial settings suggests a potential One Health link.

Chronic pain after breast surgery: incidence, risk factors and impact on quality of life

INTRODUCTION AND OBJECTIVES

Breast cancer is the most frequently diagnosed malignancy, and chronic pain after breast surgery (CPBS) is an increasingly recognized therapy-related problem. We evaluated CPBS incidence, characteristics, associated factors, and impact on patient quality of life (QoL).

MATERIALS AND METHODS

Six-month observational prospective study conducted in patients undergoing breast surgery in a tertiary university hospital. Data were collected using several questionnaires: Pain Catastrophizing Scale, Brief Pain Inventory-Short Form, Douleur Neuropathique 4 Questionnaire, and European Organization for Research and Treatment of Cancer Quality of Life Questionnaire and its Breast Cancer Module.

RESULTS

A total of 112 patients completed the study. Approximately, one third (34.8%) developed CPBS, and almost all with potentially neuropathic pain. CPBS interfered with patients' daily life and reduced their QoL. Diabetes (p = 0.028), catastrophizing (p = 0.042), and acute postoperative pain severity (p < 0.001) were associated with CPBS.

CONCLUSIONS

This study broadens our understanding of CPBS and shows the impact of this syndrome. Healthcare workers need to be aware of CPBS and take steps to prevent and treat it, and provide patients with adequate information.

Spatial dynamics of synergistic coinfection in rock-paper-scissors models

We investigate the spatial dynamics of two-disease epidemics reaching a three-species cyclic model. Regardless of their species, all individuals are susceptible to being infected with two different pathogens, which spread through person-to-person contact. We consider that the simultaneous presence of multiple infections leads to a synergistic amplification in the probability of host mortality due to complications arising from any of the co-occurring diseases. Employing stochastic simulations, we explore the ramifications of this synergistic coinfection on spatial configurations that emerge from stochastic initial conditions. Under conditions of pronounced synergistic coinfection, we identify the emergence of zones inhabited solely by hosts affected by a singular pathogen. At the boundaries of spatial domains dominated by a single disease, interfaces of coinfected hosts appear. The dynamics of these interfaces are shaped by curvature-driven processes and display a scaling behavior reflective of the topological attributes of the underlying two-dimensional space. As the lethality linked to coinfection diminishes, the evolution of the interface network's spatial dynamics is influenced by fluctuations stemming from waves of coinfection that infiltrate territories predominantly occupied by a single disease. Our analysis extends to quantifying the implications of synergistic coinfection at both the individual and population levels Our outcomes show that organisms' infection risk is maximized if the coinfection increases the death due to disease by 30% and minimized as the network dynamics reach the scaling regime, with species populations being maximum. Our conclusions may help ecologists understand the dynamics of epidemics and their impact on the stability of ecosystems.

Locally adaptive aggregation of organisms under death risk in rock-paper-scissors models

We run stochastic simulations of the spatial version of the rock-paper-scissors game, considering that individuals use sensory abilities to scan the environment to detect the presence of enemies. If the local dangerousness level is above a tolerable threshold, individuals aggregate instead of moving randomly on the lattice. We study the impact of the locally adaptive aggregation on the organisms' spatial organisation by measuring the characteristic length scale of the spatial domains occupied by organisms of a single species. Our results reveal that aggregation is beneficial if triggered when the local density of opponents does not exceed 30%; otherwise, the behavioural strategy may harm individuals by increasing the average death risk. We show that if organisms can perceive further distances, they can accurately scan and interpret the signals from the neighbourhood, maximising the effects of the locally adaptive aggregation on the death risk. Finally, we show that the locally adaptive aggregation behaviour promotes biodiversity independently of the organism's mobility. The coexistence probability rises if organisms join conspecifics, even in the presence of a small number of enemies. We verify that our conclusions hold for more complex systems by simulating the generalised rock-paper-scissors models with five and seven species. Our discoveries may be helpful to ecologists in understanding systems where organisms' self-defence behaviour adapts to local environmental cues.

Marine Natural Products in the Battle against Dengue, Zika, and Chikungunya Arboviruses

Arthropod-borne viruses (arboviruses) are a severe public health problem worldwide, consisting of a significant part of all the emerging infectious diseases. It is estimated that arboviruses infect hundreds of millions of people globally each year, resulting in several thousand deaths. Despite their clear health threat, there are no prophylactic or pharmacological therapies available for most of them. Control of arbovirus infections is beyond pharmacological options; handling the larvae of mosquitos is an important and successful strategy, although currently available insecticides and larvicides are already associated with resistance. Therefore, searching for new strategies to prevent arbovirus infection is urgent and necessary. Marine organisms are an excellent source for structurally novel compounds due to their unique secondary metabolism, with outstanding antiviral and larvicidal activities. In the present review, we explored the ability of various marine natural products (MNPs) such as indole derivatives, diketopiperazines, scequinadoline A, cyclohexadepsipeptides, and others, to act as both antiviral and larvicidal, in an attempt to highlight their structure activity potential against the most relevant arboviruses affecting the human health.

How local antipredator response unbalances the rock-paper-scissors model

Antipredator behavior is a self-preservation strategy present in many biological systems, where individuals join the effort in a collective reaction to avoid being caught by an approaching predator. We study a nonhierarchical tritrophic system, whose predator-prey interactions are described by the rock-paper-scissors game rules. We perform a set of spatial stochastic simulations where organisms of one out of the species can resist predation in a collective strategy. The drop in predation capacity is local, which means that each predator faces a particular opposition depending on the prey group size surrounding it. Considering that the interference in a predator action depends on the prey's physical and cognitive ability, we explore the role of a conditioning factor that indicates the fraction of the species apt to perform the antipredator strategy. Because of the local unbalancing of the cyclic predator-prey interactions, departed spatial domains mainly occupied by a single species emerge. Unlike the rock-paper-scissors model with a weak species because of a nonlocal reason, our findings show that if the predation probability of one species is reduced because individuals face local antipredator response, the species does not predominate. Instead, the local unbalancing of the rock-paper-scissors model results in the prevalence of the weak species' prey. Finally, the outcomes show that local unevenness may jeopardize biodiversity, with the coexistence being more threatened for high mobility.

Spatial organisation plasticity reduces disease infection risk in rock-paper-scissors models

We study a three-species cyclic game system where organisms face a contagious disease whose virulence may change by a pathogen mutation. As a responsive defence strategy, organisms' mobility is restricted to reduce disease dissemination in the system. The impact of the collective self-preservation strategy on the disease infection risk is investigated by performing stochastic simulations of the spatial version of the rock-paper-scissors game. Our outcomes show that the mobility control strategy induces plasticity in the spatial patterns with groups of organisms of the same species inhabiting spatial domains whose characteristic length scales depend on the level of dispersal restrictions. The spatial organisation plasticity allows the ecosystems to adapt to minimise the individuals' disease contamination risk if an eventual pathogen alters the disease virulence. We discover that if a pathogen mutation makes the disease more transmissible or less lethal, the organisms benefit more if the mobility is not strongly restricted, thus forming large spatial domains. Conversely, the benefits of protecting against a pathogen causing a less contagious or deadlier disease are maximised if the average size of groups of individuals of the same species is significantly limited, reducing the dimensions of groups of organisms significantly. Our findings may help biologists understand the effects of dispersal control as a conservation strategy in ecosystems affected by epidemic outbreaks.

Mobility-limiting antipredator response in the rock-paper-scissors model

Antipredator behavior is present in many biological systems where individuals collectively react to an imminent attack. The antipredator response may influence spatial pattern formation and ecosystem stability but requires an organism's cost to contribute to the collective effort. We investigate a nonhierarchical tritrophic system, whose predator-prey interactions are described by the rock-paper-scissors game rules. In our spatial stochastic simulations, the radius of antipredator response defines the maximum prey group size that disturbs the predator's action, determining the individual cost to participate in antipredator strategies. We consider that each organism contributes equally to the collective effort, having its mobility limited by the proportion of energy devoted to the antipredator reaction. Our outcomes show that the antipredator response leads to spiral patterns, with the segregation of organisms of the same species occupying departed spatial domains. We found that a less localized antipredator response increases the average size of the single-species patches, improving the protection of individuals against predation. Finally, our findings show that although the increase of the predation risk for a more localized antipredator response, the high mobility constraining benefits species coexistence. Our results may help ecologists understand the mechanisms leading to the stability of biological systems where locality is crucial to behavioral interactions among species.

First-line nivolumab plus ipilimumab with two cycles of chemotherapy versus chemotherapy alone (four cycles) in advanced non-small-cell lung cancer: CheckMate 9LA 2-year update

BACKGROUND

To further characterize survival benefit with first-line nivolumab plus ipilimumab with two cycles of chemotherapy versus chemotherapy alone, we report updated data from the phase III CheckMate 9LA trial with a 2-year minimum follow-up.

PATIENTS AND METHODS

Adult patients were treatment naïve, with stage IV/recurrent non-small-cell lung cancer, no known sensitizing EGFR/ALK alterations, and an Eastern Cooperative Oncology Group performance status ≤1. Patients were randomized 1 : 1 to nivolumab 360 mg every 3 weeks plus ipilimumab 1 mg/kg every 6 weeks with two cycles of chemotherapy, or four cycles of chemotherapy. Updated efficacy and safety outcomes are reported, along with progression-free survival (PFS) after next line of treatment (PFS2), treatment-related adverse events (TRAEs) by treatment cycle, and efficacy outcomes in patients who discontinued all treatment components in the experimental arm due to TRAEs.

RESULTS

With a median follow-up of 30.7 months, nivolumab plus ipilimumab with chemotherapy continued to prolong overall survival (OS) versus chemotherapy. Median OS was 15.8 versus 11.0 months [hazard ratio 0.72 (95% confidence interval 0.61-0.86)]; 2-year OS rate was 38% versus 26%. Two-year PFS rate was 20% versus 8%. ORR was 38% versus 25%, respectively; 34% versus 12% of all responses were ongoing at 2 years. Median PFS2 was 13.9 versus 8.7 months. Improved efficacy outcomes in the experimental versus control arm were observed across most subgroups, including by programmed death-ligand 1 and histology. No new safety signals were observed; onset of grade 3/4 TRAEs was mostly observed during the first two treatment cycles in the experimental arm. In patients who discontinued all components of nivolumab plus ipilimumab with chemotherapy treatment due to TRAEs (n = 61) median OS was 27.5 months; 56% of responders had an ongoing response ≥1 year after discontinuation.

CONCLUSIONS

With a 2-year minimum follow-up, nivolumab plus ipilimumab with two cycles of chemotherapy provided durable efficacy benefits over chemotherapy with a manageable safety profile and remains an efficacious first-line treatment of advanced non-small-cell lung cancer.

Antipredator behavior in the rock-paper-scissors model

When faced with an imminent risk of predation, many animals react to escape consumption. Antipredator strategies are performed by individuals acting as a group to intimidate predators and minimize the damage when attacked. We study the antipredator prey response in spatial tritrophic systems with cyclic species dominance using the rock-paper-scissors game. The impact of the antipredator behavior is local, with the predation probability reducing exponentially with the number of prey in the predator's neighborhood. In contrast to the standard Lotka-Volterra implementation of the rock-paper-scissors model, where no spiral waves appear, our outcomes show that the antipredator behavior leads to spiral patterns from random initial conditions. The results show that the predation risk decreases exponentially with the level of antipredator strength. Finally, we investigate the coexistence probability and verify that antipredator behavior may jeopardize biodiversity for high mobility. Our findings may help biologists to understand ecosystems formed by species whose individuals behave strategically to resist predation.

Behavioural movement strategies in cyclic models

The spatial segregation of species is fundamental to ecosystem formation and stability. Behavioural strategies may determine where species are located and how their interactions change the local environment arrangement. In response to stimuli in the environment, individuals may move in a specific direction instead of walking randomly. This behaviour can be innate or learned from experience, and allow the individuals to conquer or the maintain territory, foraging or taking refuge. We study a generalisation of the spatial rock-paper-scissors model where individuals of one out of the species may perform directional movement tactics. Running a series of stochastic simulations, we investigate the effects of the behavioural tactics on the spatial pattern formation and the maintenance of the species diversity. We also explore a more realistic scenario, where not all individuals are conditioned to perform the behavioural strategy or have different levels of neighbourhood perception. Our outcomes show that self-preservation behaviour is more profitable in terms of territorial dominance, with the best result being achieved when all individuals are conditioned and have a long-range vicinity perception. On the other hand, invading is more advantageous if part of individuals is conditioned and if they have short-range neighbourhood perception. Finally, our findings reveal that the self-defence strategy is the least jeopardising to biodiversity which can help biologists to understand population dynamics in a setting where individuals may move strategically.

Expanding spatial domains and transient scaling regimes in populations with local cyclic competition

We investigate a six-species class of May-Leonard models leading to the formation of two types of competing spatial domains, each one inhabited by three species with their own internal cyclic rock-paper-scissors dynamics. We study the resulting population dynamics using stochastic numerical simulations in two-dimensional space. We find that as three-species domains shrink, there is an increasing probability of extinction of two of the species inhabiting the domain, with the consequent creation of one-species domains. We determine the critical initial radius beyond which these one-species spatial domains are expected to expand. We further show that a transient scaling regime, with a slower average growth rate of the characteristic length scale L of the spatial domains with time t, takes place before the transition to a standard L∝t^{1/2} scaling law, resulting in an extended period of coexistence.

How directional mobility affects coexistence in rock-paper-scissors models

This work deals with a system of three distinct species that changes in time under the presence of mobility, selection, and reproduction, as in the popular rock-paper-scissors game. The novelty of the current study is the modification of the mobility rule to the case of directional mobility, in which the species move following the direction associated to a larger (averaged) number density of selection targets in the surrounding neighborhood. Directional mobility can be used to simulate eyes that see or a nose that smells, and we show how it may contribute to reduce the probability of coexistence.

Effects of low doses of mifepristone on human embryo implantation process in a three-dimensional human endometrial in vitro co-culture system

OBJECTIVES

We wanted to explore the effects of two different low doses (0.5μM and 0.05μM) of mifepristone, exposed during the receptive period, on the human embryo implantation process, using a well-established three-dimensional in vitro cell culture model, specifically developed to study this process.

METHODS

An in vitro three-dimensional cell culture model was constructed using human endometrial cells isolated from the endometrium of proven fertile women, collected on cycle day LH+4. After 5 days of culture, supernumerary human embryos were added and cultured for another 5 days with mifepristone 0.5μM (n=8) or 0.05μM (n=10) or vehicle as control (n=10). The cultures were checked for embryo attachment and terminated. We studied the expression of 16 reported endometrial receptivity markers in the endometrial constructs using real-time polymerase chain reaction.

RESULTS

None of the embryos in 0.5μM of mifepristone attached to the endometrial constructs (p=.004), whereas 4 out of 10 in 0.05μM (p=.3698) and 7 out of 10 embryos in the control group attached to the cultures. We found that most of the studied receptivity markers were significantly altered with mifepristone exposure in a similar direction in both treatment groups. Only IL6 was significantly differentially expressed between the treatment groups (p=.017).

CONCLUSION

We report for the first time that exposure to a low concentration (0.5μM) of mifepristone during the receptive period successfully inhibits human embryo implantation process in vitro. Further, we observed a dose-dependent effect of mifepristone on endometrial receptivity at the functional level.

IMPLICATION

This study contributes new knowledge that low dose of mifepristone during the short period of receptive phase can inhibit endometrial receptivity, which further promotes mifepristone as a contraceptive agent. This could give women a treatment choice to avoid unwanted pregnancy with high efficacy and minimal side effects.

Effects of ulipristal acetate on human embryo attachment and endometrial cell gene expression in an in vitro co-culture system

STUDY QUESTION

Does ulipristal acetate (UPA) used for emergency contraception (EC) interfere with the human embryo implantation process?

SUMMARY ANSWER

UPA, at the dosage used for EC, does not affect human embryo implantation process, in vitro.

WHAT IS KNOWN ALREADY

A single pre-ovulatory dose of UPA (30 mg) acts by delaying or inhibiting ovulation and is recommended as first choice among emergency contraceptive pills due to its efficacy. The compound has also been demonstrated to have a dose-dependent effect on the endometrium, which theoretically could impair endometrial receptivity but its direct action on human embryo implantation has not yet been studied.

STUDY DESIGN, SIZE, DURATION

Effect of UPA on embryo implantation process was studied in an in vitro endometrial construct. Human embryos were randomly added to the cultures and cultured for 5 more days with UPA (n = 10) or with vehicle alone (n = 10) to record the attachment of embryos.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Endometrial biopsies were obtained from healthy, fertile women on cycle day LH+4 and stromal and epithelial cells were isolated. A three-dimensional in vitro endometrial co-culture system was constructed by mixing stromal cells with collagen covered with a layer of epithelial cells and cultured in progesterone containing medium until confluence. The treatment group received 200 ng/ml of UPA. Healthy, viable human embryos were placed on both control and treatment cultures. Five days later the cultures were tested for the attachment of embryos and the 3D endometrial constructs were analysed for endometrial receptivity markers by real-time PCR.

MAIN RESULTS AND THE ROLE OF CHANCE

There was no significant difference in the embryo attachment rate between the UPA treated group and the control group as 5 out of 10 human embryos exposed to UPA and 7 out of 10 embryos in the control group attached to the endometrial cell surface (P = 0.650). Out of 17 known receptivity genes studied here, only 2 genes, HBEGF (P = 0.009) and IL6 (P = 0.025) had a significant up-regulation and 4 genes, namely HAND2 (P = 0.003), OPN (P = 0.003), CALCR (P = 0.016) and FGF2 (P = 0.023) were down-regulated with the exposure of UPA, compared with control group.

LIMITATIONS, REASONS FOR CAUTION

This proof of concept study was conducted with a few human embryos, as their availability was limited. Although the 3D model used for this study is well established and the artificial endometrial luminal epithelium shown to express progesterone regulated markers of endometrial receptivity it is still an in vitro model, lacking all cell types that constitute the receptive endometrium in vivo.

WIDER IMPLICATIONS OF THE FINDINGS

This study provides new insights on the mechanism of action of UPA on human embryo implantation, demonstrating that UPA in a dosage used for EC does not affect embryo viability and the implantation process of embryo. Progesterone receptor modulators (PRMs) hold the potential to be attractive estrogen- and gestagen-free contraceptives and thus may be made available to a larger proportion of women globally due to these findings.

STUDY FUNDING/COMPETING INTERESTS

Swedish Research Council (K2010-54X-14212-09-3) and support provided through the regional agreement on medical training and clinical research (ALF) between Stockholm County Council and Karolinska University Hospital.

Interfaces with internal structures in generalized rock-paper-scissors models

In this work we investigate the development of stable dynamical structures along interfaces separating domains belonging to enemy partnerships in the context of cyclic predator-prey models with an even number of species N≥8. We use both stochastic and field theory simulations in one and two spatial dimensions, as well as analytical arguments, to describe the association at the interfaces of mutually neutral individuals belonging to enemy partnerships and to probe their role in the development of the dynamical structures at the interfaces. We identify an interesting behavior associated with the symmetric or asymmetric evolution of the interface profiles depending on whether N/2 is odd or even, respectively. We also show that the macroscopic evolution of the interface network is not very sensitive to the internal structure of the interfaces. Although this work focuses on cyclic predator-prey models with an even number of species, we argue that the results are expected to be quite generic in the context of spatial stochastic May-Leonard models.

von Neummann's and related scaling laws in rock-paper-scissors-type games

We introduce a family of rock-paper-scissors-type models with Z(N) symmetry (N is the number of species), and we show that it has a very rich structure with many completely different phases. We study realizations that lead to the formation of domains, where individuals of one or more species coexist, separated by interfaces whose (average) dynamics is curvature driven. This type of behavior, which might be relevant for the development of biological complexity, leads to an interface network evolution and pattern formation similar to the ones of several other nonlinear systems in condensed matter and cosmology.

Junctions and spiral patterns in generalized rock-paper-scissors models

We investigate the population dynamics in generalized rock-paper-scissors models with an arbitrary number of species N. We show that spiral patterns with N arms may develop both for odd and even N, in particular in models where a bidirectional predation interaction of equal strength between all species is modified to include one N-cyclic predator-prey rule. While the former case gives rise to an interface network with Y-type junctions obeying the scaling law L∝t1/2, where L is the characteristic length of the network and t is the time, the latter can lead to a population network with N-armed spiral patterns, having a roughly constant characteristic length scale. We explicitly demonstrate the connection between interface junctions and spiral patterns in these models and compute the corresponding scaling laws. This work significantly extends the results of previous studies of population dynamics and could have profound implications for the understanding of biological complexity in systems with a large number of species.

Herpes simplex virus-1 infection of colonic explants as a model of viral-induced activation of Crohn's disease

The exogenous triggers responsible for Crohn's disease (CD) relapses are not often identified. Cytomegalovirus and other members of the herpesvirus family have been implicated in precipitating relapses. However, the role of viral infections in the immunopathogenesis of CD remains poorly understood. We describe an ex-vivo model of primary viral infection of CD tissue with Herpes Simplex Virus type I (HSV-1). IL-6 and CD68 served as markers for CD inflammation, type I IFNs for viral infection. Colonic explants obtained from CD resections were infected via the luminal or the submucosal compartments with HSV-1 or mock virus solution, at varying concentrations for up to 20 h. Serial tissue sections were assayed for expression of HSV-1 specific antigens, CD-68, IL-6 and DC-SIGN. Culture supernatants were tested for IL-6 and type I IFN production. Positive immunostaining for HSV-1 specific antigens was consistently detectable using 11×10(6)PFU from 13 h onwards, mainly on cells located in the submucosa, and in the perivascular area. CD68 was up-regulated in lamina propria macrophages from mildly and non-inflamed CD tissue after HSV-1 infection. IL-6+ cells in the infected tissues were mainly submucosal DC-SIGN+ dendritic cells. IL-6 and IFN-β levels were higher in the supernatants from HSV-1-infected explants compared to controls after 20 h of culture (p<0.01). These data show increased expression of inflammatory markers during the initial stages of HSV-1 primary infection using CD colonic explants. This in vitro model appears promising to study the immunoregulatory changes induced by microbial infection in reactivation of CD.

Analyses of the prognostic significance of the Epstein-Barr virus transactivator ZEBRA protein and diagnostic value of its two synthetic peptides in nasopharyngeal carcinoma

BACKGROUND

Although numerous serological studies have determined the diagnostic and prognostic values of Epstein-Barr virus (EBV) antibodies in adult patients with nasopharyngeal carcinoma (NPC), little data about the anti-EBV immune response in children with NPC is available.

OBJECTIVES

To examine the diagnostic value of IgG antibodies against BamHI Z Epstein-Barr replication activator (ZEBRA) protein and two related synthetic peptides (Zp125 and Zp130). To compare the prognostic value of IgA antibodies against early antigens (EA) and viral capsid antigen (VCA), and IgG antibodies against ZEBRA protein, of Moroccan children treated for NPC with their prognostic value for young and adult NPC patients.

STUDY DESIGN

Sera were collected from 255 newly diagnosed Moroccan NPC patients and 226 healthy donors. IgA antibody against VCA and EA was measured by immunofluorescence assays. IgG antibody against ZEBRA, Zp125, and Zp130 was measured by ELISA.

RESULTS

No significant difference in the detection of IgG-Zp125 and Zp130 antibodies was observed in children with NPC. IgG-Zp130 were detected less frequently than IgG-Zp125 in young and adult patients, as compared to children. High specificity of IgG-Zp125 and -Zp130 antibodies was found in the three age groups. A decrease in IgG-ZEBRA was observed in patients with NPC in clinical remission, whereas patients with NPC who died or developed metastases maintained or had an increase in these titers.

CONCLUSION

IgG-ZEBRA is a better diagnostic and post-therapeutic prognostic marker in children with NPC, who showed very low titers of IgA -VCA and -EA.

Herpes simplex virus-1 up-regulates IL-15 gene expression in monocytic cells through the activation of protein tyrosine kinase and PKC zeta/lambda signaling pathways

IL-15 plays a seminal role in innate immunity through enhancing the cytotoxic function as well as cytokine production by NK and T cells. We have previously shown that exposure of PBMC as well as monocytic cells to different viruses results in immediate up-regulation of IL-15 gene expression and subsequent NK cell activation as an innate immune response of those cells to these viruses. However, no signaling pathway involved in this up-regulation has been identified. Here we show for the first time that HSV-1-induced up-regulation of IL-15 gene expression is independent of viral infectivity/replication. IL-15 gene is up-regulated by HSV-1 in human monocytes, but not in CD3+ T cells. HSV-1 induces the phosphorylation of protein tyrosine kinases (PTKs) and protein kinase C (PKC) for inducing IL-15 expression in monocytic cells. Inhibitors for PTKs reduced HSV-1-induced PTK activity, DNA binding activity of NF-kB as well as IL-15 gene expression. In contrast, an inhibitor for membrane-bound tyrosine kinases had no effect on these events. Experiments using PKC inhibitors revealed that phosphorylation of PKC zeta/lambda (PKC zeta/lambda), DNA binding activity of NF-kB and HSV-1-induced up-regulation of IL-15 were all decreased. Furthermore, we found that HSV-1-induced IL-15 up-regulation was also dependent on PTKs regulation of PKC phosphorylation. Thus, we conclude that IL-15 up-regulation in HSV-1-treated monocytic cells is dependent on the activity of both PTKs and PKC zeta/lambda.

Interaction of monocytic cells with respiratory syncytial virus results in activation of NF-kappaB and PKC-alpha/beta leading to up-regulation of IL-15 gene expression

Respiratory syncytial virus (RSV) is a major human respiratory pathogen, particularly for infants. RSV is also a powerful inducer of cytokines, one of which is IL-15, an important immunoregulatory cytokine. IL-15 plays a key role in NK and T cell development and differentiation and also regulates NK cell/macrophage interaction, as well as monocyte/macrophage and granulocyte function. We have shown previously that different viruses up-regulate IL-15 gene expression in human PBMCs. Recently, we found that RSV induces the expression of IL-15 mRNA in the monocytic line THP-1. The signaling pathway involved in such virus-induced up-regulation of IL-15 has not yet been identified. We report here a study describing this mechanism. Because of the involvement of the protein kinase C (PKC) and the transcription factor NF-kappaB in the regulation of others cytokines by RSV as well as the involvement of NF-kappaB in the transactivation of IL-15, our hypothesis was that RSV induced the expression of IL-15 in THP-1 cells through the PKC and NF-kappaB activation. We demonstrate here that RSV-induced up-regulation of IL-15 expression in THP-1 cells involves the phosphorylation of PKC-alpha/beta. Further, inhibition of PKC by different specific inhibitors blocks this up-regulation. Using the electromobility shift assay, we show that the activated form of NF-kappaB binds to the IL-15 promoter sequence. We further confirm, using an ELISA assay, the involvement of p65 in the transcription of IL-15. This study, demonstrating the ability of RSV to induce IL-15 expression, might explain, at least in part, the exacerbated, inflammatory response triggered by RSV infection.