Dynamics Of Leukocytes Research Articles

Distinctive features associated with differentiation syndrome in acute promyelocytic leukemia in patients treated by all-trans retinoic acid and arsenic trioxide

In acute promyelocytic leukemia (APL), the combination treatment of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) appears to have a synergistic effect. Due to this synergism, differentiation syndrome (DS) in APL assumes a distinct identity separate from the formerly known ATRA syndrome, with distinct temporal patterns, diagnostic parameters, and clinical behavior. We retrospectively evaluated single-center data of years 2013–2022. Patients with newly diagnosed APL were categorized into three groups (16 patients in ATRA/ATO standard-risk group, 3 patients in ATRA/chemotherapy standard-risk group, and 5 patients in ATRA/chemotherapy high-risk group). Our aim was to analyze leukocytosis, signs of DS, and hepatic impairment within the first 25 days of treatment. The incidence of DS in the ATRA/ATO SR group was 43.8 %, with a median of 4 days and 2 days from ATRA and ATO initiation, respectively. This group also exhibited higher peak levels of leukocytosis 34.5 (6.0–113.4) x109/L (p = 0.0809). ALT elevation was more prevalent in the ATRA/ATO SR group (93.75 %), with 68.75 % grade 3–4 elevations (p = 0.0094). Importantly, all patients in this group had ALT levels that returned to normal during the subsequent consolidations. These findings suggest hepatopathy as a potential manifestation of ATRA/ATO induced leukocyte differentiation and/or DS. Diverse differentiation patterns were identified within the ATRA/ATO group, classifying patients into three distinct subgroups based on the concurrent dynamics of leukocytes and ALT levels, illustrating simultaneous, sequential, and divergent elevation patterns. These emphasize the different distribution of differentiation (organs vs. peripheral blood). We introduced real-world data and advocated for reevaluation of the current DS definition and associated diagnostic thresholds. Our study, conducted in a small country with a limited number of APL patients, acknowledges the inherent constraints in sample size. Further investigations with larger patient cohorts are warranted to validate and reinforce the outcomes observed in our study.

Frequencies of activated T cell populations increase in breast milk of HCMV-seropositive mothers during local HCMV reactivation.

Human cytomegalovirus (HCMV) can reactivate in the mammary gland during lactation and is shed into breast milk of nearly every HCMV-IgG-seropositive mother of a preterm infant. Dynamics of breast milk leukocytes during lactation, as well as blood leukocytes and the comparison between both in the context of HCMV reactivation is not well understood. Here, we present the BlooMil study that aimed at comparing changes of immune cells in blood and breast milk from HCMV-seropositive- vs -seronegative mothers, collected at four time ranges up to two months post-partum. Viral load was monitored by qPCR and nested PCR. Multiparameter flow cytometry was used to identify leukocyte subsets. CD3+ T cell frequencies were found to increase rapidly in HCMV-seropositive mothers' milk, while they remained unchanged in matched blood samples, and in both blood and breast milk of HCMV-seronegatives. The activation marker HLA-DR was more strongly expressed on CD4+ and CD8+ T cells in all breast milk samples than matched blood samples, but HCMV-seropositive mothers displayed a significant increase of HLA-DR+ CD4+ and HLA-DR+ CD8+ T cells during lactation. The CD4+/CD8+ T cell ratio was lower in breast milk of HCMV-seropositive mothers than in the blood. HCMV-specific CD8+ T cell frequencies (recognizing pp65 or IE1) were elevated in breast milk relative to blood, which might be due to clonal expansion of these cells during local HCMV reactivation. Breast milk contained very low frequencies of naïve T cells with no significant differences depending on serostatus. Taken together, we conclude that the distribution of breast milk leukocyte populations is different from blood leukocytes and may contribute to the decrease of breast milk viral load in the late phase of HCMV reactivation in the mammary gland.

Pharmacogenetic Markers of Favipiravir Safety in COVID-19 Treatment

The aim of the study was to evaluate the associations of different variants of AOX1 and CYP1A2 genes with safety parameters of favipiravir therapy in patients with COVID-19. Material and Methods. The study included 86 patients hospitalized at Moscow Clinical Hospital No. 15 with a COVID-19 diagnosis who received favipiravir as etiotropic therapy. Frequency of adverse reactions (bradycardia, dyspeptic disorders, increased transaminase levels) and various laboratory parameters (levels of ALT, AST, leukocytes) were compared between the carriers of «wild» and polymorphic variants of the genes studied after administration of the drug. The dynamics of these indicators before and after the therapy depending on the carriage of the variants of the genes studied were also compared. Results. There was no significant difference in the frequency of ad- verse reactions and laboratory parameters between the carriers of various variants of the studied genes. Haplotype analysis of the combination of different gene variants also did not reveal associations with therapy safety parameters. Upon the comparison of the parameters before and after treatment, an increase in the level of AST was noted in carriers of the AA genotype for both studied loci of the AOX1 gene (P=0.018 и P=0.009). At the same time, the level of AST increased in carriers of polymorphic variants of the CYP1A2*F1 gene (P=0.024). Leukocyte number increase was noted in carriers of polymorphic variants of AOX1 (rs10931910) (P=0.044), as well as «wild» genotypes AOX1 (rs55754655) (P=0.002) and CYP1A2*F1 (P=0.05). Conclusion. The associations of carriers of different AOX1 and CYP1A2 gene variants on the dynamics of AST and leukocytes in patients with COVID-19 after favipiravir therapy were revealed.

Sensitivity Analysis of a 2D Stochastic Agent-Based and PDE Diffusion Model for Cancer-on-Chip Experiments

The present work extends a previous paper where an agent-based and two-dimensional partial differential diffusion model was introduced for describing immune cell dynamics (leukocytes) in cancer-on-chip experiments. In the present work, new features are introduced for the dynamics of leukocytes and for their interactions with tumor cells, improving the adherence of the model to what is observed in laboratory experiments. Each system’s solution realization is a family of biased random walk trajectories, affected by the chemotactic gradients and in turn affecting them. A sensitivity analysis with respect to the model parameters is performed in order to assess the effect of their variation on both tumor cells and on leukocyte dynamics.

Actin dynamics regulation by TTC7A/PI4KIIIα limits DNA damage and cell death under confinement

The actin cytoskeleton has a crucial role in the maintenance of the immune homeostasis by controlling various cellular processes, including cell migration. Mutations in TTC7A have been described as the cause of a primary immunodeficiency associated to different degrees of gut involvement and alterations in the actin cytoskeleton dynamics. This study investigates the impact of TTC7A deficiency in immune homeostasis. In particular, the role of the TTC7A/phosphatidylinositol 4 kinase type III α pathway in the control of leukocyte migration and actin dynamics. Microfabricated devices were leveraged to study cell migration and actin dynamics of murine and patient-derived leukocytes under confinement at the single-cell level. We show that TTC7A-deficient lymphocytes exhibit an altered cell migration and reduced capacity to deform through narrow gaps. Mechanistically, TTC7A-deficient phenotype resulted from impaired phosphoinositide signaling, leading to the downregulation of the phosphoinositide 3-kinase/AKT/RHOA regulatory axis and imbalanced actin cytoskeleton dynamics. TTC7A-associated phenotype resulted in impaired cell motility, accumulation of DNA damage, and increased cell death in dense 3-dimensional gels in the presence of chemokines. These results highlight a novel role of TTC7A as a critical regulator of lymphocyte migration. Impairment of this cellular function is likely to contribute to the pathophysiology underlying progressive immunodeficiency in patients.

Behavioural immune landscapes of inflammation.

Transcriptional and proteomic profiling of individual cells have revolutionized interpretation of biological phenomena by providing cellular landscapes of healthy and diseased tissues1,2. These approaches, however, do not describe dynamic scenarios in which cells continuously change their biochemical properties and downstream 'behavioural' outputs3-5. Here we used 4D live imaging to record tens to hundreds of morpho-kinetic parameters describing the dynamics of individual leukocytes at sites of active inflammation. By analysing more than 100,000 reconstructions of cell shapes and tracks over time, we obtained behavioural descriptors of individual cells and used these high-dimensional datasets to build behavioural landscapes. These landscapes recognized leukocyte identities in the inflamed skin and trachea, and uncovered a continuum of neutrophil states inside blood vessels, including a large, sessile state that was embraced by the underlying endothelium and associated with pathogenic inflammation. Behavioural screening in 24 mouse mutants identified the kinase Fgr as a driver of this pathogenic state, and interference with Fgr protected mice from inflammatory injury. Thus, behavioural landscapes report distinct properties of dynamic environments at high cellular resolution.

Transendothelial migration induces differential migration dynamics of leukocytes in tissue matrix.

Leukocyte extravasation into inflamed tissue is a complex process that is difficult to capture as a whole in vitro. We employed a blood-vessel-on-a-chip model in which human endothelial cells were cultured in a tube-like lumen in a collagen-1 matrix. The vessels are leak tight, creating a barrier for molecules and leukocytes. Addition of inflammatory cytokine TNF-α (also known as TNF) caused vasoconstriction, actin remodelling and upregulation of ICAM-1. Introducing leukocytes into the vessels allowed real-time visualization of all different steps of the leukocyte transmigration cascade, including migration into the extracellular matrix. Individual cell tracking over time distinguished striking differences in migratory behaviour between T-cells and neutrophils. Neutrophils cross the endothelial layer more efficiently than T-cells, but, upon entering the matrix, neutrophils display high speed but low persistence, whereas T-cells migrate with low speed and rather linear migration. In conclusion, 3D imaging in real time of leukocyte extravasation in a vessel-on-a-chip enables detailed qualitative and quantitative analysis of different stages of the full leukocyte extravasation process in a single assay. This article has an associated First Person interview with the first authors of the paper.

First person – Bram van Steen and Lanette Kempers

ABSTRACT First Person is a series of interviews with the first authors of a selection of papers published in Journal of Cell Science, helping early-career researchers promote themselves alongside their papers. Bram van Steen and Lanette Kempers are co-first authors on ‘ Transendothelial migration induces differential migration dynamics of leukocytes in tissue matrix’, published in JCS. Bram is a PhD student in the laboratory of Jaap van Buul at Sanquin Research, Amsterdam, The Netherlands, investigating the secrets of cell behavior and migration using advanced models and microscopy. Lanette is a PhD student in the same lab studying the process of sprouting and angiogenesis using various microscopy approaches.

Dynamics of Macrophages and Polymorphonuclear Leukocytes Milk-Secreted by Buffaloes with Udders Characterized by Different Clinical Status.

The study evaluated the dynamics of macrophages and polymorphonuclear leukocytes milk-secreted by Mediterranean Buffaloes (MBs). Sixty quarter-milk-samples were collected and divided into three groups (n = 20 units each one): clinical mastitis (CM), subclinical mastitis (SCM), and intramammary infection (IMI). The control group consisted of an additional 20 healthy quarters. Their health status was assessed by clinical examination, quantitative somatic cell count (QSCC) and bacteriological milk culture. Finally, a differential somatic cell count (DSCC) was performed on all the milk samples. The mean percentage of macrophages, both in CM- and SCM-quarters, showed a significant difference as compared with the healthy-ones. Significant differences were also detected comparing the mean percentages of polymorphonuclear leukocytes between CM- and healthy-quarters, SCM and healthy, IMI and healthy. The QSCC revealed a weak-significant-negative-correlation with the quantitation of macrophages (r = −0.388), and a moderate-significant-positive-correlation with the polymorphonuclear leukocytes (r = 0.477). Macrophages and polymorphonuclear leukocytes showed a weak-significant-negative-correlation between them (r = −0.247). The interpretation of macrophages and polymorphonuclear leukocytes dynamics in milk provided beneficial information regarding the clinical status of the quarters enrolled. Future studies exploring the potential use of DSCC to improve udder health represent an interesting perspective in these ruminants.

Probing myeloid cell dynamics in ischaemic heart disease by nanotracer hot-spot imaging.

Ischaemic heart disease evokes a complex immune response. However, tools to track the systemic behaviour and dynamics of leukocytes non-invasively in vivo are lacking. Here, we present a multimodal hot-spot imaging approach using an innovative high-density lipoprotein-derived nanotracer with a perfluoro-crown ether payload (19F-HDL) to allow myeloid cell tracking by 19F magnetic resonance imaging. The 19F-HDL nanotracer can additionally be labelled with zirconium-89 and fluorophores to detect myeloid cells by in vivo positron emission tomography imaging and optical modalities, respectively. Using our nanotracer in atherosclerotic mice with myocardial infarction, we observed rapid myeloid cell egress from the spleen and bone marrow by in vivo 19F-HDL magnetic resonance imaging. Concurrently, using ex vivo techniques, we showed that circulating pro-inflammatory myeloid cells accumulated in atherosclerotic plaques and at the myocardial infarct site. Our multimodality imaging approach is a valuable addition to the immunology toolbox, enabling the study of complex myeloid cell behaviour dynamically.

HIV-1 Transcription Inhibitor 1E7-03 Restores LPS-Induced Alteration of Lung Leukocytes' Infiltration Dynamics and Resolves Inflammation in HIV Transgenic Mice.

Human immunodeficiency virus (HIV)-infected individuals treated with anti-retroviral therapy often develop chronic non-infectious lung disease. To determine the mechanism of HIV-1-associated lung disease we evaluated the dynamics of lung leukocytes in HIV-1 transgenic (Tg) mice with integrated HIV-1 provirus. In HIV-Tg mice, lipopolysacharide (LPS) induced significantly higher levels of neutrophil infiltration in the lungs compared to wild-type (WT) mice. In WT mice, the initial neutrophil infiltration was followed by macrophage infiltration and fast resolution of leukocytes infiltration. In HIV-Tg mice, resolution of lung infiltration by both neutrophils and macrophages was significantly delayed, with macrophages accumulating in the lumen of lung capillaries resulting in a 45% higher rate of mortality. Trans-endothelial migration of HIV-Tg macrophages was significantly reduced in vitro and this reduction correlated with lower HIV-1 gene expression. HIV-1 transcription inhibitor, 1E7-03, enhanced trans-endothelial migration of HIV-Tg macrophages in vitro, decreased lung neutrophil infiltration in vivo, and increased lung macrophage levels in HIV-Tg mice. Moreover, 1E7-03 reduced levels of inflammatory IL-6 cytokine, improved bleeding score and decreased lung injury. Together this indicates that inhibitors of HIV-1 transcription can correct abnormal dynamics of leukocyte infiltration in HIV-Tg, pointing to the utility of transcription inhibition in the treatment of HIV-1 associated chronic lung disease.

Correction of some indicators of blood of turkeys with cytomedines at different stages of growth and development

Correction of some indicators of blood of turkeys with cytomedines at different stages of growth and development

Temporal dynamics of peripheral neutrophil and lymphocytes following acute ischemic stroke.

The immune response to acute ischemic stroke (AIS) is implicated in diagnosis, prognosis, and intervention; however, the temporal dynamics of leukocytes following AIS are poorly understood. The purpose of this study was to characterize peripheral leukocyte dynamics following AIS among individuals with poor and favorable outcomes. A retrospective chart review was conducted among patients with a diagnosis of AIS who were treated at a comprehensive stroke center across a 3-year timeframe. Groups were defined according to stroke outcomes. Patients with poor outcomes were distinguished from those with favorable outcomes by discharge National Institute of Health Stroke Score, infarct size, and Modified Rankin Scale. Leukocyte counts were compared among controls and AIS outcome groups. The neutrophil-lymphocyte ratio (NLR) calculated at 48-72h post-AIS was identified as the strongest predictor of outcome. NLR was significantly higher in the poor outcome group (8.68 ± 0.93) compared with both the favorable outcome (4.5 ± 0.51, p = 0.009) and control group (4.33 ± 0.66, p < 0.001). Patients with a 48-72h NLR ≥ 4.58 were 5.58 times more likely to have a poor outcome than AIS patients with an NLR < 4.58. The results of this study improve the understanding of the immune response in AIS. Low neutrophil count relative to high lymphocyte count at 48-72h post-AIS should be considered a predictor of a favorable stroke outcome. Conversely, high neutrophil count relative to low lymphocyte count at 48-72h post-AIS should be considered a predictor of a poor stroke outcome.

Study of Bacillus methylotrophicus as a Probiotic Candidate Bacteria With Different Concentration Against Aeromonas hydrophila on Water as a Cultivation Media of Tilapia (Oreochromis niloticus)

Aeromonas hydrophila is still the major problem of the decline in tilapia production. The use of probiotics as disease prevention agents is one of alternative strategy. One of probiotic candidate that has been molecularly identified through 16s RNA was Bacillus methylotrophicus that was known as a bacteria that produces cyclic lipopeptides belonging to surfactin, iturin, and fengycin families. The aim of this research was to study B.methylotrophicus in inhibiting A.hydrophila in Oreochromis niloticus culture. This research consisted of in vitro and in vivo test that used experiment method with completely randomized design, 4 treatments (density of 1 fish/l) and 3 replications. The treatments were various mixture concentration of A.hydrophila at 102 CFU ml-1 with bacterial B.methylotrophicus (a) 0, (b) 107, (c) 108, (d) 109 CFU ml-1. Experimental animals used 120 fish at average weight of 13,8±1,6 g. Based on the in vitro test, B.methylotrophicus able to inhibit A.hydrophila categorized as bactericidal antibiotic and the most powerful concentration was 109 CFU ml-1 with clear zone of 24,9±4,2 mm. In vivo test did not significantly effect on survival rate, could slow down the growth of A. hydrophila, and had effect on dynamics of leukocytes, erythrocytes, hemoglobin, hematocrit value. Treatment D showed the highest survival rate (56.7%), followed by C (50,00%), B (43,33%), and A (30,00%). The value of leukocytes, erythrocytes, hemoglobin, hematocrit were 66.300–208.700 cells/mm3, 0,3–2,17x106 cells/mm3, 21,8-32,7%, 3,1-7,4 g/dl, respectively. The total bacteria viable count (TBC) in the water and A.hydrophila during treatment were 1,66x1011–1,25x1017 CFU ml-1 and 3,3x104– 1,7x107 CFU ml-1. This results showed that B.methylotrophicus could inhibit growth of A.hydrophila in in vitro, and able to increase the SR until 26, 7% in in vivo test.

Joint Modeling of Immune Reconstitution Post Haploidentical Stem Cell Transplantation in Pediatric Patients With Acute Leukemia Comparing CD34+-Selected to CD3/CD19-Depleted Grafts in a Retrospective Multicenter Study.

Rapid immune reconstitution (IR) following stem cell transplantation (SCT) is essential for a favorable outcome. The optimization of graft composition should not only enable a sufficient IR but also improve graft vs. leukemia/tumor effects, overcome infectious complications and, finally, improve patient survival. Especially in haploidentical SCT, the optimization of graft composition is controversial. Therefore, we analyzed the influence of graft manipulation on IR in 40 patients with acute leukemia in remission. We examined the cell recovery post haploidentical SCT in patients receiving a CD34+-selected or CD3/CD19-depleted graft, considering the applied conditioning regimen. We used joint model analysis for overall survival (OS) and analyzed the dynamics of age-adjusted leukocytes; lymphocytes; monocytes; CD3+, CD3+CD4+, and CD3+CD8+ T cells; natural killer (NK) cells; and B cells over the course of time after SCT. Lymphocytes, NK cells, and B cells expanded more rapidly after SCT with CD34+-selected grafts (P = 0.036, P = 0.002, and P < 0.001, respectively). Contrarily, CD3+CD4+ helper T cells recovered delayer in the CD34 selected group (P = 0.026). Furthermore, reduced intensity conditioning facilitated faster immune recovery of lymphocytes and T cells and their subsets (P < 0.001). However, the immune recovery for NK cells and B cells was comparable for patients who received reduced-intensity or full preparative regimens. Dynamics of all cell types had a significant influence on OS, which did not differ between patients receiving CD34+-selected and those receiving CD3/CD19-depleted grafts. In conclusion, cell reconstitution dynamics showed complex diversity with regard to the graft manufacturing procedure and conditioning regimen.

Programming and memory dynamics of innate leukocytes during tissue homeostasis and inflammation.

The field of innate immunity is witnessing a paradigm shift regarding "memory" and "programming" dynamics. Past studies of innate leukocytes characterized them as first responders to danger signals with no memory. However, recent findings suggest that innate leukocytes, such as monocytes and neutrophils, are capable of "memorizing" not only the chemical nature but also the history and dosages of external stimulants. As a consequence, innate leukocytes can be dynamically programmed or reprogrammed into complex inflammatory memory states. Key examples of innate leukocyte memory dynamics include the development of primed and tolerant monocytes when "programmed" with a variety of inflammatory stimulants at varying signal strengths. The development of innate leukocyte memory may have far-reaching translational implications, as programmed innate leukocytes may affect the pathogenesis of both acute and chronic inflammatory diseases. This review intends to critically discuss some of the recent studies that address this emerging concept and its implication in the pathogenesis of inflammatory diseases.

Ultrastructural Dynamics of Transendothelial Migration of Lymphocytes Through High Endothelial Venules (HEVs) of the Mucosa Associated Peyer’s Patches

Background and Purpose: Although the pivotal role of high endothelial venules (HEVs) in the migration of leukocytes from the blood into the secondary lymphoid parenchyma is well established, conflicting ideas concerning the cellular dynamics both of leukocytes and endothelial cells throughout the migratory processes have been present. Here we focused specifically on the cellular dynamics of HEVs from Peyer’s patches in an ultrastructural perspective. Materials and Methods: In order to determine the microstructural organization of transendothelial migration we used conventional methods for transmission electron microscopy. Results : Our results indicate that both lymphocytes and endothelial cells are highly active in the processes of transmigration steps, and a series of morphological and cellular alterations can occur depending upon their activity. Various types of cellular protrusions provide a direct contact between luminal lymphocytes and the endothelial cells at the initial phases of the migration. The endothelial protrusions subsequently embrace the lymphocytes and guide them into lymphoid stroma during the transcellular migration. Meanwhile, different sizes of vesicles show different cellular localizations according to their roles. The vesicles which are clustered near the lateral borders and the stand alone ones found only in the abluminal surfaces of endothelial cells might be involved in the paracellular migration. Concurrently, the other types of vesicles were smaller and appeared in the lateral border of the endothelial cells. Different from the clustered and abluminally localized vesicles, they were closely related with plasma membranes. Conclusions : These results indicated that not only adhesion molecules, but also cellular dynamics of leukocytes and endothelial cells regulate the leukocyte traffic into lymphoid stroma or vice versa.

Effects of nongenetic factors on immune cell dynamics in early childhood: The Generation R Study

Numbers of blood leukocyte subsets are highly dynamic in childhood and differ greatly between subjects. Interindividual variation is only partly accounted for by genetic factors. We sought to determine which nongenetic factors affect the dynamics of innate leukocytes and naive and memory lymphocyte subsets. We performed 6-color flow cytometry and linear mixed-effects modeling to define the dynamics of 62 leukocytesubsets from birth to 6years of age in 1182 children, with 1 to 5 measurements per subject. Subsequently, we defined the effect of prenatal maternal lifestyle-related or immune-mediated determinants, birth characteristics, and bacterial/viral exposure-related determinants on leukocyte subset dynamics. Functionally similar leukocyte populations were grouped by using unbiased hierarchical clustering of patterns of age-related leukocyte dynamics. Innate leukocyte numbers were high at birth and predominantly affected by maternal low education level. Naive lymphocyte counts peaked around 1year, whereas most memory lymphocyte subsets more gradually increased during the first 4years of life. Dynamics of CD4+ T cells were predominantly associated with sex, birth characteristics, and persistent infections with cytomegalovirus (CMV) or EBV. CD8+ T cells were predominantly associated with CMV and EBV infections, and T-cell receptor γδ+ T cells were predominantly associated with premature rupture of membranes and CMV infection. B-cell subsets were predominantly associated with sex, breast-feeding, and Helicobacter pylori carriership. Our study identifies specific dynamic patterns of leukocyte subset numbers, as well as nongenetic determinants that affect these patterns, thereby providing new insights into the shaping of the childhood immune system.

Post-translational modification-regulated leukocyte adhesion and migration.

Leukocytes undergo frequent phenotypic changes and rapidly infiltrate peripheral and lymphoid tissues in order to carry out immune responses. The recruitment of circulating leukocytes into inflamed tissues depends on integrin-mediated tethering and rolling of these cells on the vascular endothelium, followed by transmigration into the tissues. This dynamic process of migration requires the coordination of large numbers of cytosolic and transmembrane proteins whose functional activities are typically regulated by post-translational modifications (PTMs). Our recent studies have shown that the lysine methyltransferase, Ezh2, critically regulates integrin signalling and governs the adhesion dynamics of leukocytes via direct methylation of talin, a key molecule that controls these processes by linking integrins to the actin cytoskeleton. In this review, we will discuss the various modes of leukocyte migration and examine how PTMs of cytoskeletal/adhesion associated proteins play fundamental roles in the dynamic regulation of leukocyte migration. Furthermore, we will discuss molecular details of the adhesion dynamics controlled by Ezh2-mediated talin methylation and the potential implications of this novel regulatory mechanism for leukocyte migration, immune responses, and pathogenic processes, such as allergic contact dermatitis and tumorigenesis.

Removal of extracellular Toxoplasma gondii tachyzoites from suspended cell culture

Tachyzoites of Toxoplasma gondii, an obligate intracellular parasite, actively invade a broad spectrum of cell types. T. gondii infects leukocytes and spreads to distant organs such as the brain, lungs and muscles. However, the mechanism of T. gondii transmission from infected leukocytes to peripheral organs is unknown. To show the dynamics of infected leukocytes and intracellular parasites in vivo, previous studies have prepared T. gondii-infected leukocytes and injected them into circulation in experimental animals. However, when the infected leukocytes are prepared in vitro, some extracellular tachyzoites remain in the leukocyte cell culture because it is almost impossible to wash out these extracellular tachyzoites. These extracellular tachyzoites may distort experimental results. In this study, we report a method for removing extracellular tachyzoites from leukocyte culture suspension using antibody-conjugated magnetic beads. Using this method, extracellular tachyzoites in suspension cell culture can be effectively eliminated.