Antigen recognition reinforces regulatory T cell mediated Leishmania major persistence.

Cutaneous Leishmania major infection elicits a rapid T cell response that is insufficient to clear residually infected cells, possibly due to the accumulation of regulatory T cells in healed skin. Here, we used Leishmania-specific TCR transgenic mice as a sensitive tool to characterize parasite-specific effector and immunosuppressive responses in vivo using two-photon microscopy. We show that Leishmania-specific Tregs displayed higher suppressive activity compared to polyclonal Tregs, that was mediated through IL-10 and not through disrupting cell-cell contacts or antigen presentation.

Longitudinal Assessment of SARS-CoV-2-Specific T Cell Cytokine-Producing Responses for 1 Year Reveals Persistence of Multicytokine Proliferative Responses, with Greater Immunity Associated with Disease Severity.

Cell-mediated immunity is critical for long-term protection against most viral infections, including coronaviruses. We studied 23 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected survivors over a 1-year post-symptom onset (PSO) interval by cytokine enzyme-linked immunosorbent spot assay (ELISpot) assay. All subjects demonstrated SARS-CoV-2-specific gamma interferon (IFN-γ), interleukin 2 (IL-2), and granzyme B (GzmB) T cell responses at presentation, with greater frequencies in severe disease.

T cell migration potentiates HIV infection by enhancing viral fusion and integration.

T cells actively migrate along reticular networks within lymphoid organs in search for cognate antigen, but how these behaviors impact HIV entry and infection is unclear. Here, we show that migratory T cells in 3D collagen matrix display significantly enhanced infection and integration by cell-free R5-tropic lab adapted and transmitted/founder molecular HIV clones in the absence of exogenous cytokines or cationic polymers. Using two different collagen matrices that either support or restrict T cell migration, we observe high levels of HIV fusion in migratory T cells, whereas non-motile T cells display low viral entry and integration.

Connectomes across development reveal principles of brain maturation.

An animal's nervous system changes as its body grows from birth to adulthood and its behaviours mature. The form and extent of circuit remodelling across the connectome is unknown. Here we used serial-section electron microscopy to reconstruct the full brain of eight isogenic Caenorhabditis elegans individuals across postnatal stages to investigate how it changes with age.

External Beam Radiation Therapy in pT4 Well-Differentiated Thyroid Cancer: A Population-Based Study of 405 Patients.

Purpose: The benefit of external beam radiation therapy (EBRT) in locally advanced, well- differentiated thyroid cancer (WDTC) is uncertain. The purpose of this study is to evaluate locoregional recurrence (LRR), progression-free survival, and cause-specific survival (CSS) of patients with pT4 well-differentiated thyroid carcinoma.

Methods And Materials: A population-based retrospective review was conducted of consecutive patients with pT4 WDTC (per the American Joint Committee on Cancer, 8th edition, criteria) treated provincially between 1985 and 2013.

Cancellation of elective surgery: rates, reasons and effect on patient satisfaction.

Background: The cancellation of elective surgeries is a major problem that increases wait times, exacerbates costs and can negatively affect patients, both psychologically and physically. Our objectives were to investigate the reasons for cancellations across specialties at a single centre, to compare these reasons with previous data from the same centre between 2005 and 2009 and to examine how cancellations affected patients' lives and views of the medical system in cases when the cancellations were potentially preventable.

Methods: Cancellation records of all elective surgeries scheduled between June 1, 2012, and Jan.

Performance on sit-to-stand tests in relation to measures of functional fitness and sarcopenia diagnosis in community-dwelling older adults.

Background: The sit-to-stand (STS) test has been deployed as surrogate measures of strength or physical performance in sarcopenia diagnosis. This study examines the relationship of two common STS variants - Five Times Sit-to-Stand Test (5TSTS) and 30 s Chair Stand Test (30CST) - with grip strength, muscle mass and functional measures, and their impact on sarcopenia prevalence in community-dwelling older adults.

Methods: This is a cross-sectional analysis of 887 community-dwelling adults aged ≥50 years.

Visualizing Cellular Dynamics and Protein Localization in 3D Collagen.

Immune cells migrate and communicate through cell-to-cell interactions and cytokines to coordinate the specificity and timing of the immune response. While studying these events in cell culture are standard procedure, spatiotemporal dynamics of cell-to-cell interactions within three-dimensional (3D) environments are critical in generating appropriate effector functions. Here, we present a detailed protocol to study cells within an all-in-one 3D collagen matrix that is amenable to live-cell microscopy and immunohistochemistry.

Systematic Examination of Antigen-Specific Recall T Cell Responses to SARS-CoV-2 versus Influenza Virus Reveals a Distinct Inflammatory Profile.

There is a pressing need for an in-depth understanding of immunity to SARS-CoV-2. In this study, we investigated human T cell recall responses to fully glycosylated spike trimer, recombinant N protein, as well as to S, N, M, and E peptide pools in the early convalescent phase and compared them with influenza-specific memory responses from the same donors. All subjects showed SARS-CoV-2-specific T cell responses to at least one Ag.

HIV-Captured DCs Regulate T Cell Migration and Cell-Cell Contact Dynamics to Enhance Viral Spread.

Trafficking of cell-associated HIV-1 from the genital mucosa to lymphoid organs represents a critical first step toward systemic infection. Mature DCs capture and transmit HIV-1 to T cells, but insights into DC-to-T cell viral spread dynamics within a 3-dimensional environment is lacking. Using live-cell imaging, we show that mature DCs rapidly compartmentalize HIV-1 within surface-accessible invaginations near the uropod.

HIV Infection Stabilizes Macrophage-T Cell Interactions To Promote Cell-Cell HIV Spread.

Macrophages are susceptible to HIV infection and play an important role in viral dissemination through cell-cell contacts with T cells. However, our current understanding of macrophage-to-T cell HIV transmission is derived from studies that do not consider the robust migration and cell-cell interaction dynamics between these cells. Here, we performed live-cell imaging studies in 3-dimensional (3D) collagen that allowed CD4 T cells to migrate and to locate and engage HIV-infected macrophages, modeling the dynamic aspects of the environment in which these contacts frequently occur.

HIV-1 Balances the Fitness Costs and Benefits of Disrupting the Host Cell Actin Cytoskeleton Early after Mucosal Transmission.

HIV-1 primarily infects T lymphocytes and uses these motile cells as migratory vehicles for effective dissemination in the host. Paradoxically, the virus at the same time disrupts multiple cellular processes underlying lymphocyte motility, seemingly counterproductive to rapid systemic infection. Here we show by intravital microscopy in humanized mice that perturbation of the actin cytoskeleton via the lentiviral protein Nef, and not changes to chemokine receptor expression or function, is the dominant cause of dysregulated infected T cell motility in lymphoid tissue by preventing stable cellular polarization required for fast migration.

Public attitudes towards mobile health in Singapore: a cross-sectional study.

Background: Smartphone-mediated mobile health (mHealth) may assist patients with medication adherence, and disease monitoring. This study aimed to describe awareness and usage of, and attitudes towards, mHealth among the public in Singapore who own a smartphone. It also aimed to identify factors that influenced the above in the study population.

Leukocyte Tracking Database, a collection of immune cell tracks from intravital 2-photon microscopy videos.

Recent advances in intravital video microscopy have allowed the visualization of leukocyte behavior in vivo, revealing unprecedented spatiotemporal dynamics of immune cell interaction. However, state-of-the-art software and methods for automatically measuring cell migration exhibit limitations in tracking the position of leukocytes over time. Challenges arise both from the complex migration patterns of these cells and from the experimental artifacts introduced during image acquisition.

Imaging features of renal complications after crizotinib treatment for non-small-cell lung cancer: a case report.

Crizotinib has been approved for the treatment of advanced ALK-positive non-small cell lung cancer. Its use is associated with the development of complex renal cysts. However, there is limited literature regarding imaging features of renal cystic disease during crizotinib therapy and its complications or progression.

Life without a Host Cell: What is Cryptosporidium?

Cryptosporidium is a parasite responsible for widespread disease in livestock and humans. Recent phylogenetic reclassification of Cryptosporidium from a coccidian to a gregarine dictates an urgent need to reconsider the biology and behavior of this parasite. Overwhelming data now confirm that, like its close relatives, Cryptosporidium is a facultatively epicellular apicomplexan that is able to multiply in a host cell-free environment.

Extracellular excystation and development of Cryptosporidium: tracing the fate of oocysts within Pseudomonas aquatic biofilm systems.

Background: Aquatic biofilms often serve as environmental reservoirs for microorganisms and provide them with a nutrient-rich growth environment under harsh conditions. With regard to Cryptosporidium, biofilms can serve as environmental reservoirs for oocysts, but may also support the growth of additional Cryptosporidium stages.

Results: Here we used confocal laser scanning microscopy, scanning electron microscopy (SEM), and flow cytometry to identify and describe various Cryptosporidium developmental stages present within aquatic biofilm systems, and to directly compare these to stages produced in cell culture.

Multiplication of the waterborne pathogen Cryptosporidium parvum in an aquatic biofilm system.

Background: In natural aquatic environments biofilms are known to act as environmental reservoirs for Cryptosporidium parvum oocysts. However, the fate of these oocysts within biofilms has yet to be determined.

Methods: This study aimed to identify if biofilms have the ability to support the multiplication of Cryptosporidium by measuring the change in parasite number over time using quantitative polymerase chain reaction (qPCR) and detecting the possible extracellular developmental stages using a combination of confocal microscopy and immunolabelling techniques.

Giardia duodenalis assemblage-specific induction of apoptosis and tight junction disruption in human intestinal epithelial cells: effects of mixed infections.

In view of the interest in genotype-specific pathogenesis in Giardia duodenalis , the aim of the present study was to examine the effects of infection with different, or mixed, G. duodenalis assemblages on the integrity of human intestinal epithelia. To that end, human epithelial cells (HCT-8) were cultured and exposed to different G.

Labeling surface epitopes to identify Cryptosporidium life stages using a scanning electron microscopy-based immunogold approach.

The Apicomplexan parasite Cryptosporidium parvum is responsible for the widespread disease cryptosporidiosis, in both humans and livestock. The nature of C. parvum infection is far from understood and many questions remain in regard to host-parasite interactions, limiting successful treatment of the disease.

Spinal abscess: a case series.

Objective: Spinal abscess is a rare but potentially devastating condition. We present a case series, looking into its presentation, risk factors, management and outcome.

Methods: Five patients over a 10 year period were identified, with a discharge diagnosis code of 'spinal abscess, 324.

Imaging surveillance of the breast in a patient diagnosed with scleroderma after breast-conserving surgery and radiotherapy.

Collagen vascular disease (CVD), particularly scleroderma, is a contraindication to radiation therapy because of increased risk of fibrosis. We report a patient with early stage breast cancer diagnosed with scleroderma after breast-conserving surgery and radiation. She developed marked breast fibrosis, rendering mammographic, sonographic, and clinical surveillance ineffective.