Effector CD4 T cells recognize intravascular antigen presented by patrolling monocytes.

Although effector CD4 T cells readily respond to antigen outside the vasculature, how they respond to intravascular antigens is unknown. Here we show the process of intravascular antigen recognition using intravital multiphoton microscopy of glomeruli. CD4 T cells undergo intravascular migration within uninflamed glomeruli.

In Vivo Imaging of Inflamed Glomeruli Reveals Dynamics of Neutrophil Extracellular Trap Formation in Glomerular Capillaries.

Neutrophil extracellular traps (NETs) have been documented in glomeruli of patients with glomerulonephritis. However, the dynamics of NET formation in the glomerulus and their functional contribution to acute glomerular injury are poorly understood. Herein, we used in vivo multiphoton microscopy to investigate NET formation in the acutely inflamed glomerulus.

Patrolling monocytes promote intravascular neutrophil activation and glomerular injury in the acutely inflamed glomerulus.

Nonclassical monocytes undergo intravascular patrolling in blood vessels, positioning them ideally to coordinate responses to inflammatory stimuli. Under some circumstances, the actions of monocytes have been shown to involve promotion of neutrophil recruitment. However, the mechanisms whereby patrolling monocytes control the actions of neutrophils in the circulation are unclear.

Genetic polymorphisms in the CD14 gene are associated with monocyte activation and carotid intima-media thickness in HIV-infected patients on antiretroviral therapy.

HIV-infected individuals on antiretroviral therapy (ART) are at increased risk of cardiovascular disease (CVD). Given the relationship between innate immune activation and CVD, we investigated the association of single-nucleotide polymorphisms (SNPs) in TLR4 and CD14 and carotid intima-media thickness (cIMT), a surrogate measurement for CVD, in HIV-infected individuals on ART and HIV-uninfected controls as a cross-sectional, case-control study. We quantified the frequency of monocyte subsets (CD14, CD16), markers of monocyte activation (CD38, HLA-DR), and endothelial adhesion (CCR2, CX3CR1, CD11b) by flow cytometry.

C-reactive protein as a predictor of cardiovascular risk in HIV-infected individuals.

Unlabelled: Background In some studies HIV infection confers approximately two-fold higher risk of cardiac events compared with the general population. C-reactive protein (CRP) is a well-characterised biomarker of cardiac events in the general population and is also elevated in patients with HIV infection. The aim of this study was to determine the predictive value of CRP for cardiac events in HIV-infected individuals.

Regulatory T cells dynamically regulate selectin ligand function during multiple challenge contact hypersensitivity.

Regulatory T cells (Tregs) play critical roles in restricting T cell-mediated inflammation. In the skin, this is dependent on expression of selectin ligands required for leukocyte rolling in dermal microvessels. However, whether there are differences in the molecules used by Tregs and proinflammatory T cells to undergo rolling in the skin remains unclear.

Associations between surface markers on blood monocytes and carotid atherosclerosis in HIV-positive individuals.

Chronic HIV infection is associated with increased risk of cardiovascular disease (CVD), including in patients with virological suppression. Persistent innate immune activation may contribute to the development of CVD via activation of monocytes in these patients. We investigated whether changes in monocyte phenotype predict subclinical atherosclerosis in virologically suppressed HIV-positive individuals with low cardiovascular risk.

Imaging inflammatory leukocyte recruitment in kidney, lung and liver--challenges to the multi-step paradigm.

Intravital microscopy has been essential in establishing the multi-step paradigm that describes how leukocytes in the bloodstream interact with the blood vessel wall during the process of leukocyte recruitment. Much of this work has been performed in readily-visualized tissues such as the mesentery and the cremaster muscle, where leukocyte-endothelial cell interactions are restricted to postcapillary venules. However, the microvasculatures of the liver, lung and renal glomerulus differ markedly from these conventionally structured microvascular beds.

Multiphoton imaging reveals a new leukocyte recruitment paradigm in the glomerulus.

In contrast with many capillary beds, the glomerulus readily supports leukocyte recruitment. However, little is known regarding the actions of leukocytes following their recruitment to glomeruli. We used multiphoton confocal microscopy to examine leukocyte behavior in the glomerular microvasculature.

Endothelial cell activation promotes foam cell formation by monocytes following transendothelial migration in an in vitro model.

Foam cells are a pathological feature present at all stages of atherosclerosis. Foam cells develop from monocytes that enter the nascent atheroma and subsequently ingest modified low density lipoproteins (LDL). The regulation of this process has previously been studied in vitro using cultured macrophage fed modified LDL.

The macrophage: the intersection between HIV infection and atherosclerosis.

HIV-infected individuals are at increased risk of coronary artery disease (CAD) with underlying mechanisms including chronic immune activation and inflammation secondary to HIV-induced microbial translocation and low-grade endotoxemia; direct effects of HIV and viral proteins on macrophage cholesterol metabolism; and dyslipidemia related to HIV infection and specific antiretroviral therapies. Monocytes are the precursors of the lipid-laden foam cells within the atherosclerotic plaque and produce high levels of proinflammatory cytokines such as IL-6. The minor CD14+/CD16+ "proinflammatory" monocyte subpopulation is preferentially susceptible to HIV infection and may play a critical role in the pathogenesis of HIV-related CAD.

Effects of HIV-1 infection in vitro on transendothelial migration by monocytes and monocyte-derived macrophages.

Monocytes constitutively migrate from the bloodstream across the vascular endothelium for systemic immune surveillance and maintenance of macrophage populations. They also perform reverse transendothelial migration (TEM) across the endothelium, which is required for entry of tissue monocytes/macrophages into the lymphatics or back into the bloodstream. We have modeled these processes previously using HUVEC monolayers grown on three-dimensional collagen matrices.