Regulation and function of T1/ST2 expression on CD4+ T cells: induction of type 2 cytokine production by T1/ST2 cross-linking

The orphan receptor T1/ST2, a member of the IL-1R family, is preferentially expressed on the surface of murine Th2 cells. In this study, we analyzed the kinetics and function of T1/ST2 expression on Th2 cells in vitro. Whereas naive CD4(+) cells did not express T1/ST2, most CD4(+) cells became T1/ST2(+) upon repeated antigenic stimulation under Th2-polarizing conditions. Flow cytometric analyses revealed that the kinetics of T1/ST2 expression on Th2 cells was delayed compared with the kinetics of type 2 cytokine production. Exogenous IL-6, IL-5, IL-1, and TNF-alpha enhanced the expression of T1/ST2 on Th2 cells, and IL-6 was by far most effective in this regard. However, the expression of T1/ST2 did not depend on the presence of IL-6 and was also detected in IL-6-deficient mice. Most important, cross-linking of T1/ST2 provided a costimulatory signal for Th2 but not Th1 cells and directly induced proliferation and type 2 cytokine production. Thus, T1/ST2 is not only a Th2 cell marker but also plays an important role in the activation of Th2 cells.     

Influence of Granulocyte-Macrophage Colony-Stimulating Factor or Influenza Vaccination on HLA-DR,Infection and Delirium Days in Immunosuppressed Surgical Patients: Double Blind,Randomised Controlled Trial

Purpose

Surgical patients are at high risk for developing infectious complications and postoperative delirium. Prolonged infections and delirium result in worse outcome. Granulocyte-macrophage colony-stimulating factor (GM-CSF) and influenza vaccination are known to increase HLA-DR on monocytes and improve immune reactivity. This study aimed to investigate whether GM-CSF or vaccination reverses monocyte deactivation. Secondary aims were whether it decreases infection and delirium days after esophageal or pancreatic resection over time.

Methods

In this prospective, randomized, placebo-controlled, double-blind, double dummy trial setting on an interdisciplinary ICU of a university hospital 61 patients with immunosuppression (monocytic HLA-DR [mHLA-DR] <10,000 monoclonal antibodies [mAb] per cell) on the first day after esophageal or pancreatic resection were treated with either GM-CSF (250 μg/m²/d), influenza vaccination (Mutagrip 0.5 ml/d) or placebo for a maximum of 3 consecutive days if mHLA-DR remained below 10,000 mAb per cell. HLA-DR on monocytes was measured daily until day 5 after surgery. Infections and delirium were followed up for 9 days after surgery. Primary outcome was HLA-DR on monocytes, and secondary outcomes were duration of infection and delirium.

Results

mHLA-DR was significantly increased compared to placebo (p < 0.001) and influenza vaccination (p < 0.001) on the second postoperative day. Compared with placebo, GM-CSF-treated patients revealed shorter duration of infection (p < 0.001); the duration of delirium was increased after vaccination (p = 0.003).

Conclusion

Treatment with GM-CSF in patients with postoperative immune suppression was safe and effective in restoring monocytic immune competence. Furthermore, therapy with GM-CSF reduced duration of infection in immune compromised patients. However, influenza vaccination increased duration of delirium after major surgery.

Trial Registration

www.controlled-trials.com ISRCTN27114642     

Shedding light on host niches: label‐free in situ detection of Mycobacterium gordonae via carotenoids in macrophages by Raman microspectroscopy

Macrophages are the primary habitat of pathogenic mycobacteria during infections. Current research about the host–pathogen interaction on the cellular level is still going on. The present study proves the potential of Raman microspectroscopy as a label‐free and non‐invasive method to investigate intracellular mycobacteria in situ. Therefore, macrophages were infected with Mycobacterium gordonae, a mycobacterium known to cause inflammation linked to intracellular survival in macrophages. Here, we show that Raman maps provided spatial and spectral information about the position of bacteria within determined cell margins of macrophages in two‐dimensional scans and in three‐dimensional image stacks. Simultaneously, the relative intracellular concentration and distributions of cellular constituents such as DNA, proteins and lipids provided phenotypic information about the infected macrophages. Locations of bacteria outside or close to the outer membrane of the macrophages were notably different in their spectral pattern compared with intracellular once. Furthermore, accumulations of bacteria inside of macrophages exhibit distinct spectral/molecular information because of the chemical composition of the intracellular microenvironment. The data show that the connection of microscopically and chemically gained information provided by Raman microspectroscopy offers a new analytical way to detect and to characterize the mycobacterial infection of macrophages.     

A novel mode of chromosomal evolution peculiar to filamentous Ascomycete fungi

Background  

Gene loss, inversions, translocations, and other chromosomal rearrangements vary among species, resulting in different rates of structural genome evolution. Major chromosomal rearrangements are rare in most eukaryotes, giving large regions with the same genes in the same order and orientation across species. These regions of macrosynteny have been very useful for locating homologous genes in different species and to guide the assembly of genome sequences. Previous analyses in the fungi have indicated that macrosynteny is rare; instead, comparisons across species show no synteny or only microsyntenic regions encompassing usually five or fewer genes. To test the hypothesis that chromosomal evolution is different in the fungi compared to other eukaryotes, synteny was compared between species of the major fungal taxa.     

Stability analysis of the elbow with a load

We present a model of the human elbow and study the problem of existence and stability of equilibrium states. Our main goal is to demonstrate that stable equilibrium states exist just on grounds of the mechanical properties of the muscles and the skeleton. In particular, additional control mechanisms such as reflexes are not necessary to obtain stability. We assume that the activation of flexor and extensor muscles is constant and such that the right angle is an equilibrium state. We give a complete bifurcation diagram of all equilibrium states in terms of the elbow angle, the activation of the muscles and the mass of a load. Moreover, we define a dimensionless model parameter which allows to determine whether or not there are stable equilibria at an angle of ninety degrees. It turns out that the dependency of the muscle forces on the length of the muscles is the crucial factor for the stability of such an equilibrium.     

Using the realized relationship matrix to disentangle confounding factors for the estimation of genetic variance components of complex traits

Background

In the analysis of complex traits, genetic effects can be confounded with non-genetic effects, especially when using full-sib families. Dominance and epistatic effects are typically confounded with additive genetic and non-genetic effects. This confounding may cause the estimated genetic variance components to be inaccurate and biased.

Methods

In this study, we constructed genetic covariance structures from whole-genome marker data, and thus used realized relationship matrices to estimate variance components in a heterogenous population of ~ 2200 mice for which four complex traits were investigated. These mice were genotyped for more than 10,000 single nucleotide polymorphisms (SNP) and the variances due to family, cage and genetic effects were estimated by models based on pedigree information only, aggregate SNP information, and model selection for specific SNP effects.

Results and conclusions

We show that the use of genome-wide SNP information can disentangle confounding factors to estimate genetic variances by separating genetic and non-genetic effects. The estimated variance components using realized relationship were more accurate and less biased, compared to those based on pedigree information only. Models that allow the selection of individual SNP in addition to fitting a relationship matrix are more efficient for traits with a significant dominance variance.