The beta2 integrin CD11c distinguishes a subset of cytotoxic pulmonary T cells with potent antiviral effects in vitro and in vivo

Background

The integrin CD11c is known as a marker for dendritic cells and has recently been described on T cells following lymphotropic choriomeningitis virus infection, a systemic infection affecting a multitude of organs. Here, we characterise CD11c bearing T cells in a murine model of localised pulmonary infection with respiratory syncytial virus (RSV).

Methods

Mice were infected intranasally with RSV and expression of β2 integrins and T lymphocyte activation markers were monitored by flow cytometry. On day 8 post RSV infection CD11c⁺ CD8⁺ and CD11c^- CD8⁺ T cells were assessed for cytokine production, cytotoxic activity and migration. Expression of CD11c mRNA in CD8⁺ T cells was assessed by quantitative PCR.

Results

Following RSV infection CD11c⁺ CD8⁺ T cells were detectable in the lung from day 4 onwards and accounted for 45.9 ± 4.8% of CD8⁺ T cells on day 8 post infection, while only few such cells were present in mediastinal lymph nodes, spleen and blood. While CD11c was virtually absent from CD8⁺ T cells in the absence of RSV infection, its mRNA was expressed in CD8⁺ T cells of both naïve and RSV infected mice. CD11c⁺, but not CD11c^-, CD8⁺ T cells showed signs of recent activation, including up-regulation of CD11a and expression of CD11b and CD69 and were recruited preferentially to the lung. In addition, CD11c⁺ CD8⁺ T cells were the major subset responsible for IFNγ production, induction of target cell apoptosis in vitro and reduction of viral titres in vivo.

Conclusion

CD11c is a useful marker for detection and isolation of pulmonary antiviral cytotoxic T cells following RSV infection. It identifies a subset of activated, virus-specific, cytotoxic T cells that exhibit potent antiviral effects in vivo.     

Compartments and their boundaries in vertebrate brain development

Fifteen years ago, cell lineage restriction boundaries were discovered in the embryonic vertebrate hindbrain, subdividing it into a series of cell-tight compartments (known as rhombomeres). Compartition, together with segmentally reiterative neuronal architecture and the nested expression of Hox genes, indicates that the hindbrain has a truly metameric organization. This finding initiated a search for compartments in other regions of the developing brain. The results of recent studies have clarified where compartment boundaries exist, have shed light on molecular mechanisms that underlie their formation and have revealed an important function of these boundaries: the positioning and stabilization of local signalling centres.     

Wnt6 marks sites of epithelial transformations in the chick embryo

In a screen for Wnt genes executing the patterning function of the vertebrate surface ectoderm, we have isolated a novel chick Wnt gene, chick Wnt6. This gene encodes the first pan-epidermal Wnt signalling molecule. Further sites of expression are the boundary of the early neural plate and surface ectoderm, the roof of mesencephalon, pretectum and dorsal thalamus, the differentiating heart, and the otic vesicle. The precise sites of Wnt6 expression coincide with crucial changes in tissue architecture, namely epithelial remodelling and epithelial-mesenchymal transformation (EMT). Moreover, the expression of Wnt6 is closely associated with areas of Bmp signalling.     

The migration of cerebellar rhombic lip derivatives

We have used cell labelling, co-culture and time-lapse confocal microscopy to investigate tangential neuronal migration from the rhombic lip. Cerebellar rhombic lip derivatives demonstrate a temporal organisation with respect to their morphology and response to migration cues. Early born cells, which migrate into ventral rhombomere 1, have a single long leading process that turns at the midline and becomes an axon. Later born granule cell precursors also migrate ventrally but halt at the lateral edge of the cerebellum, correlating with a loss of sensitivity to netrin 1 and expression of Robo2. The rhombic lip and ventral midline express Slit2 and both early and late migrants are repelled by sources of Slit2 in co-culture. These studies reveal an intimate relationship between birthdate, response to migration cues and neuronal fate in an identified population of migratory cells. The use of axons in navigating cell movement suggests that tangential migration is an elaboration of the normal process of axon extension.     

Evidence of functional redundancy between MID proteins: implications for the presentation of Opitz syndrome

Opitz G/BBB syndrome (OS) is a congenital defect characterized by hypertelorism and hypospadias, but additional midline malformations are also common in OS patients. X-linked OS is caused by mutations in the ubiquitin ligase MID1. In chick, MID1 is involved in left-right determination: a mutually repressive relationship between Shh and cMid1 in Hensen's node plays a key role in establishing the avian left-right axis. We have utilized our existing knowledge of the molecular basis of avian L/R determination to investigate the possible existence of functional redundancy between MID1 and its close homologue MID2. The expression of cMid2 overlaps with that of cMid1 in the node, and we demonstrate that MID2 can both mimic MID1 function as a right side determinant and rescue the laterality defects caused by knocking down endogenous MID proteins in the node. Our results show that MID2 is able to compensate for an absence in MID1 during chick left-right determination and may explain why OS patients do not suffer laterality defects despite the association between midline and L/R development. The demonstration of functional redundancy between MID1 and MID2 in the node provides supports for the hypothesis that partial functional redundancy between MID proteins in other developing structures contributes to the wide variability of OS phenotype.     

The PINE study: rationale and design of a randomised comparison of epidural injection of local anaesthetics and steroids versus care-as-usual to prevent postherpetic neuralgia in the elderly [ISRCTN32866390]

BACKGROUND: Postherpetic neuralgia (PHN) is by far the most common complication of herpes zoster (HZ) and one of the most intractable pain disorders. Since PHN is seen most often in the elderly, the number of patients with this disorder is expected to increase in our ageing society. PHN may last for months to years and has a high impact on the quality of life. The results of PHN treatment are rather disappointing. Epidural injection of local anaesthetics and steroids in the acute phase of HZ is a promising therapy for the prevention of PHN. Since randomised trials on the effectiveness of this intervention are lacking, the PINE (Prevention by epidural Injection of postherpetic Neuralgia in the Elderly) study was set up. The PINE study compares the effectiveness and cost-effectiveness of a single epidural injection of local anaesthetics and steroids during the acute phase of HZ with that of care-as-usual (i.e. antivirals and analgesics) in preventing PHN in elderly patients. METHODS / DESIGN: The PINE study is an open, multicenter clinical trial in which 550 elderly (age >/= 50 yr.) patients who consult their general practitioner in the acute phase of HZ (rash < 7 days) are randomised to one of the treatment groups. The primary clinical endpoint is the presence of HZ-related pain one month after the onset of the rash. Secondary endpoints include duration and severity of pain, re-interventions aiming to treat the existing pain, side effects, quality of life, and cost-effectiveness. CONCLUSION: The PINE study is aimed to quantify the (cost-) effectiveness of a single epidural injection during the acute phase of HZ on the prevention of PHN.     

Spectral correspondence between visual spectral sensitivity and bioluminescence emission spectra in the click beetle Pyrophorus punctatissimus (Coleoptera: Elateridae)

The presence of two spectral mechanisms, near-ultraviolet and green (lambda(max)=545nm), is strongly suggested by electroretinographic visual spectral sensitivity curves obtained under dark and red chromatic adaptation conditions in the compound eyes of the click beetle Pyrophorus punctatissimus. The bioluminescence emission of the dorsal prothoracic lanterns is deep green (lambda(max)=543nm) and that of the ventral abdominal lantern is lime green (lambda(max)=556nm) in colour in P. punctatissimus. A broad green visual receptor would detect both deep green and lime green bioluminescent optical signals.     

Highly prolific Booroola sheep have a mutation in the intracellular kinase domain of bone morphogenetic protein IB receptor (ALK-6) that is expressed in both oocytes and granulosa cells

The Booroola fecundity gene (FecB) increases ovulation rate and litter size in sheep and is inherited as a single autosomal locus. The effect of FecB is additive for ovulation rate (increasing by about 1.6 corpora lutea per cycle for each copy) and has been mapped to sheep chromosome 6q23-31, which is syntenic to human chromosome 4q21-25. Bone morphogenetic protein IB (BMP-IB) receptor (also known as ALK-6), which binds members of the transforming growth factor-beta (TGF-beta) superfamily, is located in the region containing the FecB locus. Booroola sheep have a mutation (Q249R) in the highly conserved intracellular kinase signaling domain of the BMP-IB receptor. The mutation segregated with the FecB phenotype in the Booroola backcross and half-sib flocks of sheep with no recombinants. The mutation was not found in individuals from a number of sheep breeds not derived from the Booroola strain. BMPR-IB was expressed in the ovary and in situ hybridization revealed its specific location to the oocyte and the granulosa cell. Expression of mRNA encoding the BMP type II receptor was widespread throughout the ovary. The mutation in BMPR-IB found in Booroola sheep is the second reported defect in a gene from the TGF-beta pathway affecting fertility in sheep following the recent discovery of mutations in the growth factor, GDF9b/BMP15.