Guidelines for the use of flow cytometry and cell sorting in immunological studies (second edition)

These guidelines are a consensus work of a considerable number of members of the immunology and flow cytometry community. They provide the theory and key practical aspects of flow cytometry enabling immunologists to avoid the common errors that often undermine immunological data. Notably, there are comprehensive sections of all major immune cell types with helpful Tables detailing phenotypes in murine and human cells. The latest flow cytometry techniques and applications are also described, featuring examples of the data that can be generated and, importantly, how the data can be analysed. Furthermore, there are sections detailing tips, tricks and pitfalls to avoid, all written and peer-reviewed by leading experts in the field, making this an essential research companion.

Interleukin (IL)-22, a novel human cytokine that signals through the interferon receptor-related proteins CRF2-4 and IL-22R

We report the identification of a novel human cytokine, distantly related to interleukin (IL)-10, which we term IL-22. IL-22 is produced by activated T cells. IL-22 is a ligand for CRF2-4, a member of the class II cytokine receptor family. No high affinity ligand has yet been reported for this receptor, although it has been reported to serve as a second component in IL-10 signaling. A new member of the interferon receptor family, which we term IL-22R, functions as a second component together with CRF2-4 to enable IL-22 signaling. IL-22 does not bind the IL-10R. Cell lines were identified that respond to IL-22 by activation of STATs 1, 3, and 5, but were unresponsive to IL-10. In contrast to IL-10, IL-22 does not inhibit the production of proinflammatory cytokines by monocytes in response to LPS nor does it impact IL-10 function on monocytes, but it has modest inhibitory effects on IL-4 production from Th2 T cells.

Identification of an angiogenic mitogen selective for endocrine gland endothelium

The known endothelial mitogens stimulate growth of vascular endothelial cells without regard to their tissue of origin. Here we report a growth factor that is expressed largely in one type of tissue and acts selectively on one type of endothelium. This molecule, called endocrine-gland-derived vascular endothelial growth factor (EG-VEGF), induced proliferation, migration and fenestration (the formation of membrane discontinuities) in capillary endothelial cells derived from endocrine glands. However, EG-VEGF had little or no effect on a variety of other endothelial and non-endothelial cell types tested. Similar to VEGF, EG-VEGF possesses a HIF-1 binding site, and its expression is induced by hypoxia. Both EG-VEGF and VEGF resulted in extensive angiogenesis and cyst formation when delivered in the ovary. However, unlike VEGF, EG-VEGF failed to promote angiogenesis in the cornea or skeletal muscle. Expression of human EG-VEGF messenger RNA is restricted to the steroidogenic glands, ovary, testis, adrenal and placenta and is often complementary to the expression of VEGF, suggesting that these molecules function in a coordinated manner. EG-VEGF is an example of a class of highly specific mitogens that act to regulate proliferation and differentiation of the vascular endothelium in a tissue-specific manner.

A dendritic-cell-derived C-C chemokine that preferentially attracts naive T cells

Dendritic cells form a system of highly efficient antigen-presenting cells. After capturing antigen in the periphery, they migrate to lymphoid organs where they present the antigen to T cells. Their seemingly unique ability to interact with and sensitize naive T cells gives dendritic cells a central role in the initiation of immune responses and allows them to be used in therapeutic strategies against cancer, viral infection and other diseases. How they interact preferentially with naive rather than activated T lymphocytes is still poorly understood. Chemokines direct the transport of white blood cells in immune surveillance. Here we report the identification and characterization of a C-C chemokine (DC-CK1) that is specifically expressed by human dendritic cells at high levels. Tissue distribution analysis demonstrates that dendritic cells present in germinal centres and T-cell areas of secondary lymphoid organs express this chemokine. We show that DC-CK1, in contrast to RANTES, MIP-1alpha and interleukin-8, preferentially attracts naive T cells (CD45RA+). The specific expression of DC-CK1 by dendritic cells at the site of initiation of an immune response, combined with its chemotactic activity for naive T cells, suggests that DC-CK1 has an important rule in the induction of immune responses.

Transmission of bovine spongiform encephalopathy and scrapie to mice: strain variation and the species barrier

Transmissions of bovine spongiform encephalopathy (BSE) from seven unrelated cattle sources have given remarkably uniform disease characteristics in mice, differing from over twenty previous and contemporary transmissions of sheep and goat scrapie. Transmissions to mice of spongiform encephalopathy from six species (including sheep and goats) which have been experimentally or naturally infected with BSE have given similar results to direct BSE transmissions from cattle. Therefore the BSE agent has retained its identity when passaged through a range of species and the 'donor' species has little specific influence on disease characteristics in mice, adding to evidence for an agent-specific informational molecule. On transmission of BSE or scrapie to mice the incubation periods are long compared with subsequent mouse-to-mouse passages (the 'species barrier'). Contributing factors include a low efficiency of infection on interspecies transmission, the apparent failure of intracerebrally injected 'foreign' inoculum to establish infection directly in mouse brain and the selection of variant strains of agent which replicate most readily in the new host species.

PrP genotype and agent effects in scrapie: change in allelic interaction with different isolates of agent in sheep, a natural host of scrapie

Man and sheep are the two species in which spongiform encephalopathies occur naturally, and in which there are recognized genetic components that predispose an individual person or sheep to clinical disease. In both species mutations/polymorphisms in the PrP gene have been linked to the incidence of natural disease, but only in sheep is it possible to investigate by deliberate exposure to infection whether these polymorphisms are directly correlated with survival time. Cheviot sheep of different PrP genotypes were challenged with one of two isolates of scrapie or an isolate of bovine spongiform encephalopathy and the survival time and incidence of disease were monitored. Genotype analysis showed that dimorphisms in codons 136 and 171 of the ovine PrP gene correlated with control of disease incidence and modulation of incubation time. Crucially, the functional effects of these domains of PrP were shown to alternate depending on the isolate of infecting agent.

Vibrio fischeri lux genes play an important role in colonization and development of the host light organ

The bioluminescent bacterium Vibrio fischeri and juveniles of the squid Euprymna scolopes specifically recognize and respond to one another during the formation of a persistent colonization within the host's nascent light-emitting organ. The resulting fully developed light organ contains brightly luminescing bacteria and has undergone a bacterium-induced program of tissue differentiation, one component of which is a swelling of the epithelial cells that line the symbiont-containing crypts. While the luminescence (lux) genes of symbiotic V. fischeri have been shown to be highly induced within the crypts, the role of these genes in the initiation and persistence of the symbiosis has not been rigorously examined. We have constructed and examined three mutants (luxA, luxI, and luxR), defective in either luciferase enzymatic or regulatory proteins. All three are unable to induce normal luminescence levels in the host and, 2 days after initiating the association, had a three- to fourfold defect in the extent of colonization. Surprisingly, these lux mutants also were unable to induce swelling in the crypt epithelial cells. Complementing, in trans, the defect in light emission restored both normal colonization capability and induction of swelling. We hypothesize that a diminished level of oxygen consumption by a luciferase-deficient symbiotic population is responsible for the reduced fitness of lux mutants in the light organ crypts. This study is the first to show that the capacity for bioluminescence is critical for normal cell-cell interactions between a bacterium and its animal host and presents the first examples of V. fischeri genes that affect normal host tissue development.

Paleomagnetic Study of Antarctic Deep-Sea Cores

The magnetic inclinations and inten sities of about 650 samples from seven deepsea cores taken in the Antarctic were measured on a spinner magnetometer. This series of measurements provided a magnetic stratigraphy, based on zones of normally or reversally polar ized specimens for each core, which was then correlated with the magnetic stra tigraphy of Cox et al. (1). One core (V16-134) gave a continuous record of the paleomagnetic field back to about 3.5 million years. When selected samples were subject ed to alternatingfield demagnetization, most were found to have an unstable component that was removed by fields of 150 oersteds; all samples from two cores were partially demagnetized in a field of 150 oersteds. The average inclination in these two cores was then in good agreement with the average inclination of the ambient field for the latitude of the core site. It was also found that the intensities of the samples decreased at the points of reversal; this finding is to be expected if, as has been postulated by the dynamo theory, the intensity of the dipole field decreases to zero and builds again with opposite polarity. We believe that the magnetiza tion of the cores results from the pres ence of detrital magnetite, although other magnetic minerals also may be present. Four faunal zones (, X, , and ) have been recognized in these Antarctic cores on the basis of upward sequential disappearance of Radiolaria. The faunal boundaries and reversals consistently have the same relations to one another, indicating that they are both timedependent phenomena. Using previously determined times of reversal, one may date the following events in the cores: 1) Radiolarian faunal boundaries:-X, 2 million years; X-, 0.7 million years; -, 0.4 to 0.5 million years. These dates are in good agreement with ages previously extrapolated from radio metric dates. 2) Initiation of Antarctic diatom ooze deposition, approximately 2.0 mil-lion years ago. 3) First occurrence of ice- rafted detritus, approximately 2.5 million years ago. One can also calculate rates of sedi mentation, which vary in the cores studied from 1.1 to about 8.0 millimeters per 1000 years. Sedimentation rates for the Indian Ocean cores are higher than for the Bellingshausen Sea cores. The near coincidence of faunal changes and reversals in the cores suggests but does not prove a causal relation. We conclude from this study that paleomagnetic stratigraphy is a unique method for correlating and dating deep sea cores, and that future work with such cores may provide a complete or nearly complete record of the history of the earth's magnetic field beyond 4 million years.

Cloning and characterization of IL-17B and IL-17C, two new members of the IL-17 cytokine family

IL-17 is a T cell-derived cytokine that may play an important role in the initiation or maintenance of the proinflammatory response. Whereas expression of IL-17 is restricted to activated T cells, the IL-17 receptor is found to be widely expressed, a finding consistent with the pleiotropic activities of IL-17. We have cloned and expressed two novel human cytokines, IL-17B and IL-17C, that are related to IL-17 ( approximately 27% amino acid identity). IL-17B mRNA is expressed in adult pancreas, small intestine, and stomach, whereas IL-17C mRNA is not detected by RNA blot hybridization of several adult tissues. No expression of IL-17B or IL-17C mRNA is found in activated T cells. In a survey of cytokine induction, IL-17B and IL-17C stimulate the release of tumor necrosis factor alpha and IL-1beta from the monocytic cell line, THP-1, whereas IL-17 has only a weak effect in this system. No induction of IL-1alpha, IL-6, IFN-gamma, or granulocyte colony-stimulating factor is found in THP-1 cells. Fluorescence-activated cell sorter analysis shows that IL-17B and IL-17C bind to THP-1 cells. Conversely, IL-17B and IL-17C are not active in an IL-17 assay or the stimulation of IL-6 release from human fibroblasts and do not bind to the human IL-17 receptor extracellular domain. These data show that there is a family of IL-17-related cytokines differing in patterns of expression and proinflammatory responses that may be transduced through a cognate set of cell surface receptors.

Random amplified polymorphic DNA typing of Pseudomonas aeruginosa isolates recovered from patients with cystic fibrosis

Pseudomonas aeruginosa isolates recovered from chronically colonized patients with cystic fibrosis (CF) are phenotypically different from those collected from other patients or from the environment. To assess whether alterations in motility, mucoidy, and serum susceptibility represented an adaptation to chronic infection or replacement by a new strain, sequential P. aeruginosa isolates of known phenotype collected from 20 CF patients were typed by random amplified polymorphic DNA (RAPD) analysis. A total of 35 RAPD strain types were found among 385 isolates from 20 patients, and only two patients had P. aeruginosa strains of the same RAPD fingerprint. Eight strain pairs representative of the first eight RAPD types were also analyzed by SpeI macrorestriction followed by pulsed-field gel electrophoresis (PFGE); the strain types found by both fingerprinting techniques correlated exactly. In 11 of 20 patients, the RAPD types of serial P. aeruginosa isolates remained stable despite alterations in isolate motility, colonial morphology, and lipopolysaccharide phenotype. However, in isolates collected from one CF patient, a single band change in RAPD fingerprint and CeuI PFGE profile correlated with the appearance of an RpoN mutant phenotype, suggesting that the altered phenotype may have been due to a stable genomic rearrangement. Secretion of mucoid exopolysaccharide, loss of expression of RpoN-dependent surface factors, and acquisition of a serum-susceptible phenotype in P. aeruginosa appear to evolve during chronic colonization in CF patients from specific adaptation to infection rather than from acquisition of new bacterial strains.

FGF-19, a novel fibroblast growth factor with unique specificity for FGFR4

We have identified a novel fibroblast growth factor, FGF-19, the most distant member of the FGF family described to date. FGF-19 is a high affinity, heparin dependent ligand for FGFR4 and is the first member of the FGF family to show exclusive binding to FGFR4. Human FGF-19 maps to chromosome 11 q13.1, a region associated with an osteoporosis-pseudoglioma syndrome of skeletal and retinal defects. FGF-19 message is expressed in several tissues including fetal cartilage, skin, and retina, as well as adult gall bladder and is overexpressed in a colon adenocarcinoma cell line.

Macrophages sustain HIV replication in vivo independently of T cells

Macrophages have long been considered to contribute to HIV infection of the CNS; however, a recent study has contradicted this early work and suggests that myeloid cells are not an in vivo source of virus production. Here, we addressed the role of macrophages in HIV infection by first analyzing monocytes isolated from viremic patients and patients undergoing antiretroviral treatment. We were unable to find viral DNA or viral outgrowth in monocytes isolated from peripheral blood. To determine whether tissue macrophages are productively infected, we used 3 different but complementary humanized mouse models. Two of these models (bone marrow/liver/thymus [BLT] mice and T cell-only mice [ToM]) have been previously described, and the third model was generated by reconstituting immunodeficient mice with human CD34+ hematopoietic stem cells that were devoid of human T cells (myeloid-only mice [MoM]) to specifically evaluate HIV replication in this population. Using MoM, we demonstrated that macrophages can sustain HIV replication in the absence of T cells; HIV-infected macrophages are distributed in various tissues including the brain; replication-competent virus can be rescued ex vivo from infected macrophages; and infected macrophages can establish de novo infection. Together, these results demonstrate that macrophages represent a genuine target for HIV infection in vivo that can sustain and transmit infection.

Social cognition in frontotemporal dementia and Huntington's disease

Frontotemporal dementia (FTD) and Huntington's disease (HD) are degenerative disorders, with predominant involvement, respectively of frontal neocortex and striatum. Both conditions give rise to altered social conduct and breakdown in interpersonal relationships, although the factors underlying these changes remain poorly defined. The study used tests of theory of mind (interpretation of cartoons and stories and judgement of preference based on eye gaze) to explore the ability of patients with FTD and HD to interpret social situations and ascribe mental states to others. Performance in the FTD group was severely impaired on all tasks, regardless of whether the test condition required attribution of a mental state. The HD group showed a milder impairment in cartoon and story interpretation, and normal preference judgements. Qualitative differences in performance were demonstrated between groups. FTD patients made more concrete, literal interpretations, whereas HD patients were more likely to misconstrue situations. The findings are interpreted as demonstrating impaired theory of mind in FTD, as one component of widespread executive deficits. In HD the evidence does not suggest a fundamental loss of theory of mind, but rather a tendency to draw faulty inferences from social situations. It is concluded that social breakdown in FTD and HD may have a different underlying basis and that the frontal neocortex and striatum have distinct contributions to social behaviour.

Aurora kinase inhibitor nanoparticles target tumors with favorable therapeutic index in vivo

Efforts to apply nanotechnology in cancer have focused almost exclusively on the delivery of cytotoxic drugs to improve therapeutic index. There has been little consideration of molecularly targeted agents, in particular kinase inhibitors, which can also present considerable therapeutic index limitations. We describe the development of Accurin polymeric nanoparticles that encapsulate the clinical candidate AZD2811, an Aurora B kinase inhibitor, using an ion pairing approach. Accurins increase biodistribution to tumor sites and provide extended release of encapsulated drug payloads. AZD2811 nanoparticles containing pharmaceutically acceptable organic acids as ion pairing agents displayed continuous drug release for more than 1 week in vitro and a corresponding extended pharmacodynamic reduction of tumor phosphorylated histone H3 levels in vivo for up to 96 hours after a single administration. A specific AZD2811 nanoparticle formulation profile showed accumulation and retention in tumors with minimal impact on bone marrow pathology, and resulted in lower toxicity and increased efficacy in multiple tumor models at half the dose intensity of AZD1152, a water-soluble prodrug of AZD2811. These studies demonstrate that AZD2811 can be formulated in nanoparticles using ion pairing agents to give improved efficacy and tolerability in preclinical models with less frequent dosing. Accurins specifically, and nanotechnology in general, can increase the therapeutic index of molecularly targeted agents, including kinase inhibitors targeting cell cycle and oncogenic signal transduction pathways, which have to date proved toxic in humans.

Consensus guidelines from The American Society of Peritoneal Surface Malignancies on standardizing the delivery of hyperthermic intraperitoneal chemotherapy (HIPEC) in colorectal cancer patients in the United States

BACKGROUND

The American Society of Peritoneal Surface Malignancies (ASPSM) is a consortium of cancer centers performing cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC). This is a position paper from the ASPSM on the standardization of the delivery of HIPEC.

METHODS

A survey was conducted of all cancer centers performing HIPEC in the United States. We attempted to obtain consensus by the modified method of Delphi on seven key HIPEC parameters: (1) method, (2) inflow temperature, (3) perfusate volume, (4) drug, (5) dosage, (6) timing of drug delivery, and (7) total perfusion time. Statistical analysis was performed using nonparametric tests.

RESULTS

Response rates for ASPSM members (n = 45) and non-ASPSM members (n = 24) were 89 and 33 %, respectively. Of the responders from ASPSM members, 95 % agreed with implementing the proposal. Majority of the surgical oncologists favored the closed method of delivery with a standardized dual dose of mitomycin for a 90-min chemoperfusion for patients undergoing cytoreductive surgery for peritoneal carcinomatosis of colorectal origin.

CONCLUSIONS

This recommendation on a standardized delivery of HIPEC in patients with colorectal cancer represents an important first step in enhancing research in this field. Studies directed at maximizing the efficacy of each of the seven key elements will need to follow.

HIV-1 Nef: at the crossroads

The development of anti-virals has blunted the AIDS epidemic in the Western world but globally the epidemic has not been curtailed. Standard vaccines have not worked, and attenuated vaccines are not being developed because of safety concerns. Interest in attenuated vaccines has centered on isolated cases of patients infected with HIV-1 containing a deleted nef gene. Nef is a multifunctional accessory protein that is necessary for full HIV-1 virulence. Unfortunately, some patients infected with the nef-deleted virus eventually lose their CD4⁺ T cells to levels indicating progression to AIDS.

This renders the possibility of an attenuated HIV-1 based solely on a deleted nef remote. In this review we discuss the knowledge gained both from the study of these patients and from in vitro investigations of Nef function to assess the possibility of developing new anti-HIV-1 drugs based on Nef. Specifically, we consider CD4 downregulation, major histocompatibility complex I downregulation, Pak2 activation, and enhancement of virion infectivity. We also consider the recent proposal that simian immunodeficiency viruses are non-pathogenic in their hosts because they have Nefs that downregulate CD3, but HIV-1 is pathogenic because its Nef fails to downregulate CD3. The possibility of incorporating the CD3 downregulation function into HIV-1 Nef as a therapeutic option is also considered. Finally, we conclude that inhibiting the CD4 downregulation function is the most promising Nef-targeted approach for developing a new anti-viral as a contribution to combating AIDS.

Microsomal cytochrome P-452 induction and peroxisome proliferation by hypolipidaemic agents in rat liver. A mechanistic inter-relationship

Eight structurally diverse hypolipidaemic agents have been examined for their ability to induce the microsomal cytochrome P-452-dependent fatty acid hydroxylase system and the enzymes of peroxisomal beta-oxidation in rat liver. Using a specific ELISA method, we have shown that the cytochrome P-452 isoenzyme is induced up to ten fold by hypolipidaemic challenge, concomitant with a pronounced elevation of the peroxisomal beta-oxidation enzymes, mirrored by an increase in peroxisomal volume as determined morphometrically. In addition, the induction of cytochrome P-452 is accompanied by a decrease in the activities of cytochromes P-450b and P-450c as measured by benzphetamine N-demethylase and ethoxyresorufin O-deethylase activities respectively, the latter being more extensively reduced by hypolipidaemic treatment. A hypothesis is presented whereby an early biological response is the hypolipidaemic induction of microsomal cytochrome P-452 resulting in omega-hydroxy fatty acids and their subsequent further oxidation to dicarboxylic acids, the latter providing the proximal stimulus for peroxisomal proliferation.

Forced expression of murine IL-17E induces growth retardation, jaundice, a Th2-biased response, and multiorgan inflammation in mice

IL-17 is a proinflammatory cytokine, and its in vivo expression induces neutrophilia in mice. IL-17E is a recently described member of an emerging family of IL-17-related cytokines. IL-17E has been shown to bind IL-17Rh1, a protein distantly related to the IL-17R, suggesting that IL-17E probably possesses unique biological functions. In this study, we have identified the murine ortholog of IL-17E and developed transgenic mice to characterize its actions in vivo. Biological consequences of overexpression of murine (m)IL-17E, both unique to IL-17E and similar to IL-17, were revealed. Exposure to mIL-17E resulted in a Th2-biased response, characterized by eosinophilia, increased serum IgE and IgG1, and a Th2 cytokine profile including elevated serum levels of IL-13 and IL-5 and elevated gene expression of IL-4, IL-5, IL-10, and IL-13 was observed in many tissues. Increased gene expression of IFN-gamma in several tissues and elevated serum TNF-alpha were also noted. In addition, IL-17E induces G-CSF production in vitro and mIL-17E-transgenic mice had increased serum G-CSF and exhibit neutrophilia, a property shared by IL-17. Moreover, exposure to mIL-17E elicited pathological changes in multiple tissues, particularly liver, heart, and lungs, characterized by mixed inflammatory cell infiltration, epithelial hyperplasia, and hypertrophy. Taken together, these findings suggest that IL-17E is a unique pleiotropic cytokine and may be an important mediator of inflammatory and immune responses.

Novel polymorphisms in the caprine PrP gene: a codon 142 mutation associated with scrapie incubation period

Age at disease onset and rate of progression of transmissible spongiform encephalopathies in man, sheep and mice are modulated by the host genome, in particular by the PrP gene and its allelic forms. Analysis of the caprine PrP gene revealed several different alleles. Four PrP protein variants were found, three of which were goat specific with single amino acid changes at codons 142, 143 and 240. The fourth was identical to the most common sheep PrP protein variant (Ala136-Arg154-Gln171). The dimorphism at codon 142 (Ile --> Met) appeared to be associated with differing disease incubation periods in goats experimentally infected with isolates of bovine spongiform encephalopathy, sheep scrapie CH1641 or sheep-passaged ME7 scrapie.

Dual-task effects of talking while walking on velocity and balance following a stroke

BACKGROUND

Therapists and nurses often use verbal instruction in the rehabilitation of mobility following stroke. This study aimed to determine whether performing a verbal cognitive task while walking adversely affected patients' balance and velocity.

METHODS

There were two counterbalanced conditions: walking only and walking and concurrent cognitive activity. The cognitive activity used was to give one of two verbal responses to two verbal stimuli. An electronic GaitMat measured gait velocity and balance (double support time as a percentage of stride time).

RESULTS

11 people with stroke participated in the study (five women and six men, mean age 72 years, SD 9). They were on average 120 (SD 48) days post-stroke. Velocity decreased (P=0.017) and double-support time as a percentage of stride time increased (P=0.010) when the cognitive activity was added to the test.

CONCLUSIONS

Performing a verbal cognitive task while walking adversely affected stroke patients' balance and gait velocity. Susceptibility to disruption varied within the patient group, suggesting clinical heterogeneity. Further research is required before changes to clinical practice are justified.

Acinar cells of the pancreas are a target of interleukin-22

Interleukin-22 (IL-22) (also reported as IL-10-related T cell-derived inducible factor, IL-TIF) is a recently identified cytokine found to signal through a receptor comprising the class II cytokine receptor family members IL-10Rbeta/CRF2-4 and IL-22R. Previous work has established that IL-10Rbeta, also a component of the IL10R complex, exhibits a broad distribution of mRNA expression. Here, we observe that IL-22R exhibits a restricted expression pattern, with highest levels of mRNA expression in pancreas and detectable expression in multiple other tissues, particularly liver, small intestine, colon, and kidney. We find that isolated primary pancreatic acinar cells and the acinar cell line 266-6 respond to IL-22 with activation of Stat3 and changes in gene transcription. IL-22 mediates robust induction of mRNA for pancreatitis-associated protein (PAP1)/Reg2 and osteopontin (OPN). PAP1 is a secreted protein related to the Reg family of trophic factors and was initially characterized as a protein elevated in pancreatitis. In vivo injection of IL-22 resulted in rapid induction of PAP1 in pancreas, a response not observed in mice deficient in IL-10Rbeta. These results support the conclusion that IL-10Rbeta is a required common component of both the IL-10 and IL-22 receptors and suggest that IL-22 may play a role in the immune response in pancreas.

An immunoglobulin promoter displays cell-type specificity independently of the enhancer

Recent studies in which cloned immunoglobulin genes were introduced into cultured cells have produced two significant findings. First, the genes are expressed after transfection into lymphoid cells but not non-lymphoid cells. Second, transcription of an immunoglobulin gene requires, in addition to the promoter region, an enhancer element located downstream of the transcription start site. These findings raise the question of whether it is the promoter or the enhancer region that is responsible for the observed cell-type specificity. It has, in fact, been shown that immunoglobulin enhancers function only in lymphoid cells. We show here that the promoter for an immunoglobulin kappa light-chain gene also is strongly specific for lymphoid cells. Our result reemphasizes the importance of promoters relative to enhancers in determining which cells express which genes.

Ventricular mass index using magnetic resonance imaging accurately estimates pulmonary artery pressure

Magnetic resonance imaging (MRI) can provide accurate anatomical measurements of the cardiac ventricles. This study investigated whether a calculated ventricular mass index (VMI) would provide an accurate means of estimating pulmonary artery pressure noninvasively, and compared the results with conventional Doppler echocardiography and invasive measurement. A total of 26 subjects referred for investigation of pulmonary hypertension were studied by MRI and echocardiography within 2 weeks of cardiac catheterisation. The correlations for mean pulmonary artery pressure were as follows: VMI (ratio of right ventricular mass over left ventricular mass) r=0.81; pulmonary artery systolic pressure (echocardiography) r=0.77. The confidence intervals for the VMI were narrower than for echocardiography. Sensitivity and specificity for pulmonary hypertension were 84 and 71% respectively for the VMI compared with 89 and 57% for echocardiography. The calculated ventricular mass index provides an accurate and practical means of estimating pulmonary artery pressure noninvasively in pulmonary hypertension and may provide a more accurate estimate than Doppler echocardiography. This may be because it reflects the right ventricular response to sustained pulmonary hypertension over a long period and is not influenced by short-term physiological variables affecting echocardiography, such as heart rate, posture, hydration status and oxygen supplementation.