CD10+ Cells and IgM in Pathogen Response in Lumpfish (Cyclopterus lumpus) Eye Tissues

Lumpfish (Cyclopterus lumpus), a North Atlantic “cleaner“ fish, is utilized to biocontrol salmon louse (Lepeophtheirus salmonis) in Atlantic salmon (Salmo salar) farms. Lumpfish require excellent vision to scan for and eat louse on salmon skin. The lumpfish eye immune response to infectious diseases has not been explored. We examined the ocular response to a natural parasite infection in wild lumpfish and to an experimental bacterial infection in cultured lumpfish. Cysts associated with natural myxozoan infection in the ocular scleral cartilage of wild adult lumpfish harbored cells expressing cluster of differentiation 10 (CD10) and immunoglobulin M (IgM). Experimental Vibrio anguillarum infection, which led to exophthalmos and disorganization of the retinal tissues was associated with disruption of normal CD10 expression, CD10⁺ cellular infiltration and IgM expression. We further describe the lumpfish CD10 orthologue and characterize the lumpfish scleral skeleton in the context of myxozoan scleral cysts. We propose that lumpfish develop an intraocular response to pathogens, exemplified herein by myxozoan and V. anguillarum infection involving novel CD10⁺ cells and IgM⁺ cells to contain and mitigate damage to eye structures. This work is the first demonstration of CD10 and IgM expressing cells in a novel ocular immune system component in response to disease in a teleost.

Aeromonas salmonicida infection kinetics and protective immune response to vaccination in sablefish (Anoplopoma fimbria)

Effective vaccine programs against Aeromonas salmonicida have been identified as a high priority area for the sablefish (Anoplopoma fimbria) aquaculture. In this study, we established an A. salmonicida infection model in sablefish to evaluate the efficacy of commercial vaccines and an autogenous vaccine preparation. Groups of 40 fish were intraperitoneally (ip) injected with different doses of A. salmonicida J410 isolated from infected sablefish to calculate the median lethal dose (LD₅₀). Samples of blood, head kidney, spleen, brain, and liver were also collected at different time points to determine the infection kinetics. The LD₅₀ was estimated as ~3 × 10⁵ CFU/dose. To evaluate the immune protection provided by an autogenous vaccine and two commercial vaccines in a common garden experimental design, 140 fish were PIT-tagged, vaccinated and distributed equally into 4 tanks (35 fish for each group, including a control group). Blood samples were taken every 2 weeks to evaluate IgM titers. At 10 weeks post-immunization, all groups were ip challenged with 100 times the calculated LD₅₀ for A. salmonicida J410. A. salmonicida was detected after 5 days post-infection (dpi) in all collected tissues. At 30 days post-challenge the relative percentage survival (RPS) with respect to the control group was calculated for each vaccine. The RPS for the bacterin mix was 65.22%, for Forte Micro 4® vaccine was 56.52% and for Alpha Ject Micro 4® was 30.43%, and these RPS values were reflected by A. salmonicida tissue colonization levels at 10 days post-challenge. Total IgM titers peaked at 6-8 weeks post-immunization, where the autogenous vaccine group showed the highest IgM titers and these values were consistent with the RPS data. Also, we determined that the A. salmonicida A-layer binds to immunoglobulins F(ab)' in a non-specific fashion, interfering with immune assays and potentially vaccine efficacy. Our results indicate that vaccine design influences sablefish immunity and provide a guide for future sablefish vaccine programs.

Measurement of Tissue Factor Activity in Whole Blood

High circulating levels of the procoagulant molecule tissue factor (TF) are associated with thrombosis in a variety of diseases including unstable angina, cancer, and sepsis. Currently, there are no clinical assays to measure the level of TF activity in whole blood. We present an assay called Tissue Factor Clotting Time (“TiFaCT™”) that detects fibrin formation in human blood. The mean baseline clotting time in a healthy population was 472 ± 94 s (mean ± SD, n = 150). Bacterial lipopolysaccharide (LPS or endotoxin) shortened the clotting time in a time-dependent manner. Inhibitory anti-TF antibodies prolonged the clotting time of LPS-stimulated blood, indicating that the shortened clotting time was due to induction of TF expression. Patients with unstable angina had shortened mean baseline clotting time (284 ± 86, n = 13) compared with healthy volunteers (474 ± 98, n = 30), suggesting that these patients had elevated levels of circulating TF. The TiFaCT assay should prove clinically useful in quantifying the levels of circulating TF in patients at risk of thrombosis.

Change in paternity and select perinatal outcomes: causal or confounded?

Select social, behavioural and maternal characteristics were evaluated to determine if they were confounding factors in the association between paternity change and pre-eclampsia, small for gestational age (SGA) and pre-term delivery, in a sample of 1,409 women. Multivariate logistic regression analysis was used to determine if any of these risk factors modified the association between changing paternity and the selected perinatal outcomes. Results of the analysis showed that women who changed partners were more likely to possess potentially confounding risk factors compared with those who had not. Paternity change was 2.75 times more likely to be associated with the development of pre-eclampsia (95% CI 1.33; 5.68) and 2.25 times more likely to be associated with an SGA infant on weight (95% CI 1.13; 4.47), after adjusting for selected risk factors. Paternity change remains a significant risk factor for pre-eclampsia and SGA in the presence of select risk factors.

Experience establishing tuberculosis laboratory capacity in a developing country setting

OBJECTIVE

To describe the experience of strengthening laboratory diagnosis of tuberculosis (TB) in a resource-limited country with high TB-HIV (human immunodeficiency virus) and multidrug-resistant TB (MDR-TB) prevalence.

METHODS

In the Kingdom of Lesotho, which is confronted with high levels of TB, MDR-TB and HIV prevalence, between 2006 and 2008 a coalition of the Foundation for Innovative New Diagnostics, Partners In Health and the World Health Organization renovated the National TB Reference Laboratory and reinforced microscopy services, streamlined conventional culture and drug susceptibility testing (DST) and introduced modern TB diagnostic methods.

FINDINGS

It was feasible to establish a biosafety level three facility for solid culture and DST and an external quality assessment programme for smear microscopy within 4 months, all in 2007. Liquid culture and DST were introduced a month later. Preliminary results were comparable to those found in laboratories in industrialised countries. A year later, line-probe assay for the rapid detection of MDR-TB was introduced.

DISCUSSION

Through strong political commitment and collaboration, it is possible to rapidly establish quality assured TB diagnostic capacity, including current methods, in a resource-limited setting. Case detection and management for TB and MDR-TB have been greatly enhanced. From a low baseline, TB culture throughput in the laboratory increased ten-fold and has been sustained. This experience has served as a catalyst to translate policy into practice with new diagnostic technologies. It supports global policy setting to enhance and modernise laboratory work in developing countries.

Genotypic stability of cold-adapted influenza virus vaccine in an efficacy clinical trial

An investigational live influenza virus vaccine, FluMist, contains three cold-adapted H1N1, H3N2, and B influenza viruses. The vaccine viruses are 6/2 reassortants, in which the hemagglutinin (HA) and neuraminidase (NA) genes are derived from the circulating wild-type viruses and the remaining six genes are derived from the cold-adapted master donor strains. The six genes from the cold-adapted master donor strains ensure the attenuation, and the HA and NA genes from the wild-type viruses confer the ability to induce protective immunity against contemporary influenza strains. The genotypic stability of this vaccine was studied by employing clinical samples collected during an efficacy trial. Viruses present in the nasal and throat swab specimens and in supernatants after culturing the specimens were detected and subtyped by multiplex reverse transcriptase (RT)-PCR. Complete genotypes of these detected viruses were determined by a combination of RT-PCR and restriction fragment length polymorphism, multiplex RT-PCR and fluorescent single-strand conformation polymorphism, and nucleic acid sequencing analysis. The FluMist vaccine appeared to be genotypically stable after replication in the human host. All viruses detected during the 2-week postvaccination period were shed vaccine viruses and had maintained the 6/2 genotype.

Overexpression of a novel Xenopus rel mRNA gene induces tumors in early embryos

The Rel family of transcriptional activators form a large diverse group of proteins that are involved in the activation of genes involved in immunity, development, apoptosis and cancer. So far, none of the rel genes cloned in mammals appear to be required for embryonic development. We have cloned and characterized a cDNA from an embryonic cDNA library that encodes a novel Xenopus Rel protein, called Xrel3. Xrel3 is a member of the cRel subfamily and is most closely related to but distinct from other Xenopus Rel members. The expression of Xrel3 mRNA was investigated using Northern analysis, RNase protection assay, reverse transcriptase-linked polymerase chain reaction and in situ hybridization. Messages are present maternally and are slightly enriched in the equatorial region of the blastula stage embryo. At gastrulation, the accumulation of Xrel3 messages declines to undetectable levels but then increases after neurulation. In situ RNA hybridization was used to determine the spatial location of Xrel3 messenger RNA in embryos. Messages are localized to the developing forebrain, dorsal mid-hindbrain region, the inner ear primordium, or otocyst, and in the notochord. Overexpression by microinjection of Xrel3 RNA induced tumors in the developing embryo that appeared after gastrulation. The location of the tumors depended on the location of the injection site. These results suggest that Xrel3 might have a generalized role in regulation of cell differentiation in the embryo.

Physiological evidence for hippocampal disinhibition resulting from activation of the median raphe

The mechanism underlying median raphe (MR)-induced facilitation of hippocampal synaptic transmission was investigated by recording stimulus-evoked field potentials and unitary responses in urethane-anesthetized rats. Stimulation of the MR 40 ms prior to perforant path (PP) activation significantly increased the magnitude of PP-evoked granule cell population spikes (median increase = 78%) without affecting population EPSP slope. Injection of homocysteic acid into the vicinity of the MR also facilitated PP-evoked granule cell population spikes, in a dose-dependent manner. Nineteen dentate hilar units were characterized as putative interneurons on the basis of their waveform characteristics and their response to PP stimulation. Electrical activation of the MR inhibited spontaneous or PP-evoked activity in the majority (75%) of these cells; the remaining cells were unaffected. MR stimulation also inhibited spontaneous activity in a large proportion (60%) of putative interneurons in CA1. The present results provide evidence that neurons within the raphe modulate hippocampal throughput by altering discharge of non-principal cells. These data, thus, support the idea that disinhibition is a common mechanism by which extrahippocampal structures modulate information flow through the hippocampus.

Muscle gene activation in Xenopus requires intercellular communication during gastrula as well as blastula stages

In Xenopus an early morphological marker of mesodermal induction is the elongation of the mesoderm at the early gastrula stage (Symes and Smith, 1987). We show here that the elongation of equatorial (marginal) tissue is dependent on protein synthesis in a mid blastula, but has become independent of it by the late blastula stage. In animal caps induced to become mesoderm, the time when protein synthesis is required for subsequent elongation immediately follows the time of induction, and is not related to developmental stage. For elongation, intercellular communication during the blastula stage is of primary importance.

Current experiments involving cell transplantation indicate a need for further celhcell interactions during gastrulation, and therefore after the vegetal-animal induction during blastula stages. These secondary cell interactions are believed to take place among cells that have already received a vegetal induction, and may facilitate some of the later intracellular events known to accompany muscle gene activation.

Generation of body plan phenotypes in early embryogenesis

We have presented a number of simple methods that can be used to interfere in the normal establishment and subsequent development of dorsal axial structures in Xenopus. It should be emphasized that, despite the striking similarity in phenotypes which result from these treatments, different developmental processes are being affected at the different windows of sensitivity. For example, UV light, known to damage RNA (for review, see Kalthoff, 1979), also disrupts microtubule polymerization. These activities may be important at different developmental times, relating to the distribution of maternal determinants (in the oocyte) or to the coordinated assembly of cortical microtubules (in the just-fertilized egg). The ventralizing and dorsalizing effects of the various late-acting agents (e.g., TB, suramin, RA, GV sap) undoubtedly stem from their interference with cellular behaviors during the critical morphogenetic period of gastrulation.

Lesions of substantia nigra retard pavlovian somatomotor learning but do not affect autonomic conditioning

New Zealand albino rabbits with bilateral radio frequency lesions of the substantia nigra (SN) were compared with sham-operated animals on a pavlovian conditioning task in which eyeblink (EB) and heart rate (HR) responses were concomitantly assessed. Lesions of SN increased the number of trials required to reach an EB learning criterion but left the HR conditioned response intact. These results together with other reports in the literature suggest that extrapyramidal motor structures are involved in mediating somatomotor conditioning but are not involved in autonomic learning.