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GABA, glutamate and beyond : in vivo measures and models of neurochemistry and network dynamics in healthy subjects and clinical populationsShaw, Alexander January 2014 (has links)
Major depressive disorder (MDD) is a chronic, recurrent mood disorder (Kendler, Thornton, & Gardner, 2000; Kumar, Harmer, & Dourish, 2013) with an estimated lifetime prevalence of 16.2% (Kessler et al., 2003) which affects more than 350 million people globally (WHO, 2013). MDD has a complicated and multifarious neuropathology, a result of which is largely ineffective and out-dated pharmacological treatments (Skolnick, 1999). Typical antidepressants are either serotonin re-uptake inhibitors (SRI) or tri-cyclic antidepressants (TCA), both of which target the monoamine system (serotonin and/or dopamine). However, research has suggested a myriad of distinct hypotheses for depression through localisation of functionally distinct neuroanatomical structures, identification of neurotransmitter modulation and receptor subunit alterations as well as genetic, environmental and behavioural observations that could all be targets for antidepressant therapy. Alterations of the GABAergic and glutamatergic neurotransmitter systems have been reported in major depressive disorder (MDD), both post-mortem in-vitro and ante-mortem in-vivo. Evidence from magnetic resonance spectroscopy (MRS) studies reported lower bulk concentrations of GABA in currently depressed participants as compared with healthy controls, which may reflect a neurobiological pathology, serve as a biomarker, and guide development of new pharmacological therapies. If this area of research is to see translation to a clinical setting, the roles of GABA (and glutamate) in depression need to be fully elucidated. Some of the questions that arise are: Do alterations in GABA concentration reflect state or trait markers of depression? Does the GABA deficit observed in depression reflect ‘functional’ GABA? Does an existing pharmacological compound with antidepressant efficacy act on the GABA system? This thesis addresses these questions primarily utilizing multimodal neuroimaging techniques, along with computational neuronal modelling and pharmacological manipulation.
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Investigating the role of T-cells in chronic lymphocytic leukemiaReed, Reiss January 2015 (has links)
T-cells appear to have multiple conflicting roles in CLL. On the one hand tumour-specific T-cells could be used to deliver effective immunotherapy; on the other hand, certain T-cell populations may enhance CLL survival and disease progression. The aim of this thesis was to address these contradictory aspects and to provide a deeper understanding of the role of T-cells in CLL. Firstly, candidate peptides from the pro-apoptotic protein Bax were used to activate potential CLL specific T-cells from HLA-A2+ patients. A CD8+ T-cell clone (6C5) was isolated and it’s specificity was initially mapped to (Bax161-170; LLSYFGTPT) and(Bax160–170; GLLSYFGTPT). However, 6C5 failed to recognise HLA-A2+ CLL cells in vitro, and failed to recognise highly purified forms of the peptides. Further characterisation, involving mass spectrometry and HPLC, mapped T-cell specificity to a modified peptide (LLSY(3-tBu)FGTPT). A second strand of this project involved detailed phenotypic analysis of T-cells from CLL patients (n=97) in order to investigate the basis for immune dysfunction. This analysis indicated that patients with an inverted CD4:CD8 ratio (CLLIR), displayed a skewing towards a highly differentiated T-cell phenotype, as well as expression of markers associated with replicative senescence (CD57+, CD27-) within CD4+ and CD8+ T-cell compartments. In addition, CD4+ T-cells expressing markers associated with immunosuppression (PD-1+, TIM-3+) were also increased in CLLIR. Importantly, the inversion of the CD4:CD8 ratio was associated with shorter progression-free survival. Furthermore, the frequencies of distinct T-cell populations were also shown to haveprognostic impact in both univariate analysis (CD4+PD-1+, CD4+CD57+, CD8+CD57+ and CD8+CD27-) and multivariate analysis (CD4+CD27-PD-1+LAG-3+ and CD8+CD27- CD57+PD-1+). To further evaluate the differences between CLLIR and CLLNR patients, preliminary transcriptional analysis was performed, focusing on genes associated with T-cell function. By contrast, transcriptional analysis suggested that genes associated with activation rather than suppression were enriched in CLLIR.
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Is there evidence of social inequity in healthcare for coronary heart disease? : an electronic-cohort analysis using record-linked, routine dataKing, William January 2015 (has links)
This study aimed to establish whether there was evidence of inequity in the utilisation of healthcare for coronary heart disease in the population of Wales during the period 2004 to 2010. Determining whether or not such inequity exists is important, because equity in healthcare is an aim of NHS services and, if present, inequity might contribute to the substantial differences in coronary-heart-disease mortality by deprivation that are seen in Wales. I used linked general practice, hospital admission, and mortality data from routine sources, and developed a distinctive methodology to evaluate the utilisation, timeliness, and maintenance of appropriate treatment, making comparisons across deprivation quintiles. My approach was based on analysing a pathway of care for coronary heart disease in a comprehensive way. At each stage in this pathway I examined ‘clinical triggers’ and the extent to which these were matched by appropriate ‘clinical actions’. Findings were broadly in accord with those in the published literature: using multivariate adjustment and taking account of supplyside- effects using frailty models, I detected no systematic evidence of inequity in coronary-heart-disease healthcare provision except in relation to revascularisation. As an illustration of this broad pattern, I found that the adjusted hazard ratio for times-to-receiving revascularisation in the most deprived quintile (compared to the least) was 0.83 (95% confidence interval 0.77; 0.91) in those with myocardial infarction. Further, I found no evidence that indicated prescriptions were reissued over a shorter time-period for more deprived individuals. In discussing this work, I consider possible explanations for my findings, and address the way that my distinctive methodology, which enabled measurement of important aspects of coronary-heart-disease care, might be applied in other areas. This work has important implications in demonstrating in a systematic and comprehensive way that healthcare inequity for coronary heart disease in the NHS is confined to specific interventions, and is unlikely to be contributing substantially to differences in mortality between deprivation groups.
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The interaction of transforming growth factor beta and pro-inflammatory signalling in peritoneal fibrosisBodenham, Tanya Jayne January 2015 (has links)
Peritoneal fibrosis is a significant problem for peritoneal dialysis patients resulting in a loss in membrane dialysing capacity ultimately leading to technique failure. The development of peritoneal fibrosis is attributed to recurrent peritonitis infections and bio-incompatible dialysate fluid, both of which contribute to a chronic inflammatory state within the peritoneum. Transforming growth factor beta 1 (TGF-β1) is a cytokine with a central role in peritoneal fibrosis. However, this cytokine has multiple key roles, including development, wound healing cell proliferation and differentiation and regulation of the immune response. Cellular response to TGF-β1 can vary depending on cellular context and phenotype. Factors governing responses to TGF-β1 within the peritoneum are poorly characterised. Previous research through a murine model representing inflammation driven fibrosis has identified Interferon gamma (IFN-γ) having a central role in inflammation driven fibrosis. Therefore examination of the interaction between TGFβ1 and IFN-γ were undertaken in both murine samples and primary human peritoneal cells (HPMC). Within the SES murine model differences in TGF-β1 responses were observed between WT and IL6KO mice, with WT mice displaying significant increase in expression of TGF-β1 and matrix genes. There was increased expression of matrix metalloproteinases 3 and 10 (MMP3 and MMP10) in 116K0 mice, suggesting that these mice are protected against scarring and fibrosis through enhanced tissue remodelling. Similar findings were observed in HPMC treated with TGF-β1 alone resulting in significant increased MMP3 expression, which was inhibited in the presence of IFN-γ. IFN-γ did not affect any other TGF-β1 induced responses thus suggesting a specific fibrotic effect of IFN-γ within this system by inhibiting matrix degradation. Analysis of the mechanism of MMP3 regulation by TGF-β1 and IFN-γ revealed that SMAD and MAPK pathways are involved in the induction of MMP3 by TGF-β1 and are not inhibited by IFN-γ. Analysis of the AP-1 promoter site in the MMP3 revealed that this site may be involved in basal MMP3 expression but is not modulated by TGF-β1 and IFN-γ. Further examination of MMP3 regulation may provide a potential target in helping protect against peritoneal fibrosis, thus helping reduce technique failure in peritoneal dialysis.
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Antigenic ureaplasma variation and adaptation to ovine complement response following experimental intrauterine infectionAhmed, Shatha Thanoon January 2015 (has links)
Ureaplasma parvum is one of the smallest (genome <0.8 Mb), free living, self-replicating organisms identified. There are seven species of Ureaplasma but only two infect humans: Ureaplasma parvum (serovars 1, 3, 6 and 14) and Ureaplasma urealyticum (serovars 2, 4, 5, 7–13). While frequently thought to be a commensal, Ureaplasma spp. has been found to be the most frequently identified infectious organism associated with preterm delivery. The mechanisms it uses to escape recognition by the host immune system and establish long term chronic infections in the host are unknown. However, association of infection with pregnancy and preterm birth, which have lower immune response are well known and its infection of and induction of preterm birth leads to short and long term sequel. Objectives of the study Using a model of experimental infection, this thesis sought to investigate differences be-tween systemic Ureaplasma infection in mid-second trimester equivalent and early third trimester equivalent, and relate these differences to the stage of development of the com-plement system in preterm lambs. These studies required the development of a new assay to measure complement function in sheep. The ability of the infecting strain of Ureaplas-ma to adapt to the sheep immune system was also investigated, examined at varying lengths of infection. These studies required the use of a new in vivo catheterisation method to establish the kinetics of early experimental intrauterine Ureaplasma infection and to re-cover Ureaplasma from the amniotic fluid by amniocentesis at various times during chron-ic infection. Emerging resistance to sheep complement was investigated in these strains and related to coincident alterations in the major surface antigen (multiple banded antigen; MBA) and alterations in the whole genome sequence. These studies required the charac-terisation of new monoclonal antibodies that recognise the MBA and establishment of a synthetic MBA expressed in E.coli to aid in reagent characterisation. Materials and Methods: Different erythrocyte sources and sensitising antibodies were utilised to establish the guin-ea pig erythrocyte as the best target for measuring the 50% haemolytic activity in fetal and adult sheep sera. Flow cytometry methods were also used to establish endogenous anti-erythrocyte antibodies in adult, but not fetal sheep, revealing a failure of maternal IgG transfer across the placenta in contrast to humans. A bactericidal assay for the decrease in surviving Ureaplasma following incubation with sheep sera was utilised and modified conditions revealed the rate of killing and calcium-dependence of Ureaplasma killing for both fetal and adult sera. Experimental infection of singleton pregnant ewes by catheter or ultrasound guided needle, followed by caesarean delivery at either 94 or 125 days gestation (term=150 days) was central to all of the studies. Over 3 years, different infection duration (from 5 days to 6 weeks) and gestational age at infection (from 70 days to 116 days gesta-tional age) were investigated in this model. Western blot analysis was also a central meth-od for both examining the antibody response of foetus and ewe to Ureaplasma as well as examination of the size and number of MBA isoforms in evolving strains during chronic infection. The use of genomic analysis software Geneious (Biomatters ltd., New Zealand) was also utilised to compare the genomic sequences of Ureaplasma strains recovered by amniocentesis during chronic infection relative to the original infecting strain to determine number and site of genetic alterations with evolving serum resistance. Only the repeat re-gion of the MBA gene required investigation by PCR and traditional Sanger sequencing, due to limitations of Illumina sequencing methods and repeats greater than 150 bp. Results: The 50% complement haemolytic activity of preterm sheep foetuses was very poor at 95 day gestation and improved by 125 day gestation, but was still much lower than adult sera. This was reflected in both in vivo bacteraemia during experimental infection and in vitro examining Ureaplasma-cidal activity of sera. A direct correlation (R2=0.30; p<0.05) was found between haemolytic activity of sera and capacity to kill Ureaplasma in vitro. The strain utilised for experimental infection (HPA5) has a single low mass isoform of MBA consisting of 17 PAGKEQ repeats in the C-terminus. Following 5-7 days infection two of six of the infected animals began to show emergence of a second larger MBA isoform. The number and size of MBA isoforms continued to increase at 3 and 5 weeks, until recov-ered strains appeared to solely consist of strains with much larger MBA isoforms (72->120 k Da). The underlying mechanisms of increased MBA mass was found to be increasing number of PAGKEQ repeats from 17 to >200 repeats. Genomic analysis of recovered strains identified conserved single nucleotide polymorphisms in the two genes encoding the ammonium ion transport, but otherwise very few alterations were observed and no ob-vious candidate to explain increased serum resistance (other than increased MBA mass) were observed. For the most part, alterations occurred in polyA, polyT and polyAT inter-genic regions. Despite the apparent correlation between increasing complement resistance of recovered strains and increasing MBA number of repeats, transposon delivery and ex-pression of the MBA gene from a resistant recovered strain and the serum-sensitive origi-nal HPA5 strain did not transfer serum resistance in one experiment. Conclusions: Ureaplasma can change its surface epitopes continuously however, the ex-pected phase variation loss of MBA expression with development of anti-MBA antibodies was not observed. A strong selection for increased MBA mass was apparent with longer infections and this was coincident with evolution of serum resistance (which increased steadily after 1 week infection to high serum resistance after 5 weeks infection). The de-velopment of the complement system was directly related to the detection of Ureaplasma in the circulation of infected lambs, but even 6 weeks of chronic persistent Ureaplasma infection was found to induce an inconsistent and low antibody response, and only in the later gestational age foetuses. While increased MBA size appears to be coincident with evolved serum resistance, it must require either loss of the original MBA isoform (domi-nant serum susceptibility determinant) or other less obvious alterations in the genome of Ureaplasma.
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Explaining risk for suicide-related behaviour in adolescent offspring of mothers with depressionHammerton, Gemma January 2015 (has links)
Background: There is evidence to suggest that maternal depression is associated with suicide-related behaviour in offspring; however pathways contributing to risk remain unclear. The aim of this thesis was to investigate mechanisms of the association between maternal depression and offspring suicidal ideation and attempt in a general population sample. Methods: Data were utilised from a population-based birth cohort, the Avon Longitudinal Study of Parents and Children. Maternal depression symptoms were assessed on 10 occasions from pregnancy to child age 11 years. Offspring suicide-related behaviour was assessed at age 16 years. Latent class growth analysis was used to derive trajectories of maternal depression symptoms. Pathways mediating risk between maternal depression and offspring suicide-related behaviour were then examined using structural equation modelling. Results: Five distinct classes of maternal depression symptoms were identified (minimal, mild, increasing, sub-threshold, chronic-severe). Compared to offspring of mothers with minimal symptoms, the greatest risk of suicidal ideation was found for offspring of mothers with chronic-severe symptoms [OR 3.04 (95% CI 2.19, 4.21)], with evidence for smaller increases in risk for offspring of mothers with sub-threshold, increasing and mild symptoms. The pattern of findings was similar when examining risk for offspring suicide attempt. The majority of the association between maternal chronic-severe depression and offspring suicidal ideation was explained through maternal suicide attempt and offspring psychopathology. However, there was also evidence for indirect effects via both the parent-child relationship and peer victimisation. Conclusion: Findings from this thesis highlight that risk for suicide-related behaviour should be considered in offspring of mothers with sustained depression symptoms, even when symptoms are below clinical levels. Suicide prevention efforts in offspring of depressed mothers should be targeted at offspring with psychopathology and offspring whose mothers have made a suicide attempt. Interventions aimed at improving the parent-child relationship, or reducing peer victimisation may also be beneficial.
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An investigation of maternal iodine deficiency in the Scottish pregnant populationBannon, Denise Marie January 2014 (has links)
The thyroid gland utilises iodine for the production of the thyroid hormones thyroxine (T4) and triiodothyronine (T3). During pregnancy demand for iodine increases as the need for maternal T4 increases. A lack of iodine leading to hypothyroidism may be associated with cretinism, mental retardation and neurological and thyroid damage. Maternal hypothyroidism is known to be associated with a lower IQ in offspring. In 2002, a study of 400 pregnant women in Tayside demonstrated a deficiency of iodine intake in 40 % of women. The aim of the current study was to establish the trend in iodine status of the pregnant population over a ten year period, examining the factors in the monitoring of iodine and thyroid hormone levels; and the causes and strategies for correction of iodine deficiency during pregnancy. The ranges and distributions of several thyroid biomarkers were established and the relationships between them and between iodine deficiency and specific adverse pregnancy outcomes were explored. A dietary questionnaire was used to collect information on diet, supplement intake and frequency of consumption of different food types. Retrospective study: Urine and matching blood samples collected between 39 and 112 days of gestation from 3500 women and stored frozen for 10 years were analysed for iodine and thyroid hormone levels. Median urinary iodine excretion (UIE) level in 3326 women with normal pregnancy outcome was 107.00 μg/l: significantly below the WHO recommended median for pregnancy of 150.00 μg/l. Just over 65.0 % of women were categorised as having insufficient dietary iodine intake. These results confirm and extend the findings of the 2002 Dundee study. UIE levels adjusted for creatinine (UCr) to correct for urine concentration variation were also investigated. A matching serum sample was available for thyroid hormone analysis in 3240 (97.0 %) of the urine samples with iodine measurements. Median concentrations of each marker in the retrospective normal pregnancy outcome group were: 1.36 μU/ml (TSH), 13.48 μg/dl (T4), 15.05 pmol/l (fT4), 2.17 ng/ml (T3), 6.13 pmol/l (fT3) and 14.21ng/ml (Tg). Linear regression analysis in the normal pregnancy outcome group showed that geographical area was a significant predictor (p < 0.0001) of UIE and UIE/UCr levels and all 6 thyroid markers. Maternal age was the only other significant predictor of UIE levels. Other significant associations were for UIE/UCr: BMI and maternal age; for TSH: BMI, UIE/UCr, ethnicity and hCG; for T4: maternal age and TSH; for fT4: parity, smoking status and TSH; for T3: BMI, maternal age, parity and TSH; for fT3: BMI and TSH, and for Tg: smoking and TSH. ANOVA testing showed that women who smoked had significantly lower fT4 and Tg (p < 0.0001) than non-smokers. Women from Southeast Asia had lower UIE/UCr and TSH (p = 0.04) and higher T4 and T3 compared with Caucasian women (p < 0.0001). Women in Glasgow tended to have higher UIE, T4 and T3 and lower TSH (p < 0.0001) compared to other geographical areas (p < 0.0001). A subset of 971 serum samples from pregnancies with adverse outcome including pre-eclampsia, small for gestation, extreme or moderate preterm delivery, or a still birth was also available for analysis. Binary Logistic Regression showed that for UIE/UCr, TSH, BMI smoking status and maternal age, the only statistically significant variable was smoking which was associated with a lower incidence of pre-eclampsia and a higher incidence of low birth weight. Prospective study: Urinary iodine excretion (UIE) levels were measured in 1106 pregnant women recruited prospectively. The median UIE value was 81.40 μg/l; - lower than the WHO recommended UIE level of 150.00 μg/l, and lower than the median found in the retrospective study group of 107.00 μg/l. Just over 80.0 % of pregnant women were categorised as having insufficient dietary iodine intake according to WHO criteria. These results point to a decline in iodine intake over a 10 year period. UCr measurements showed that 16.8% of samples had levels below the minimum WHO defined limit of 30 mg/dl. The median TSH concentration value in the matching serum samples was 1.25 μU/ml. Maternal TSH levels correlated positively with newborn TSH levels in patients for whom data was available (p < 0.0001). The median value of fT4 within the prospective pregnancy group was 11.41 pmol/l. A subset of 145 serum samples from the prospective pregnancy group selected using UIE levels as a cut-off parameter had a median Tg value of 12.30 ng/ml. Seventy one percent of participants completed a questionnaire on diet. Sixty eight percent were unaware that iodine was important in their diet during pregnancy and had a lower median UIE (79.87 μg/l) compared to those who were aware of the importance of iodine (86.23 μg/l) although this was not statistically significant. Using UIE, UIE/UCr, nTSH, mTSH, fT4, and Tg in turn as the dependent variable in a general linear regression model with up to 15 different predictors (including intake of fish, meat, yoghurt, cheese, milk, cereals, bread, vitamin supplements, iodinated salt usage and maternal age, smoking status, geographic area and the other biomarkers tested) showed no dietary factors and only geographic area and smoking status as significant predictors for UIE. When UIE/UCr was used as the dependent variable, significant associations were maternal age, and intake of bread, cheese, cereals, and iodine supplements. The UIE/UCr ratio gave more significant associations than UIE alone. For nTSH significant predictors were maternal TSH, geographic area and maternal age. For mTSH significant predictors were smoking status and fT4. For fT4, significant predictors were geographic area, TSH and smoking status. For Birth weight, the only significant predictor was smoking status. For Tg, the only significant predictor was UIE/UCr. Ninety two (11.24 %) participants reported that they were aware of the availability of iodised salt but only 11 (1.22 %) women used it. Drinking water samples were collected from 21 sites across the West of Scotland. Only one water sample from 21 collected had an iodine concentration > 10 μg/l. Conclusion: In summary this study has shown a significant trend of decreasing iodine intake in Scottish pregnant women over the last 10 years.
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Prevention of pneumonia after stroke : the effect of metoclopramide on aspiration and pneumonia in stroke patients fed via nasogastric tubesWarusevitane, Anushka January 2015 (has links)
Introduction: Pneumonia contributes significantly to the morbidity and mortality in stroke patients, especially those fed via nasogastric tubes. Methods: This project was conducted in two steps; 1. A randomised controlled trial: The efficacy of prokinetic agent metoclopramide was tested in a double-blind randomised controlled trial. Acute stroke patients with no pneumonia needing nasogastric feeds were randomized to 10 mg metoclopramide or placebo three times daily via the nasogastric tube for 21 days or until feeds discontinued. Participants were examined daily for clinical evidence of pneumonia. 2. A secondary analysis of data collected for the diagnosis of pneumonia. This was performed to identify early diagnostic markers of post-stroke pneumonia. Results: 1) For the MAPS study 60 patients (mean age 78 years, mean NIHSS 19) were randomized, 30 in each group. Pneumonia was diagnosed in 26/30 and 08/30 in placebo and treatment group respectively (p < 0.001). 2) Signs and symptoms of 47 radiologically confirmed pneumonia revealed that hypoxia, tachypnoea and inspiratory crackles were the most consistent signs in early pneumonia and pyrexia, cough, and purulent sputum were less commonly observed. CRP of 40 mg/l had the best predictive value for early diagnosis of post-stroke pneumonia. Conclusion: Treatment with metoclopramide treatment was associated with a significant reduction of aspiration and pneumonia. However, the incidence of pneumonia in the control gourp was very high and may have led to a false positive result. The findings of this study should therefore be confirmed in a larger study. A raised CRP of 40 mg/l or above was a senditive and specific diagnostic marker for post-stoke pneumonia.
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Activation of endothelial cells and its potential involvement in blood-brain barrier damage in cerebral malaria : an in vitro studyMohd Nasir, Mohd Hamzah January 2015 (has links)
One of the severe complications of a Plasmodium falciparum infection is cerebral malaria (CM). CM is characterised by the accumulation of mature infected red blood cells (RBC) in the brain microvasculature. One of the consistent detrimental effects of sequestration is the breakdown of the blood-brain barrier (BBB), often with a fatal outcome in children in endemic areas. This study investigates the mechanisms underlying BBB breakdown secondary to sequestration, using immortalised human brain microvascular endothelial cells (tHBEC) as an in-vitro model of BBB and ITG-strain Plasmodium falciparum. First, the tHBEC monolayer was co-cultured with Plasmodium falciparum infected red blood cell (PRBC) or uninfected red blood cells (uRBC) control for 20 hours and the supernatant was recovered for subsequent analysis. The co-culture supernatants showed upregulation of inflammatory mediators (MCP-1 and IL-8) and a member of metalloproteases (ADAMTS-1, ADAMTS-4, MMP-2 and MMP-9) in the PRBC-tHBEC co-culture supernatants. The PRBC-tHBEC co-culture supernatants induced loss of endothelial cell monolayer integrity, represented by real time reduction in the transendothelial electrical resistance, measured using Electrical Cell-Substrate Impedance Sensing (ECIS™). The same supernatants also increased the permeability of tHBEC monolayer to the fluorescently labelled 40 kDa dextran showing leakage across the tHBEC monolayer. Interestingly, the loss of barrier function of tHBEC monolayer is partially inhibited by the addition of protease inhibitors GM6001 and rhTIMP-3. Prolonged exposure to PRBC-tHBEC co-culture supernatants reduced the level of vinculin. This study demonstrates that the interactions between PRBC and tHBEC induces activation of tHBEC and the release of proteases that contribute to BBB breakdown in CM, and could be a potential drug target for adjunct therapy in CM.
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Manipulating T-lymphocyte homing and activation for cancer immunotherapyWehenkel, Sophie January 2015 (has links)
The immune system, and in particular CD8+ T cells, have the potential to eliminate tumours and novel immunotherapies are giving encouraging results for cancer patients. This thesis focuses on the improvement of one such therapy, adoptive T cell therapy. The aim of this thesis was to genetically modify human CD8+ T cells to enhance their anti-tumour potential for adoptive T cell therapy. One approach was to mutate the SH2 domain containing protein tyrosine phosphatase (SHP-1) gene to reduce T cell checkpoint inhibition. A second approach was to express a shedding-resistant form of L-selectin in T cells to promote T cell homing. In this thesis, the rapid shedding of L-selectin within minutes after TCR stimulation was shown to be ADAM17 dependent. Furthermore, new data indicated a second proteolytic cleavage which is γ-secretase dependent. The shedding-resistant L-selectin (ΔM-N) was shown to resist proteolysis by both ADAM17 and γ-secretase. Previous work by our group and others has shown that the loss of SHP-1 leads to the enhanced entrance of T cells into proliferation and gives better protection against tumour growth in mice. To study the effect of SHP-1 loss in human CD8+ T cells, SHP-1 deficient tumour-specific T cells were generated by lentiviral delivery of a pair of SHP-1 specific zinc finger nucleases in conjunction with the Mel TCR. Populations of melanoma-specific CD8+ T cells containing a small fraction (< 8 %) of SHP-1 mutant cells showed no enhanced Mel526 target cell killing in vitro or in vivo in Mel526 xenograft bearing NSG mice. However, there was some suggestion of enhanced survival and/or proliferation in vitro of melanoma-specific CD8+ T cells containing a population of SHP-1 CD8+ mutant cells. Overall the proof of principle of gene-editing SHP-1 in T cell lines and primary CD8+ T cells was demonstrated which supports further exploitation of this approach for testing in adoptive T cell therapy strategies.
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