Contexto: Pacientes com tireoidite autoimune crônica com anticorpos de peroxidase tireoideana (Anti-TPO) podem progredir para hipotireoidismo subclínico e clínico. Estudos anteriores mostraram uma redução no anti-TPO em pacientes com hipotireoidismo que receberam tratamento de reposição de LT4 e suplementação de selênio. Objetivos: Avaliar se a selenometionina (SeMet) reduz o anti-TPO em pacientes anti-TPO positivos eutireoideos tratados com LT4 e melhora a ecogenecidade da tireoide em comparação com grupo de pacientes tratados com placebo. Desenho: Estudo duplo-cego aleatório controlado com placebo. Pacientes e métodos: Um total de 55 pacientes consecutivos com TCA (50 mulheres, 5 homens, idade mediana de 48 anos variando de 20 a 58), 4 tabagistas, 4 anos desde o diagnóstico da doença (mediana), com TSH normal ou levemente elevado, T4L dentro dos níveis normais, anti-TPO maior que 100 U/ml foram aleatoriamente selecionados para receber uma dose diária de 200 ?g de selenometionina (grupo SeMet; n = 28) ou placebo (grupo P; n = 27) por 3 meses. Anticorpos da tireoperoxidase e tireoglobulina (TPO-Ab; TG-Ab), TSH, FT4, T3, T4, proteína C-reativa (PCR), citocinas (IL6, IL10, TNF), glicose sanguínea em jejum, calcitonina, selênio plasmático, concentração de iodo na urina, atividade da peroxidase de glutationa 1 em eritrócitos (GPx1) foram dosados no basal, após 3 e 6 meses de acompanhamento. Polimorfismo do GPx1-Pro198Leu foi avaliado no basal. Foi efetuado ultrassom de tireoide (US) em cada ponto de acompanhamento. Ecogenecidade do tecido foi caracterizada por análise histográfica computadorizada em escala de cinza e expressa como índice de ecogenecidade (EI). A relação entre concentração de Selênio e atividade GPx1 nos eritrócitos foi analisada para cada genótipo. O IE e associações de variáveis clínicas também foram avaliadas. Resultados: Não houve diferenças nas características iniciais (basais) entre o grupo SeMet e P. Selênio plasmático e atividade GPx1 aumentaram no grupo SeMet mas não variaram no grupo P durante a suplementação de SeMet. Anti-TPO, anti-TG, TSH e hormônios tireoidianos não variaram significativamente no grupo P. Anti-TPO no grupo SeMet era de 1009 (176- >3000) no basal, 958 (161- > 3000) aos 3 meses e 768 (65-2821) U/ml aos 6 meses. Neste grupo, as variações em relação ao basal foram de -5% aos 3 meses e -24% aos 6 meses, respectivamente. No grupo P, as mudanças em relação ao basal foram de 1206 (154- >3000), 1404 (231- >3000), 1430 (140- >3000 U/ml), respectivamente (valores médios e limítrofes); +16% aos 3 meses e +18% aos 6 meses, respectivamente. Níveis de TSH, no grupo SeMet, foram de 1,7 (0,8 - 2,5) no basal, 3,0 (1,1 - 6,3) aos 3 meses e 3,2 (1,1 - 6,5) ?U/mL aos 6 meses, no grupo P, os níveis de TSH foram de 1,7 (0,8 - 2,5) no basal, 2,2 (0,6 - 6,8) e 2,5 (0,9 - 5,5) ?U/mL, respectivamente (valores médios e limítrofes). Valores médios da proteína C-reativa foram inferiores a 10mg/L nos dois grupos. O percentual dos genótipos no grupo SeMet eram de 7,1%, 64,3% e 28,6% para Leu/Leu, Pro/Leu e Pro/Pro (o genótipo mais frequente), respectivamente; no grupo P, a distribuição foi 0,0%, 51,9% e 48,1% para Leu/Leu, Pro/Leu e Pro/Pro, respectivamente, comparado com controles normais (11,4%, 39,2% e 49,4% Leu/Leu, Pro/Leu e Pro/Pro respectivamente). O IE exibiu tendência a uma diferença significativa indo de 1,2 no basal para 1,0 aos 3 meses e 1,1 aos 6 meses para o grupo SeMet, respectivamente, enquanto que permaneceu constante (1,2 no basal, 1,2 aos 3 meses e 1,2 aos 6 meses) para o grupo P, respectivamente. Após o período de suplementação, o coeficiente de correlação r = 0,95 (p < 0,001) para Pro/Pro e a tendência foi a mesma que o basal para o grupo Pro/Leu. No grupo SeMet, o IE correlacionou-se positivamente com a velocidade sistólica de pico nas artérias inferiores da tireoide no basal (r = 0,5, p = 0,008) e após o período de suplementação (r = 0,46; p = 0,025). Anti-TG correlacionou-se com valores do fator de necrose tumoral médios no grupo placebo (r = 0,46; p = 0,015). Conclusão: A suplementação por 3 meses aumentou os marcadores do status de selênio. SeMet parece ser eficaz em reduzir a ecogenecidade da tireoide e em reduzir o anti-TPO (porém não o anti-TG) após 3 meses de intervenção, mas não influencia o TSH ou os hormônios tireoideanos / Context: Autoimmune chronic thyroiditis (ACT) euthyroid subjects with positive thyroid peroxidase antibodies (TPO-Ab) may progress to subclinical and overt autoimmune hypothyroidism. Previous studies have shown a decrease in TPO-Ab in hypothyroid patients receiving LT4 replacement therapy plus selenium supplementation. Objectives: To evaluate in euthyroid TPOAb-positive LT4-treated subjects whether selenometionine (SeMet) decreases TPO-Ab and improves thyroid ecogenicity in comparison with placebo. Design: Randomized, placebo-controlled, double-blind study. Patients and methods: A total of 55 consecutive patients with ACT (50 F, 5 M, age median: 48, range: 20-58 years), 4 smokers, duration of disease (median) 4 years, normal or slightly elevated TSH and FT4 within the normal range, TPO-Ab >= 100 U/mL were randomized to receive 200 ?g selenometionine daily ((group SeMet; n = 28) or placebo (group P; n = 27) for 3 months. Thyroperoxidase and thyroglobulin autoantibodies (TPO-Ab; TG-Ab), TSH, FT4, T3, T4, C-reactive protein (CRP), cytokines (IL6, IL10, TNF), fasting blood glucose, calcitonin, plasma selenium, urine iodine concentrations, activity of glutathione peroxidase 1 in erythrocytes (GPx1) were estimated at baseline, after 3 and 6 months of follow-up; GPx1-Pro198Leu polymorphism was assessed at baseline. Thyroid ultrasound (US) was performed at each follow-up point. Tissue ecogenicity was characterized by computerized grey-scale histographic analysis and expressed as ecogenicity index (EI). The relationship between Se concentration and GPx1 erytrocyte activity was analysed for each genotype group. EI and clinical variables associations were also evaluated. Results: There were no differences in baseline characteristics between the SeMet group and the P group. During SeMet supplementation, plasma Se and GPx1 activity did not change in the P group, but increased in the SeMet group. TPO-Ab, anti-TG, TSH and thyroid hormones did not change significantly in group P. TPO-Ab in the SeMet group were 1009 (176- >3000) at baseline, 958 (161- >3000) at 3 months and 768 (65-2821) U/mL at 6 months. In this group change from baseline were -5 at 3 months and -24% at 6 months, respectively. In the P group change from baseline were 1206 (154- >3000), 1404 (231- >3000) and 1430 (140- >3000) U/mL, respectively (mean values with range); from baseline were +16 at 3 months and +18% at 6 months, respectively. TSH in the SeMet group were 1.7 (0·8-2·5) at baseline, 3·0 (1·1-6·3) at 3 months and 3.2 (1,1-6,5) uU/mL at 6 months; in the P group were 1·7 (0·8-2·4), 2·2 (0·6-6·8) and 2.5 (0.9-5.5) ?U/mL, respectively (mean values with range). C-reative protein mean level was <10 mg/L in both groups. Genotype proportions in the SeMet group were 7.1, 64.3, and 28,6% for Leu/Leu, Pro/Leu and Pro/Pro (the wild-type genotype), respectively; in the P group were 0.0, 51.9 and 48.1 for Leu/Leu, Pro/Leu and Pro/Pro, respectively compared with normal controls (11.4, 39.2 and 49.4%, Leu/Leu, Pro/Leu and Pro/Pro, respectively). EI exhibited a tendency towards a significant difference from 1.2 at baseline to 1.0 at 3 months and 1.1 at 6 months for the SeMet group, respectively and remained the same (1.2 at baseline, 1.2 at 3 months and 1.2 at 6 months) for the P group, respectively. For the SeMet group there was no significant correlation for Pro/Pro and Pro/Leu genotypes at the baseline. After the supplementation period, the correlation coefficient was r = 0.95 (p < 0.001) for Pro/Pro and the trend was the same as baseline for Pro/Leu. In the Semet group EI correlated positively with systolic peak velocity in the inferior thyroid arteries at baseline (r = 0.50; p = 0.008) and after supplementation period (r = 0,46; p = 0,025). Anti-TG correlated with tumor necrosis factor mean values in the Placebo group at baseline (r = 0,46; p = 0,015). Conclusion: Three months selenometionine supplementation increased markers of selenium status. SeMet seems to be effective in reducing thyroid echogenicity and in reducing TPO-Ab (but not TG-Ab) after 3 months of intervention, but does not influence TSH or thyroid hormones

Nos últimos anos, um importante destaque tem sido dado aos linfócitos Th17 para o desenvolvimento e manutenção da inflamação associada à autoimunidade. A esclerose múltipla é uma doença autoimune desmielinizante do SNC, cuja patogênese está associada à resposta do padrão Th17. Evidências têm demonstrado que estas células são submetidas a uma reprogramação metabólica após serem ativadas, sendo essa adequação essencial para sua completa diferenciação e aquisição de funções efetoras. A enzima Piruvato Quinase M2 (PKM2) participa da etapa final da glicólise convertendo fosfoenolpiruvato em piruvato. Estudos recentes demonstraram que a fosforilação de PKM2 a torna capaz de translocar para o núcleo, onde adquire um papel no controle da expressão gênica. Nesse sentido, o objetivo deste estudo foi avaliar o envolvimento da PKM2 na diferenciação de linfócitos Th17, bem como sua participação no desenvolvimento da encefalomielite autoimune experimental (EAE), um modelo animal de esclerose múltipla. Observou-se que durante o processo de diferenciação, os linfócitos Th17 aumentam a expressão gênica de PKM2 bem como a sua forma fosforilada (Y105). De forma interessante, tanto a inibição farmacológica como a deleção gênica da PKM2 especificamente em linfócitos T promoveram uma redução da diferenciação e expansão da subpopulação Th17, que foi associada com diminuição na expressão de moléculas efetoras e fatores de transcrição chave para o estabelecimento do fenótipo Th17. Em um contexto de resposta autoimune, notou-se que PKM2 é superexpressa nos órgãos linfóides periféricos e sistema nervoso central de animais com EAE, sendo correlacionada com o infiltrado de células inflamatórias. Corroborando com os dados in vitro, a deficiência de PKM2 em linfócitos T promoveu redução dos sinais clínicos da EAE, acompanhada de baixa frequência de linfócitos Th17 e menor expressão de moléculas inflamatórias do perfil Th17. Adicionalmente, o tratamento farmacológico com o inibidor da PKM2 atenuou a progressão e gravidade da EAE. Portanto, esses achados implicam um importante papel para PKM2 em doenças autoimunes por regular o desenvolvimento e função de linfócitos Th17. / Over the past few years, an important highlight has been given to Th17 lymphocytes for the development and maintenance of autoimmunity-associated inflammation. Multiple sclerosis is a CNS demyelinating autoimmune disease that is associated to Th17-mediated response. Some evidences have demonstrated that those cells undergo metabolic reprogramming after being activated, which is essential for their complete differentiation and acquisition of effector functions. The enzyme Pyruvate kinase M2 (PKM2) participates at the final step of glycolysis by converting phosphoenolpyruvate into pyruvate. Recent studies have demonstrated that PKM2 phosphorylation allows its translocation into the nucleus, where it plays a role in controlling gene expression. Thus, the aim of this study was to evaluate the involvement of PKM2 in Th17 lymphocytes differentiation, as well as its role in experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis. It was perceived that during differentiation process, Th17 lymphocytes increase PKM2 gene expression, and also its phosphorylated form (Y105). Interestingly, both pharmacological inhibition and T-lymphocyte-specific PKM2 gene deletion promoted a reduction in differentiation and expansion of Th17 subpopulation, being associated to diminished expression of effector molecules and key transcription factors for the establishment of Th17 phenotype. In the context of an autoimmune response, it was noticed that PKM2 is overexpressed in peripheral lymphoid organs and central nervous system of EAE-bearing mice, which was correlated with the inflammatory cell infiltration. Corroborating with in vitro data, the deficiency of PKM2 in T lymphocytes led to a reduction of EAE clinical score along with low Th17 frequency and diminished expression of Th17-related inflammatory molecules. Additionally, pharmacological treatment with the PKM2 inhibitor attenuated EAE progression and severity. Therefore, these findings imply an important role for PKM2 in autoimmune diseases by regulating the development and function of Th17 lymphocytes.

Statins are cholesterol-lowering medications with immunologic properties. To assess the role of statins on incident immune-mediated conditions, a modified case-cohort study was performed using administrative databases from the Midwest Veterans Administration (VA) region. A comparison sub-cohort was formed by randomly sampling 10,000 subjects with medical and pharmacy benefits during fiscal year (FY) 2002. Cases were identified by inpatient or outpatient medical claims using International Classification of Disease, Ninth Revision (ICD-9) codes between FY 2003-2004. All subjects needed at least one year of medical claims and at least one pharmacy claim. The incident cases (n=28,642) included non-mutually exclusive groups of immune-mediated (n=2,327), infectious (n=8,221), and non-immunologic (n=10,730) diagnoses. Demographic and medical variables were obtained from FY 2001-2004, and pharmacologic data from FY 2002-2004. Cox proportional hazards regression modeling was used to estimate hazard ratios for the current statin use (within the last 180 days) and former statin use, compared to non-users, including time-dependant variables for demographic factors, comorbidity as measured by Elixhauser and Chronic Disease Score variables, medications, and visit rates after initiating statins. Current statin use was associated with decreased diagnoses rates of psoriasis; rheumatoid arthritis; inflammatory bowel diseases, including ulcerative colitis and Crohn disease; diffuse connective tissue diseases, including systemic lupus erythematosus; ankylosing spondylitis; bacterial pneumonia; urinary tract infection; cellulitis; sepsis; candidiasis; osteomyelitis; and tuberculosis. Former statin use was also associated with increased rates of polymyalgia rheumatica, sepsis, and osteomyelitis. Statin use was not associated with other spondylitis, multiple sclerosis, thyroiditis, sarcoidosis, temporal arteritis, influenza, shingles, histoplasmosis, or pyelonephritis. Although current statin use appeared protective for some study conditions, selection bias, misclassification, healthy user effects, adherence bias, confounding by indication, and surveillance bias were considered as possible explanations of the study findings.

Proper immune function is indispensable, as failure to mount an immune response against a pathogen can lead to serious complications or even death. T cells act by enhancing the activation of phagocytic cells as well as the activation of B cells. Their widespread influence on an immune response makes optimal T cell activation vital. Maximal T cell proliferation and survival is accomplished by stimulation with antigen, a costimulatory signal, and an adjuvant. However, excessive T cell activation can lead to chronic B cell activation and the production of autoantibodies, a hallmark of autoimmune disease. In this thesis, optimal T cell stimulation was studied using an in vivo adoptive transfer model. Results showed that antigen stimulation of T cells along with ligation of the costimulatory molecule OX40 led to an accumulation of antigen-specific cells. OX40 ligation allowed the antigen specific cells to proceed through more cell cycles than cells stimulated with antigen alone. The addition of the adjuvant lipopolysaceharide (LPS) to this system allowed for increased cell survival. However, the continual presence of an adjuvant may also have injurious effects. This was highlighted with the appearance of "Toxic Oil Syndrome" (TOS) in which an adulterated rapeseed oil, an oil with known adjuvant activity, was sold for human consumption. People developed an autoimmune condition characterized by polyclonal B cell activation and autoantibody production. A genetic predisposition was implicated with TOS and was further investigated in this thesis. Although the A. SW mouse has the genetically susceptible genotype, these mice did not develop TOS following exposure to "toxic oil" indicating that other factors may be important in TOS susceptibility. Extending the techniques used in these studies and applying them to the canine immune system was the final topic investigated in this series of studies. Understanding immune pathways of the mammalian immune system is particularly important for comparative studies when dogs are used as models to investigate human immune system disorders. These studies combined will allow for a better understanding of the balance between an optimal immune response and an imbalance leading to hypersensitivity or immunosuppression, as well as interspecies relationships. / Graduation date: 2002

The organic mercury compound ethylmercurithiosalicylate (thimerosal), an antiseptic and a preservative, has recently raised public health concern due to its presence in vaccines globally. Thimerosal dissociates in the body to thiosalicylate and ethyl mercury (EtHg), which is partly converted to inorganic mercuric mercury (Hg2+). The immunosuppressive, immunostimulatory, and de novo autoimmunogen effect of thimerosal in mice, as well as the accelerating/aggravating effect on spontaneous systemic autoimmunity including dose-response aspects were the subject of this thesis. Thimerosal perorally (590 μg Hg/kg body weight (bw)/day) to genetically susceptible (H-2s) mice caused immunosuppression during the first week with reduction of the total number of splenocytes, T- and B-cells. The suppression lasted 2 weeks for CD4+ cells, but was superseded by a strong immunostimulation/proliferation including T- as well as B-cells, and polyclonal B-cell activation (PBA). Antinuclear antibodies targeting the 34-kDa nucleolar protein fibrillarin (AFA) appeared after 10 days, followed by renal mesangial and systemic vessel wall immune-complex (IC) deposits. The Lowest Observed Adverse Effect Level (LOAEL) was in the order AFA = glomerular and splenic vessel wall deposits &lt; hyperimmunoglobulinemia &lt; PBA. The LOAEL for AFA was 118 μg Hg/kg bw/day. The LOAEL for the different parameters of this thimerosal-induced systemic autoimmune condition (HgIA) was 3-11-fold higher compared with HgIA induced by HgCl2. The thimerosal-induced HgIA shared with HgCl2 a significant dose-response relationship, and requirement for: T-cells, the costimulatory factor CD28, the IFN-γ/IFN-γ-receptor pathway,but not IL-4. The mRNA expression in lymph nodes of IL-2, IFN-γ, IL-4, and IL-15 was significantly increased but not delayed compared with HgCl2. Treatment with the ubiquitous organic Hg compound methyl Hg using equimolar doses of Hg (533 μg Hg/kg bw/day) caused a transient immunosuppression, followed by a weak immunostimulation and AFA. The IgG AFA isotypes induced by the organic Hg compounds MeHg and EtHg were stable and dominated by a Th1-like pattern over a broad time- and dose range. Treatment with inorganic HgCl2 caused a dose- and time-dependent pattern of IgG AFA isotypes. Low doses favored a Th1-like pattern, a high dose a balanced or Th2-like pattern. Middle-range doses showed initially a Th1-like pattern which gradually evolved into a balanced or Th2-like pattern. The qualitative difference in IgG AFA isotypes between organic and inorganic Hg may be due to differences in activation and/or suppression of T-helper cell subsets or factors influencing the Th1/Th2-function. Speciation of the renal Hg2+ concentration and comparison with the threshold dose for induction of AFA by HgCl2 showed that even with the lowest doses of thimerosal and MeHg used in this thesis, the AFA response might from a dose threshold point of view have been caused by conversion of the organic Hg species to Hg2+. Primary treatment with inorganic Hg (HgCl2) accelerates/aggravates murine systemic autoimmunity, both spontaneous (genetic) and induced by other means. This capacity was assessed for thimerosal over a broad dose range using the (NZB X NZW)F1 hybrid mouse model. Significantly increased antinuclear antibodies (ANA) was seen after 4-7 weeks treatment (LOAEL 147 μg Hg/kg bw/day), and the response was dose-dependent up to 13 weeks. Renal mesangial and systemic vessel walls deposits similar to those in de novo HgIA were present after 7 weeks treatment. Twenty-two to 25 weeks treatment with thimerosal caused, in a dose-dependent fashion (LOAEL 295 μg Hg/kg bw/day), relocalization of the spontaneously developing glomerular IC deposits from the capillary vessel walls to the mesangium, which attenuated histological kidney damage and proteinuria, and increased survival. Thimerosal caused systemic vessel wall IC-deposits over a broad dose range: the Low Observed Adverse Effect Level (LOAEL) for renal and splenic vessel wall IC deposits was 18 and 9 μg Hg/kg bw/day, respectively. The No Observed Adverse Effect Level (NOAEL) could not be determined for the latter, since deposits were present even with the lowest dose used. Thimerosal causes in genetically susceptible mice an initial, transient immunosuppression which is superseded by a strong immunostimulation and systemic autoimmunity, sharing many characteristics with the HgIA induced by inorganic HgCl2. The IgG AFA isotype pattern is however qualitatively different, and the threshold dose substantially higher. In contrast, long-term treatment with thimerosal induces systemic vessel wall IC-deposits also using doses below those needed to induce HgIA de novo in H-2s mice.

Multiple Sclerosis (MS) is the most common demyelinating condition of the central nervous system (CNS), resulting in paralysis and death. The etiology of MS is unknown. However, genetics, exposure to a pathogen, psychological stress and gender are all implicated in the onset and progression of the disease. An animal model of MS, Theiler’s virus (TMEV) infection, causes a biphasic disease. An early CNS viral infection, if allowed to persist within the CNS, is followed by a chronic CNS autoimmune demyelinating condition that is similar to MS. The development of Theiler’s Virus Induced Demyelination (TVID) is under genetic control: SJL mice are highly susceptible to viral persistence and TVID while CBA mice have an intermediate susceptibility. Chronic restraint stress (RST) administered during the first four weeks of TMEV infection influenced the subsequent development of TVID differentially across strain and sex of mice. TVID was exacerbated by RST in male and female SJL mice, but in the CBA strain, TVID was alleviated by RST in male mice only. This pattern of results in SJL and CBA mice could be seen in the chronic phase of TVID on multiple dependent measures: body weights, behavioral signs of the chronic phase, rotarod performance (an automated measure of motor abilities), and inflammation, demyelination, and axonal loss within the spinal cord. The exacerbation of TVID in SJL mice provides some of the first experimental evidence that coincides with reports of stress precipitating the onset of MS in human patients. The sex dependent alleviation of TVID in CBA mice illustrates the complex interaction between genetic predisposition, gender, stress, and exposure to a pathogen that has been proposed for the development of MS.

Neural Tube Defects (NTDs) are a group of common congenital malformations that result from incomplete neural tube closure leading to abnormalities of the brain and/or spinal cord. Unfortunately, their etiology remains unknown, probably due to complex multifactorial interactions. The protective effect of dietary folates in preventing NTDs is well known, but this beneficial effect is limited to the 60 to 70% of cases; leaving 30% of the population without any known option for improving pregnancy outcomes. The mechanism by which folates rescue NTD-affected embryos is poorly understood, but the ability of folate supplementation to overcome a significant percentage of NTDs and the critical role of 5-methyltetrahydrofolate in the remethylation of homocysteine (Hcy) to methionine in the placenta suggests that folate binding and/or transport might play a critical role during development. We hypothesized that maternal autoantibodies (AB) targeting placental folate receptor alpha (FRα) are blocking the receptor and limiting the ability of the FRα to bind folates, reducing intraembryonic folate levels. Furthermore, we hypothesized that AB binding to other relevant proteins required for trophoblastic growth and placentation can be involved in activating pathologic inflammatory pathways that can result in suboptimal uptake of nutrients and contribute to an abnormal closure of the neural tube. We developed a high throughput ELISA to evaluate whether mothers experiencing pregnancies complicated with NTDs are more likely to have placental AB to FRα than are mothers experiencing normal pregnancies. We optimized and simplified a protocol for AB elution from placental tissues and determined whether these antibodies were blocking the FRα from binding with available folates. Although anti-FRα IgG antibodies were not associated to the blocking activity in this study, we found that the blocking activity was higher in the placentas from NTD-affected pregnancies compared to controls, that FRα IgM antibodies are most likely the type of antibody produced during gestation that is most relevant to the blocking activity and that it is unlikely that autoimmunity against other developmental proteins associated with NTDs is generating the NTDs. / text

Early Growth Response Genes (EGR) is a family of four transcription factors containing a unique zinc finger domain. EGR-2 and EGR-3 are important for hindbrain development and myelination. These transcription factors are also necessary for lymphocyte function however, the mechanisms are still unclear. Previous findings have shown that EGR-2cKO mice develop lupus-like autoimmune disease with high levels of pro-inflammatory cytokines despite showing normal T and B cell proliferation after mitogenic stimulation. Therefore we established the CD2-EGR-2-/-EGR-3-/- mouse model to explore the phenotype, susceptibility to autoimmune disease and relevant lymphocyte function. We discovered that CD2-EGR-2-/-EGR-3-/- mice developed severe systemic autoimmune disease and expressed high levels of inflammatory cytokines. More importantly we discovered a novel finding that CD2-EGR-2-/-EGR-3-/- T and B cells had impaired cell proliferation after mitogenic stimulation. Further investigations revealed that the molecular mechanism defected in the T cell receptor signalling pathway is due to a dysfunction in Activator Protein-1 (AP-1). AP-1 is a heterodimeric protein composed of AP-1 family members including Jun, Atf and Fos. Our data shows that EGR-2 and EGR-3 directly bind with the Atf family member Batf, which prevents Batf’s inhibitory function on AP-1 activation. This research demonstrates that EGR-2 and EGR-3 intrinsically regulate chronic inflammation and also positively regulate antigen receptor activation. In conclusion EGR-2 and EGR-3 are essential for providing optimal immune responses, whilst limiting inflammatory immunopathology. We propose that this new model could be used for studying autoimmune disease.

No description available.

Thesis (M. Phil.)--University of Hong Kong, 2008. / Also available in print.