A formulação de vacinas efetivas frequentemente requer a adição de adjuvantes capazes de otimizar as respostas imunes humoral e celular. Com o objetivo principal de contribuir para o desenvolvimento de novos adjuvantes, este trabalho foi desenvolvido buscando aprofundar o conhecimento do mecanismo de ação imunoadjuvante de preparações de saponinas de Quillaja brasiliensis e suas formulações em complexos imunoestimulantes do tipo ISCOM. Como a toxicidade das saponinas é um fator crítico para seu uso em preparações vacinais, inicialmente foram realizados ensaios visando comparar a toxicidade in vitro e in vivo de saponinas extraídas de Quillaja brasiliensis com saponinas de ação imunoestimulante reconhecidas, extraídas de Quillaja saponaria (Quil A). O potencial imunoadjuvante das saponinas solúveis de Q. brasiliensis foi avaliado utilizando preparações com dois antígenos: ovalbumina (OVA) e vírus da diarreia viral bovina (BVDV). Numa etapa seguinte, a atividade imunoadjuvante de ISCOMs preparados com saponinas de Q. brasiliensis foram avaliadas em duas vias de administração. O potencial imunomodulador dessas saponinas foi verificado em experimentos de recrutamento celular in vivo e expressão de genes relacionados ao sistema imune. Os resultados mostraram que saponinas de Q. brasiliensis são menos tóxicas que as de Quil A e apresentam atividade adjuvante similar, caracterizada por um perfil Th1/Th2 balanceado. Q. brasiliensis promoveu uma forte resposta imune celular do tipo Th1 caracterizada por uma robusta reação de hipersensibilidade celular tardia (DTH) e pela produção de IFN- e IL-2. A resposta imune induzida pelos ISCOMs produzidos a partir de saponinas de Q. brasiliensis foram superiores às respostas induzidas pelas saponinas solúveis. Os testes in vivo mostraram que as saponinas de Q. brasiliensis promovem um ambiente imunocompetente no local da inoculação e nos linfonodos drenantes. Esse ambiente foi caracterizado pelo intenso influxo celular (neutrófilos, células NK, células dendríticas, linfócitos T e B), além da expressão diferencial de genes relacionados à ativação do sistema imune. Em suma, os resultados mostraram que saponinas de Q. brasiliensis são seguras e seus potencial adjuvante foi equivalente a saponinas com ação imunoadjuvante conhecida de Q. saponaria. / Effective vaccine formulations frequently require addition of adjuvants able to optimize the cellular and humoral immune responses. With the goal to contribute to the development of new classes of adjuvants, this work was developed in order to achieve deep knowledge on the imunoadjuvant mode of action for Quillaja brasiliensis saponins incorporated into immunostimulant complex (ISCOM). The toxicity of saponins is a critical factor for its usage as vaccine preparations. At first, in vivo and in vivo citoxicity assays were carried out to compare to the effects between saponins extracted from Quillaja brasiliensis and the immunostimulant saponins already known from Quillaja saponaria (Quil A). Imunoadjuvant potential of soluble saponins from Q. brasilienis was evaluated using preparations of two antigens: ovoalbumin (OVA) and bovine viral diarrhea (BVD). As a next step, imunoadjuvant activity of ISCOMS prepared with Q. brasiliensis saponins was evaluated using two routes of administration. The immunomodulatory potential of these saponins was tested during in vivo cell recruitment assays and gene expression related to immune system. Our results demonstrated that Q. brasilienis saponins are less toxic than those from Quil A and presenting similar adjuvant activity, characterized by a Th1/Th2 balance profile. Q.brasiliensis induced a strong Th1 cell-mediated immune responses indicated by a robust delayed type hypersensitivity (DTH) as well as IFN-у and IL-2 production. The immune response induced by ISCOMs from Q. brasiliensis saponins was higher than the one induced by soluble saponins. In vivo experiments indicated that saponins from Q. brasiliensis generate an immunocompetent environment at the injection site and draining lymph nodes. This environment was characterized by an intense cell influx (neutrophils, NK cells, dendritic cells, B and T cells) as well as differential gene expression related to immune system activation. In essence, the results showed that saponins from are safe and their adjuvant potential was equivalent to saponins with imunoadjuvant activity of Q. saponaria.

A formulação de vacinas efetivas frequentemente requer a adição de adjuvantes capazes de otimizar as respostas imunes humoral e celular. Com o objetivo principal de contribuir para o desenvolvimento de novos adjuvantes, este trabalho foi desenvolvido buscando aprofundar o conhecimento do mecanismo de ação imunoadjuvante de preparações de saponinas de Quillaja brasiliensis e suas formulações em complexos imunoestimulantes do tipo ISCOM. Como a toxicidade das saponinas é um fator crítico para seu uso em preparações vacinais, inicialmente foram realizados ensaios visando comparar a toxicidade in vitro e in vivo de saponinas extraídas de Quillaja brasiliensis com saponinas de ação imunoestimulante reconhecidas, extraídas de Quillaja saponaria (Quil A). O potencial imunoadjuvante das saponinas solúveis de Q. brasiliensis foi avaliado utilizando preparações com dois antígenos: ovalbumina (OVA) e vírus da diarreia viral bovina (BVDV). Numa etapa seguinte, a atividade imunoadjuvante de ISCOMs preparados com saponinas de Q. brasiliensis foram avaliadas em duas vias de administração. O potencial imunomodulador dessas saponinas foi verificado em experimentos de recrutamento celular in vivo e expressão de genes relacionados ao sistema imune. Os resultados mostraram que saponinas de Q. brasiliensis são menos tóxicas que as de Quil A e apresentam atividade adjuvante similar, caracterizada por um perfil Th1/Th2 balanceado. Q. brasiliensis promoveu uma forte resposta imune celular do tipo Th1 caracterizada por uma robusta reação de hipersensibilidade celular tardia (DTH) e pela produção de IFN- e IL-2. A resposta imune induzida pelos ISCOMs produzidos a partir de saponinas de Q. brasiliensis foram superiores às respostas induzidas pelas saponinas solúveis. Os testes in vivo mostraram que as saponinas de Q. brasiliensis promovem um ambiente imunocompetente no local da inoculação e nos linfonodos drenantes. Esse ambiente foi caracterizado pelo intenso influxo celular (neutrófilos, células NK, células dendríticas, linfócitos T e B), além da expressão diferencial de genes relacionados à ativação do sistema imune. Em suma, os resultados mostraram que saponinas de Q. brasiliensis são seguras e seus potencial adjuvante foi equivalente a saponinas com ação imunoadjuvante conhecida de Q. saponaria. / Effective vaccine formulations frequently require addition of adjuvants able to optimize the cellular and humoral immune responses. With the goal to contribute to the development of new classes of adjuvants, this work was developed in order to achieve deep knowledge on the imunoadjuvant mode of action for Quillaja brasiliensis saponins incorporated into immunostimulant complex (ISCOM). The toxicity of saponins is a critical factor for its usage as vaccine preparations. At first, in vivo and in vivo citoxicity assays were carried out to compare to the effects between saponins extracted from Quillaja brasiliensis and the immunostimulant saponins already known from Quillaja saponaria (Quil A). Imunoadjuvant potential of soluble saponins from Q. brasilienis was evaluated using preparations of two antigens: ovoalbumin (OVA) and bovine viral diarrhea (BVD). As a next step, imunoadjuvant activity of ISCOMS prepared with Q. brasiliensis saponins was evaluated using two routes of administration. The immunomodulatory potential of these saponins was tested during in vivo cell recruitment assays and gene expression related to immune system. Our results demonstrated that Q. brasilienis saponins are less toxic than those from Quil A and presenting similar adjuvant activity, characterized by a Th1/Th2 balance profile. Q.brasiliensis induced a strong Th1 cell-mediated immune responses indicated by a robust delayed type hypersensitivity (DTH) as well as IFN-у and IL-2 production. The immune response induced by ISCOMs from Q. brasiliensis saponins was higher than the one induced by soluble saponins. In vivo experiments indicated that saponins from Q. brasiliensis generate an immunocompetent environment at the injection site and draining lymph nodes. This environment was characterized by an intense cell influx (neutrophils, NK cells, dendritic cells, B and T cells) as well as differential gene expression related to immune system activation. In essence, the results showed that saponins from are safe and their adjuvant potential was equivalent to saponins with imunoadjuvant activity of Q. saponaria.

京都大学 / 0048 / 新制・論文博士 / 博士(医学) / 乙第13378号 / 論医博第2212号 / 新制||医||1047(附属図書館) / (主査)教授 井上 治久, 教授 髙橋 良輔, 教授 渡邉 大 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM

No description available.

Enveloped RNA viruses like human immunodeficiency virus type-1 (HIV-1) and SARS-CoV-2 enter host cells through fusion with the plasma membrane, a process facilitated by specific viral envelope proteins that recognize and bind to receptors expressed on the host cell surface. These receptors can diverge based on the type of cell and virus. For HIV-1, the primary receptors on myeloid cells are CD4 and CCR5 or CXCR4. For SARS-CoV-2, although the primary receptor is ACE2, other myeloid-cell specific sialic acid binding lectins can also facilitate entry. Following cellular invasion, different viral RNA species can be detected by distinct host nucleic acid sensors, resulting in type I interferons and pro-inflammatory cytokine induction. While these innate immune responses are essential for controlling viral infections, overactivation can lead to chronic inflammation, tissue damage, and disease pathogenesis. Herein, I examine the contribution of HIV-1 and SARS-CoV-2 de-novo RNA expression and the molecular mechanisms that contribute to innate immune activation in myeloid cells. Despite advancements in combination antiretroviral therapy (ART) in suppressing systemic viral replication in individuals infected with HIV, residual viral RNA expression in tissue reservoirs remains a significant hindrance to curative efforts. I hypothesized that persistent expression of viral RNAs in myeloid cells triggers dysregulated innate immune activation, and inflammasomes activation. This study centers on the long-lived tissue-resident innate immune cells - macrophages and microglia, which, owing to their self-renewing nature, operate as reservoirs of viral RNA production, and are thought to lead to chronic immune activation even in the absence of productive replication. Our previous studies suggest that de novo expression of unspliced intron-containing HIV-1 RNA (herein referred to as icRNA) triggers activation of pro-inflammatory cytokines in myeloid cells. Here, I demonstrate that cytosolic expression of HIV-1 icRNA, but not multiply-spliced viral RNAs induces inflammasome activation, LDH release and IL-1β secretion in productively infected monocyte-derived macrophages (MDM) and induced pluripotent stem cell (iPSC)-derived microglia. Interestingly, knockdown of RLRs, RIG-I and MDA5 or endosomal TLRs failed to abrogate HIV-1 icRNA-induced IL-1β secretion. Rather, knockdown of NLRP1, but not NLRP3, inflammasome resulted in a significant reduction in IL-1β secretion, underscoring NLRP1's pivotal role in the HIV-1 icRNA-induced IL-1β secretion. Furthermore, Rev-Crm1-dependent nucleocytoplasmic export of HIV-1 icRNA was required for NLRP1-mediated Caspase-1 activation, IL-1β secretion, LDH release and cell death. Similarly, SARS-CoV-2, while not establishing productive infection in macrophages, can activate these cells, contributing to a hyper-inflammatory response marked by the heightened expression of pro-inflammatory cytokines, which is understood to be a principal driver of COVID-19 pathology. SARS-CoV-2 established an abortive infection in macrophages. CD169, a macrophage-specific sialic-acid binding lectin, mediated ACE2-independent SARS-CoV-2 entry in human macrophages and establishment of restricted infection. Interestingly, CD169-mediated SARS-CoV-2 entry in macrophages led to the expression of viral genomic and subgenomic RNAs, with negligible viral protein expression and no release of infectious virus particles, implying a post-entry restriction to SARS-CoV-2 replication in macrophages that was curbed by exogenous ACE2 expression. Despite restricted viral RNA expression, cytoplasmic RLRs, RIG-I and MDA5, sensed abortive viral transcripts, and induced pro-inflammatory responses in a MAVS dependent manner. This dissertation reveals striking parallels between the role of viral RNAs in driving pro-inflammatory responses in HIV-1 and SARS-CoV-2 infections. These findings collectively underscore the central role of cytoplasmic sensing of viral RNAs and their contribution to chronic inflammation in virus-infected myeloid cells. Elucidating these molecular mechanisms further may pave the way for novel therapeutic interventions to mitigate the persistent innate immune activation and immunopathology detected in HIV-1 and SARS-CoV-2 infected individuals.

Psychiatric disorders are believed to result from the combination of genetic predisposition and many environmental triggers. While the large number of disease-associated genetic variations have been recognized by previous genome-wide association studies (GWAS), the role of epigenetic mechanisms that mediate the effects of environmental factors on CNS gene activity in the etiology of most mental illnesses is still largely unclear. A growing body of evidence suggested that the abnormalities (changes in gene expression, formation of neural circuits, and behavior) involved in most psychiatric syndromes are preserved by epigenetic modifications identified in several specific brain regions. In this thesis, we developed the second generation of one of our microfluidic technologies (MOWChIP-seq) and used it to profile genome-wide histone modifications in three mental illness-related biological studies: the effect of psychedelics in mice, schizophrenia, and the effect of maternal immune activation in mice offspring. The second generation of MOWChIP-seq was designed to generate histone modification profiles from as few as 100 cells per assay with a throughput as high as eight assays in each run. Then, we applied the new MOWChIP-seq and SMART-seq2 to profile the histone modification H3K27ac and transcriptome, respectively, using NeuN+ neuronal nuclei from the mouse frontal cortex after a single dose of psychedelic administration. The epigenomic and transcriptomic changes induced by 2,5-Dimethoxy-4-iodoamphetamine (DOI), a subtype of psychedelics, in mouse neuronal nuclei at various time points suggest that the long-lasting effects of the psychedelic are more closely related to epigenomic alterations than the changes in transcriptomic patterns. Next, we comprehensively characterized epigenomic and transcriptomic features from the frontal cortex of 29 individuals with schizophrenia and 29 individually matched controls (gender and age). We found that schizophrenia subjects exhibited thousands of neuronal vs. glial epigenetic differences at regions that included several susceptibility genetic loci, such as NRXN1, RGS4 and GRIN3A. Finally, we investigated the epigenetic and transcriptomic alterations induced by the maternal immune activation (MIA) in mice offspring's frontal cortex. Pregnant mice were injected with influenza virus at GD 9.5 and the frontal cortex from mice pups (10 weeks old) were examined later. The results offered us some insights into the contribution of MIA to the etiology of some mental disorders, like schizophrenia and autism. / Doctor of Philosophy / While this field is still in its early stage, the epigenetic studies of mental disorders present promise to expand our understanding about how environmental stimulates, interacting with genetic factors, contribute to the etiology of various psychiatric syndromes, like major depression and schizophrenia. Previous clinical trials suggested that psychedelics may represent a promising long-lasting treatment for patients with depression and other psychiatric conditions. These research presented the therapeutic potential of psychedelic compounds for treating major depression and demonstrated the capability of psychedelics in increasing dendritic density and stimulating synapse formation. However, the molecular mechanism mediating the clinical effectiveness of psychedelics remain largely unexplored. Our study revealed that epigenomic-driven changes in synaptic plasticity sustain psychedelics' long-lasting antidepressant action. Another serious mental illness is schizophrenia, which could affect how an individual feels, thinks, and behaves. Like most other mental disorders, schizophrenia results from a combination of genetic and environmental causes. Epigenetic marks allow a dynamic impact of environmental factors, including antipsychotic medications, on the access to genes and regulatory elements. Despite this, no study so far has profiled cell-type-specific genome-wide histone modifications in postmortem brain samples from schizophrenia subjects or the effect of antipsychotic treatment on such epigenetic marks. Here we show the first comprehensive epigenomic characterization of the frontal cortex of 29 individuals with schizophrenia and 29 matched controls. The process of brain development is surprisingly sensitive to a lot of environmental insults. Epidemiological studies have recognized maternal immune activation as a risk factor that may change the normal developmental trajectory of the fetal brain and increase the odds of developing a range of psychiatric disorders, including schizophrenia and autism, in its lifetime. Given the prevalence of the coronavirus, uncovering the molecular mechanism underlie the phenotypic alterations has become more urgent than before, for both prevention and treatment.

Résumé : Le streptocoque de groupe B (SGB) est une bactérie commensale présente dans le tractus génito-urinaire de 10 à 30 % des femmes enceintes en santé. Ce pathogène est responsable de chorioamnionite, associée aux naissances prématurées et aux dommages cérébraux du nouveau-né. Les infections durant la grossesse, la chorioamnionite et la prématurité sont associées au développement de troubles du spectre de l’autisme. Notre hypothèse est qu’une exposition subclinique au SGB induit une réponse inflammatoire maternofoetale, menant à des troubles neurodéveloppementaux et comportementaux de type autistique dans la progéniture. L’objectif principal est d’étudier, à l’aide d’un nouveau modèle animal (rat) préclinique, les impacts d’une exposition au SGB en période prénatale sur le développement cérébral de la progéniture. Les rates Lewis gestantes sont injectées au jour de gestation 19 avec une dose de SGB de sérotype Ia (108 UFC/100µl) ou de saline. La réponse inflammatoire placentaire est caractérisée par immunohistochimie. Des tests comportementaux sont effectués entre les jours postnataux 7 et 40 afin d’évaluer la communication, le comportement exploratoire, l’intégration sensorielle et les interactions sociales. Une chorioamnionite dichotomique selon le genre est observée dans les placentas exposés au SGB, via une infiltration de cellules polymorphonucléaires. Cette infiltration est significativement plus proéminente dans les placentas associés aux fœtus mâles que ceux des fœtus femelles. Les mâles exposés au SGB ont un amincissement de la substance blanche cérébrale adjacente aux ventricules latéraux élargis. La progéniture mâle exposée au SGB présente des anomalies comportementales associées aux traits cardinaux des troubles du spectre de l’autisme, soit des déficits au niveau de la communication, des interactions sociales, du traitement de l’information sensorielle ainsi qu’au niveau d’autres comorbidités classiques de l’autisme, comme l’hyperactivité. Ces données démontrent pour la première fois que l’activation immune maternelle induite par l’infection au SGB joue un rôle dans l’induction d’anomalies neurodéveloppementales récapitulant celles observées chez les patients autistes, incluant la dichotomie de genre et le phénotype neurocomportemental. Ces résultats fournissent de nouvelles évidences en faveur du rôle dans la physiopathologie de l’autisme d’un facteur environnemental commun, et modifiable, d’inflammation gestationnelle. / Abstract : Group B Streptococcus (GBS) is a commensal bacterium present in the vagina of 10 to 30% of healthy pregnant women. GBS is responsible for chorioamnionitis, which can cause preterm birth and cerebral injuries in the newborn most often in the absence of maternofetal pathogen translocation. Maternal infection, chorioamnionitis and preterm birth are associated to autism spectrum disorders (ASD) in the progeny. Our hypothesis is that GBS-induced gestational infection induces a maternofetal inflammatory response leading to neurodevelopmental impairments and ASD-like behaviour in the offspring. Our goal was to study, with a new preclinical animal model, the impacts of GBS-induced gestational inflammation on the neurodevelopmental features in the offspring. We characterized GBS-induced placental and neurobehavioural outcomes. Dams were exposed at gestational day 19 to live GBS or saline. The placental inflammatory response was studied by immunohistochemistry. Behavioural tests were performed between postnatal days 7 and 40 to assess communication, exploratory abilities, sensory integration and social interactions. GBS-exposed placentas displayed chorioamnionitis featured by infiltration of polymorphonuclear cells, which was significantly more prominent in males than in females. GBS-exposed males showed a reduced thickness of periventricular white matter. Male offspring exposed to GBS had early onset of cardinal ASD-like traits affecting social interaction, communication (ultrasonic vocalizations), treatment of sensory information (prepulse inhibition), preference toward mother cue (nest-seeking), and some other classic ASD comorbidities such as hyperactivity (open field). Overall, these data show for the first time that maternal immune activation due to live GBS plays a key role in the induction of neurodevelopmental abnormalities recapitulating those of human ASD, including gender dichotomy and neurobehavioural phenotype. These results provide new evidence in favor of the role of a common and modifiable infectious/inflammatory environmental factor in human ASD pathophysiology.

Introdução: O câncer de pulmão (CP) é o tipo de câncer que mais mata no mundo e o cigarro ainda é sua causa mais importante. Além disso, a alimentação tem sido associada ao CP, por ser fonte de vitaminas e aminoácidos que fazem parte do metabolismo do carbono (MC). O MC é considerado mecanismo chave na manutenção da integridade do DNA e na regulação da expressão gênica, que, dessa forma, deve estar relacionado à carcinogênese. A ativação da imunidade está associada ao envelhecimento em indivíduos saudáveis, assim como a uma série de patologias, incluindo o câncer. Objetivo: Estudar como o MC, a ativação da imunidade e o tabaco estão relacionados ao risco de CP em um estudo caso-controle aninhado à coorte do EPIC (European Prospective Investigation into Cancer and Nutrition). Métodos: Para avaliar se os níveis plasmáticos de cotinina são um bom biomarcador da exposição ao tabaco, foram utilizados modelos lineares generalizados. Para avaliar os efeitos do tabaco, do MC e da ativação da imunidade no risco de CP, foram aplicados modelos de equações estruturais (MEE) de duas maneiras diferentes (com e sem variáveis latentes). Resultados: Com base nas respostas aos questionários de qualidade de vida, com relação às questões sobre fumo ativo e passivo, a cotinina se mostrou um bom biomarcador de exposição recente ao tabaco (tanto o aumento da exposição passiva quanto ativa foram significativas, P<0,001 e P<0,001 respectivamente). Em um MEE com variáveis observadas, incluindo o MC e a via de ativação da imunidade, a metionina e o folato como causas proximais apresentaram uma forte e inversa associação com o risco de CP. O aumento em um desvio-padrão nos níveis séricos de metionina e de folato significou uma redução no risco de 19 por cento (P<0,01) e 12 por cento (P=0,03) respectivamente. Em um MEE com variáveis latentes (cada uma representando o conjunto de vitaminas e aminoácidos importantes para promover: metilação de DNA, síntese de núcletídeos e imune ativação), foram encontrados efeitos protetores diretos da metilação do DNA (P=0,018) e da imune ativação (P=0,037); por outro lado, a síntese de nucletídeos não apresentou efeito no risco do câncer (P=0,098). Nas duas abordagens de MEE o cigarro permaneceu como a causa de maior impacto. Conclusões: A cotinina mostrou-se um bom biomarcador da exposição ao tabaco (ativa e passivamente). Confirmou-se que a via de metilação é um fator de proteção contra o CP. A ativação da imunidade apresentou um efeito direto de proteção contra o CP no modelo com variáveis latentes, equanto que, a síntese de nucletídeos não apresentou relação com o CP. O tabaco continua sendo o fator de maior impacto no risco de CP / Background: Lung cancer (LC) continues to be the most common cancer death in the world. Tobacco exposure continues to be the most important cause. In addition, micronutrient intake has been linked to LC, because they are the main source of vitamins and amino acids involved in the one-carbon metabolism (OCM) which is considered key in maintaining DNA integrity, regulating gene expression, and may thus affect carcinogenesis. Immune activation is involved in the aging process in normal healthy individuals as well as in a number of pathologies, including cancer. Objectives: To investigate how OCM, immune activation and tobacco are related to LC incidence in a nested case-control study from the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. Methods: To validate plasma cotinine levels as a good biomarker for tobacco exposure, a generalized linear model was applied. To evaluate the effects of tobacco, OCM and immune activation in LC, structural equation models (SEM) were applied in two different ways. Results: Based on questions about smoking, passive smoking and number of cigarettes smoked, it was shown that cotinine is a good biomarker for tobacco exposure (passive and active exposure with significant relation, p<0.001 and P<0.001, respectively). In a SEM model with only observed variables, including OCM and immune activation, methionine and folate as proximal causes presented a strong and inverse relation with LC risk. An increase in one standard deviation of serum levels of methionine and folate meant a 19 per cent (P<0.01) and 12 per cent (P<0.01) reduction in LC risk, respectively. In a SEM including latent variables (each one including vitamins and amino acids important to promote DNA methylation, nucleotide synthesis and immune activity), a direct and protective effect for DNA methylation (p=0.018) and immune activation was found (p=0.037), whereas nucleotide synthesis did not present a significant total effect. In both approaches of SEM, tobacco exposure remains with the highest impact on LC risk. Conclusions: It was found that cotinine is a good biomarker of tobacco exposure (active and passive). It was confirmed that methylation protects against LC. Immune activation presented a direct protective effect in the latent model, while nucleotide synthesis was not confirmed to be related to LC risk. Tobacco effect remains as the factor with highest impact in lung cancer

Schizophrenia is a mental illness with early adult onset. Prophylactic treatments would be clinically important and therefore we investigated the effect of two interventions: influenza vaccination of pregnant mothers and valproate treatment during late adolescence. Maternal immune response during pregnancy is thought to adversely affect brain development. We sought to assess whether immune activation by influenza vaccine could itself cause behavioural abnormalities in a mouse model. Our data suggest that further work is needed to make firm conclusions about the behavioural effects of the influenza vaccine. The second part of this thesis describes an analysis of valproate treatment on cortical neuron morphology in Disc1 L100P mice, a model for schizophrenia. Valproate was previously shown to prevent the onset of abnormal behaviours in Disc1 L100P mice. Contrary to expectations, valproate decreased apical spine density and the number of dendritic processes rather than reversing the dendritic deficits seen in Disc1 L100P mice.

Schizophrenia is a mental illness with early adult onset. Prophylactic treatments would be clinically important and therefore we investigated the effect of two interventions: influenza vaccination of pregnant mothers and valproate treatment during late adolescence. Maternal immune response during pregnancy is thought to adversely affect brain development. We sought to assess whether immune activation by influenza vaccine could itself cause behavioural abnormalities in a mouse model. Our data suggest that further work is needed to make firm conclusions about the behavioural effects of the influenza vaccine. The second part of this thesis describes an analysis of valproate treatment on cortical neuron morphology in Disc1 L100P mice, a model for schizophrenia. Valproate was previously shown to prevent the onset of abnormal behaviours in Disc1 L100P mice. Contrary to expectations, valproate decreased apical spine density and the number of dendritic processes rather than reversing the dendritic deficits seen in Disc1 L100P mice.