Degree awarded with distinction on 6 December l995. A dissertation submitted to the Faculty of Science, University the Witwatersrand, in fulfilment of the requirements for the degree of Master of Science. March. 1995 / Hepatitis B virus (HBV) infection resulting in integration of the viral DNA into host liver cell DNA is associated with the development of hepatocellular carcinoma (HCC). This is indicated by epidemiological trends, molecular studies and studies of animal models infected with viruses closely related to HBv. However, little is known about the mechanism by which the integrated HBV DNA includes HCC despite continuing analysis of the integrated HBV DNA and its surrounding cellular sequences. [Abbreviated Abstract. Open document to view full version]

Ph.D. thesis, Faculty of Health Sciences,University of the Witwatersrand, 2009 / Hepatitis B virus (HBV) infection is endemic in Africa. As many as 98% of black Africans are infected during their lives and about 10% (65 million) have chronic HBV infection, which is the cause of 70-80% of all hepatocellular carcinoma (HCC) cases. Despite this high prevalence of HBV and the high incidence of HCC in Africa, relatively few complete HBV genomes from African HCC cases have been deposited in international data bases. In order to gain a clearer understanding of the role of genetic variants and mutants in the development of HCC, the complete genomes of HBV isolated from southern African HCC patients were amplified and molecularly characterized. HBV DNA was extracted from the serum forty HBsAgpositive HCC patients. Twenty six complete genomes were successfully amplified, cloned and sequenced from nine HCC patients. Phylogenetic analyses of the complete genomes and the individual open reading frames of HBV isolates from the HCC patients, led to the classification of all the isolates within subgenotype A1. No isolates belonging to subgenotype A2 and genotype D were identified, even though these genotypes/subgenotypes have been shown to circulate in South Africa. Three patients contained the uncommon combination of serological subtype ayw1 in the subgenotype A1 strain. This combination has been found previously in South Africa and the Phillipines. Seventy-eight percent of the patients carried HBV strains with the double basic core promoter (BCP) mutation (1762T/1764A), previously shown to reduce HBeAg expression. Furthermore, complete genome sequence analysis has revealed a complex combination of mutations, which include at least three or five of these residues 1753C1762T1764A1766T1768A1809T1812T occurring as the dominant HBV strains isolated from 5/9 HCC patients. These mutations have previously been shown to regulate gene expression at various levels, to enhance viral replication and simultaneously decrease HBeAg expression. All five HBV genomes isolated from one patient contained novel complex BCP rearrangements, which introduced 2 HNF1 and 1 putative HNF3 transcription factor binding sites. These mutations can enhance viral replication and simultaneously abolish HBeAg expression at a transcriptional level. Furthermore, truncated core proteins would be expressed from 4/5 isolates and none would express wild-type HBx. Several mutations were identified in the pre-S/S genes of 2/5 isolates, which would result in the expression of novel 3’ truncated medium surface proteins (MHBst) and large surface proteins (LHBst). The majority of the mutations would contribute to hepatocyte pathogenesis and transformation by activating cell proliferating pathways. Two patients also contained rare HBV variants not previously identified in HBV strains from southern Africa. These included an HBV splice variant and a poly (dA) variant from patient 10 and patient 6, respectively. These variants occurred in combination with other isolates within the respective patients. The envelope genes were characterised in a total of 18 HCC patients, the pre-S gene of HBV contained deletions in 72% of the patients. Deletions across pre- S1/pre-S2, pre-S2 initiation codon mutations with internal deletions, and S gene nonsense mutations were prevalent. Mutated envelope proteins have been shown to accumulate within the hepatocyte endoplasmic reticulum (ER) and are a characteristic histopathological hallmark of HCC known as ground glass hepatocytes. HBV induced ER stress has been shown to dysregulate several cell cycle regulatory pathways, which contribute to HCC. In addition several novel LHBst and MHBst have been described. These potential transactivators require further investigation. The HBV mutations described in this study have been associated with increased risk for HCC. Despite the obvious heterogeneity HBV displays within and between patients, there are common characteristics shared between the HBV variants which emerge during the development of HCC. These include the BCP and pre-C (1753C1762T1764A1766T1768A1809T1812T) mutations and the pre-S/S mutations. These mutations are able to affect HBV replication and gene expression, and may work synergistically to promote liver dysfunction and HCC.

MSc (Med), Faculty of Health Sciences, University of the Witwatersrand, 2011 / Despite being a fulminant pathogen, Neisseria meningitidis (meningococcus) is part of the commensal flora of the human nasopharynx. Globally, five meningococcal serogroups (A, B, C, Y and W135) cause the majority of invasive disease. Most serogroup B cases occur sporadically but may be endemic or epidemic within a geographic region. In South Africa, there are limited data on invasive serogroup B clones and the antigenic diversity of certain meningococcal outer membrane proteins. This study examined the molecular epidemiology of serogroup B meningococci in South Africa from 2002 through 2006. Invasive meningococcal isolates were submitted to a national laboratory-based surveillance system. For this study, serogroup B isolates were characterised by pulsed-field gel electrophoresis (PFGE), PorA, FetA and multilocus sequence (MLST) typing. PorA, FetA and multilocus sequence (MLST) typing were performed on all 2005 isolates (n=58) and randomly selected isolates from other years (n=25). A total of 2144 invasive cases were reported over the study period. Of these, 76% (1627/2144) had viable isolates available for serogrouping and 307 (19%) were serogroup B. Serogroup B cases were reported from across the country however the majority were from the Western Cape province. The highest incidence of serogroup B was in children less than 5 years of age. Isolates displayed a high level of diversity by PFGE. Despite this diversity the majority of serogroup B meningococci collected over the 5-year period could be grouped into several clonal clusters representative of global invasive MLST clonal complexes. Overall, the most predominant MLST clones in South Africa were ST-32/ET-5 and ST-41/44/lineage 3. In addition, at least 19 PorA types and 16 FetA types were determined among selected isolates. Globally invasive serogroup B disease is caused by heterogeneous strains however, prolonged outbreaks in several countries have been due to strains of the ST-32/ET-5 and ST-41/44/lineage 3 clonal complexes. At present, serogroup B disease in South Africa is not dominated by an epidemic clone, however, global clonal complexes ST-32/ET-5 and ST-41/44/lineage 3 are circulating in Western Cape and Gauteng, respectively.

Hepatitis B virus (HBV), the prototype member of the family Hepadnaviridae, is hepatotropic and replicates by reverse transcription. HBV is responsible for the chronic infection of more than 240 million people worldwide, of which 65 million reside in Africa. The nine HBV genotypes (A to I) identified to date, are geographically distributed and exhibit different clinical manifestations and treatment responses. The term occult HBV infection (OBI) refers to a HBV infection in which HBV surface antigen (HBsAg) cannot be detected by conventional serological assays as has been defined by the Taormina expert panel. . HBV and human immune deficiency virus (HIV) are both endemic in many parts of the world and share common transmission routes. Worldwide, 10% of those infected with HIV are also chronically infected with HBV. HIV co-infection has been shown to be a risk factor for the development of OBI in individuals infected with HBV. The aim of this study was to characterize, at the molecular level, HBV from mono-infected and HBV/HIV co-infected individuals in Sudan The objectives of this study were the systematic and comparative analysis of HBV genotype D sequences, available in the public databases; the molecular characterization of HBV from mono-infected Sudanese liver disease patients and from HBV/HIV co-infected Sudanese patients; and the development and testing of bioinformatics tools to explore HBV sequence data generated using ultradeep pyrosequencing (UDPS) and comparison of UDPS results with those obtained from cloning based sequencing (CBS). All available complete genomes of genotype D of HBV from the GenBank database were analyzed. The intra-group divergence of the subgenotypes ranged from 0.8% + 0.5 for subgenotype D6 to 3.0% + 0.3 for subgenotype D8. Phylogenetic analysis of genotype D showed separation into six distinct clusters (subgenotypes D1, D2, D3/D6, D4, D5 and D7/D8), with good bootstrap support. The mean intergroup divergence between subgenotype D3 and subgenotype D6 was 2.6%, falling below the accepted threshold of 4% required to define a subgenotype. This suggests that subgenotypes D3 and D6 are the same subgenotype because they also share signature amino acids. Furthermore, subgenotype D8 is a genotype D/E recombinant, which clusters with subgenotype D7. This analysis provided an update on the classification of the subgenotypes of genotype D of HBV. Although HBsAg seroprevalence in Sudan, a central-African country, is greater than 8%, the only sequencing data for HBV, available prior to our study, was from asymptomatic blood donors, where genotype E predominates, followed by genotype D and subgenotype A2. Ninety-nine HBV-positive liver disease patients were enrolled in our study, including: 15 with hepatocellular carcinoma (HCC), 42 with cirrhosis, 30 asymptomatic carriers, 7 with acute hepatitis and 5 with chronic hepatitis. The surface and basic core promoter/precore (BCP/PC) regions, and the complete genome of HBV were sequenced. Eighty-two percent of the samples from HBV mono-infected liver disease patients were genotyped. Fifty-nine percent were infected with genotype D (74% D1, 10% D2, 3% D3 and 13% D6), 30% with genotype E, 8.5% with genotype A and 2.5% with a genotype D/E recombinant. Patients infected with genotype E had a higher frequency of HBeAg-positivity (29.2%) and higher viral loads compared to patients infected with genotype D. BCP/PC region mutations, including the G1896A mutation, seen in 37% of the HBeAg-negative individuals, could account for the HBeAg-negativity. A total of 358 Sudanese HIV-positive patients were enrolled. HBsAg was detected in 11.7% of the participants, indicating chronic HBV infection. HBV DNA was detected in 26.8% of the participants: 11.7% were HBsAg positive (overt infection) and the remaining 15.1% were HBsAg-negative (OBI). Fifty serum samples from the HBV/HIV DNA-positive co-infected participants were selected for genomic analysis of HBV. Of these, the HBV genotype of 37 was determined. The genotype distribution of HBV isolates from the HBV/HIV co-infected participants did not differ significantly from those from the HBV mono-infected patients: genotype D (46%), E (21.6%), A (18.9%) and a D/E recombinant (13.5%). Compared to the HBV isolates from mono-infected liver disease patients, the frequency of the D/E recombinant and genotype A was higher in HBV/HIV co-infected patients, as was the intragroup divergence of genotype E. No difference in BCP/PC mutations affecting HBeAg expression at the transcriptional and translational levels between genotype D and E was observed. The following mutations could account for the HBsAg-negativity: sM133T, sE164G, sV168G and sS174N. No primary drug resistance mutations were found. Two online bioinformatics tools, the ―Deep Threshold Tool (DDT)‖ and the ―Rosetta Tool‖, were built to analyze data generated from UDPS and CBS of the BCP/PC region of four Sudanese serum samples, infected with either genotype D or E of HBV, from HBeAgpositive and HBeAg negative patients. A total of 10952 reads were generated by UDPS on the 454 GS Junior platform. The Threshold was calculated using DDT based on probability of error of 0.5%. In total, 39 unique mutations were identified by UDPS, of which 25 were nonsynonymous. The ratio of nucleotide substitutions between isolates from HBeAg-negative and HBeAg-positive patients was 3.5:1. From the sequences analyzed, compared to genotype E isolates, genotype D isolates showed greater variation in the X, BCP/PC/C regions. Only 18 of the 39 positions identified by UDPS were detected by CBS. Using the specific criteria, that have been suggested previously, to define genotypes/subgenotypes of HBV, we determined that genotype D has six and not eight subgenotypes. The importance of HBV genotypes in clinical consequences of infection and response to antiviral treatment has led us to characterize HBV genotypes circulating in Sudan. HBV mono-infected patients and HBV/HIV co-infected individuals, were mainly infected with genotype D or E. HBV mono-infected patients, infected with genotype E, had higher HBeAg-positivity and higher viral loads than those infected with genotype D. The ratio of genotype A to non- A, as well as the genotype E intra-group divergence were higher in HBV/HIV co-infected individuals compared to HBV mono-infected individuals. OBI was found in 15.1% HBV/HIV co-infected patients and its clinical relevance remains to be determined. In order to overcome the limitations of Sanger sequencing, which include its high cost and inability to detect minor populations in quasispecies, next generation sequencing techniques have been developed. It was demonstrated that correct analysis of UDPS data required appropriate curation of read data, in order to clean the data and eliminate artefacts and that the appropriate consensus (reference) sequence should be used in order to identify variants correctly. CBS detected fewer than 50% of the substitutions detected by UDPS. This new technology may allow the detection of minor variants between the different genotypes of HBV and provide biomarkers for the prediction of clinical manifestation of HBV and response to antiviral therapy.

INTRODUÇÃO: A hepatite B é uma enfermidade para a qual não existe tratamento curativo efetivo e que pode determinar graves conseqüências, como o desenvolvimento de cirrose e carcinoma hepático. Segundo dados da OMS, mais de dois bilhões de pessoas estão infectadas pelo vírus da hepatite B e esta doença é responsável por 500.000 a um milhão de óbitos por ano, em todo o mundo. Em pacientes com infecção pelo HIV, é freqüente a co-infecção pelo vírus da hepatite B, pelo fato de serem vírus que compartilham modos semelhantes de transmissão. Em vista dessa problemática, a adequada imunização dos pacientes infectados pelo vírus HIV é fundamental para a prevenção da hepatite B. A recomendação atual do Ministério da Saúde para vacinação de crianças HIV-positivas é a realização do esquema de quatro doses (zero, um, seis e doze meses), com dose dupla. OBJETIVOS: Estudar a resposta sorológica ao booster com vacina da hepatite B em crianças HIV-positivas, previamente vacinadas com três doses duplas que não apresentaram títulos protetores. Estudar a associação dos níveis de CD4 e carga viral no momento do booster. Estudar a associação do intervalo de tempo entre a primovacinação e a primeira avaliação sorológica com a presença de títulos protetores, bem como a associação do intervalo de tempo entre a terceira dose vacinal e o booster com a presença de títulos protetores. METODOLOGIA: O presente trabalho é um estudo prospectivo descritivo de uma coorte de 70 crianças com HIV do total de 187 matriculadas em seguimento no ambulatório de Infectologia do Instituto da Criança (HCFMUSP), no período de agosto de 2005 a novembro de 2006. Em um primeiro momento, realizou-se a dosagem sorológica do anti-HBs dos pacientes que preencheram os critérios de inclusão. Em um segundo momento, nos pacientes que não apresentaram títulos de anti-HBs maiores que 10 mUI/mL, aplicou-se a dose booster da vacina (20 g). Realizou-se dosagem sorológica nos pacientes que receberam a dose booster, no período de um a três meses depois. RESULTADOS: Observou-se que a maioria dos pacientes (50 = 71,4%) não apresentava títulos de anti-HBs >10 mUI/mL no momento da primeira avaliação laboratorial. A média do intervalo de tempo entre a terceira dose da vacina e a dosagem sorológica nos pacientes que apresentaram títulos protetores foi de 53,8 meses, enquanto que a média de tempo no grupo que não apresentou títulos protetores foi de 74,0 meses (p = 0,007). A freqüência de títulos não protetores após dose booster foi de 68%, enquanto apenas 32% apresentaram sorologia protetora após booster. Os dados deste estudo não mostraram associação estatisticamente significante entre níveis de CD4 e carga viral com resposta à dose booster. CONCLUSÕES: O estudo do intervalo de tempo entre a última dose da primovacinação e a feitura da sorologia sugere haver uma tendência à queda de títulos protetores (anti-HBs) ao longo do tempo. Após a dose dupla do booster, ainda se manteve uma predominância de não-resposta sorológica ou resposta com títulos não protetores à vacina da hepatite B nas crianças com HIV, neste estudo. / INTRODUCTION: Hepatitis B is a disease for which there is no effective healing treatment and which can bring about such severe consequences as cirrhosis and hepatocellular carcinoma . According to the World Health Organization (WHO), more than two billion people are currently infected with the hepatitis B virus and the disease is responsible for half a million to one million deaths a year worldwide. Coinfection with hepatitis B virus is common in HIV-infected patients, since both viruses share similar transmission means. Within this context, adequate immunization of HIV-infected people is crucial for hepatitis B prevention. The current recommendation from the Ministry of Health in Brazil for HIV-positive children vaccination is the four-dose schedule (0, 1,6 and 12months) with a double dose. OBJECTIVES: Study the serologic response to a booster dose with the hepatitis B vaccine in HIV-infected children who had been previously vaccinated with three double doses but did not present protective titles. Study the relationship of CD4 levels and the viral load with protective titles at the time of the booster. Study the relationship between the time gap from the first vaccination to the first serologic evaluation and the presence of protective titles, as well as the relationship between the time gap from the third vaccine dose to the booster and the presence of protective titles. METHODOLOGY: The present research consists of a prospective descriptive study of a sample of 70 HIV-infected children out of a total of 187 children enrolled in a follow-up program at the Infectology sector of the Instituto da Criança (Childrens Institute HCFMUSP) from August 2005 through November 2006. First of all, the patients who met the admission criteria had their anti-HBs serologic titles tested. Then the ones whose anti-HBs serologic titles were lower than 10 mUI/mL received a vaccine booster (20 g). Those patients who received the booster had their serologic titles tested again between one and three months after that. RESULTS: It was found that most patients (50=71.4%) did not present anti-HBs serologic titles > 10 mUI/mL at the moment of the first laboratory evaluation. The average time gap between the third dose of the vaccine and the serologic testing of the patients who presented protective titles was of 53.8 months, while the average time in the group who lacked protective titles was of 74 months (p=0.007). The rate of no protective titles after the booster dose in those patients was 68%; on the other hand, only 32% presented protective serology after the booster. The studys data did not show a statistically significant relationship between CD4 levels and viral load with the response to the booster dose. CONCLUSIONS: The study of the time gap between the last dose of the first vaccination and the serology testing suggests that the protective titles (anti-HBs) tend to decrease with time. The serologic lack of response or the nonprotective titles response to hepatitis B vaccine prevailed in the study sample of HIV-infected children even after they received the booster double dose.

A vacinação é o método mais importante, barato e eficaz que se tem para a prevenção da transmissão do vírus da hepatite B (VHB). A vacina é indicada para indivíduos renais crônicos devido ao risco acrescido para aquisição do VHB durante a hemodiálise e a transfusão de sangue ou derivados. É indicado que a vacina seja administrada o mais precocemente possível ao entrar no programa de diálise, enquanto os indivíduos são bons respondedores. Este estudo teve como objetivo avaliar o monitoramento do anticorpo anti-HBs vacinal contra a hepatite B em pacientes renais crônicos, que iniciaram hemodiálise no ano de 2005 e permaneceram em seguimento por até quatro anos, em Ribeirão Preto-SP. Trata-se de um estudo de coorte retrospectivo, desenvolvido em quatro unidades de hemodiálise que atendiam indivíduos portadores de DRC na cidade de Ribeirão Preto. A fonte de informação foi composta pela revisão de prontuários de saúde e a população do estudo foi constituída por 102 indivíduos renais crônicos. Dos 102 (100%) participantes, 58,8% eram do sexo masculino e a faixa etária predominante foi <= 45 anos; 52,3% foram a óbito; 18,5% foram submetidos a transplante renal; 20% transferidos; e, em 9,2% dos casos, as razões da interrupção do seguimento não estavam descritas nos prontuários. A proporção de indivíduos que receberam o esquema vacinal completo contra hepatite B foi de 35,3%; em 94,4% dos indivíduos, o tipo de esquema vacinal realizado foi de três doses de 40 mcg e, em 5,6%, o de quatro doses de 40 mcg; o esquema vacinal foi realizado antes do início da hemodiálise em 13,9% dos indivíduos. Em relação à realização da dose de reforço da vacina, 16,7% receberam-na, e o número de doses variou de uma a três doses. A taxa de soroconversão da vacina contra hepatite B, nos hemodialisados que receberam o esquema vacinal completo, foi de 72,2%. Quanto ao teste anti-HBs, no período da admissão na unidade de hemodiálise, 29,4% dos pacientes possuíam registros desse teste. Os títulos de anti-HBs não foram realizados semestralmente em 62,7% dos indivíduos. Ao avaliar a persistência da imunidade da vacina contra hepatite B nos hemodialisados, 39,2% dos indivíduos permaneceram com os títulos de anti-HBs sempre reagentes ao longo do estudo, sendo, portanto, respondedores à vacina contra hepatite B. Conclui-se que a análise dos dados permitiu evidenciar índices insatisfatórios da vacinação contra hepatite B durante o tratamento hemodialítico, bem como dificuldades em seguir o protocolo com esquema vacinal implementado, realização de doses reforço e solicitação de sorologia para anti-HBs. Desta forma, identifica-se a necessidade da equipe de profissionais que atuam em unidades de hemodiálise de adotar, na sua prática, a aplicação de instrumentos que visem facilitar e possibilitar um maior controle e monitoramento da vacinação contra hepatite B e dos títulos de anti-HBs. / Vaccination is the most important, inexpensive and effective method to prevent the transmission of hepatitis B virus (HBV). The vaccine is indicated for individuals with chronic renal failure due to the increased risk for acquiring HBV during hemodialysis and transfusion of blood or derivatives. It is recommended that the vaccine be administered as early as possible to patients entering the dialysis program, while individuals are good responders. This study aimed to evaluate the monitoring of anti- HB antibodies in patients with chronic renal failure who initiated hemodialysis in 2005 and remained in follow-up for up to four years in the city of Ribeirão Preto, state of São Paulo, Brazil. It is a retrospective cohort study which was developed in four hemodialysis units that assist individuals with chronic renal failure in Ribeirão Preto. The source of information was composed of the review of health records and the sample was consisted of 102 individuals with chronic renal failure. Of the 102 (100%) participants, 58.8% were male and the predominant age group was <= 45 years; 52.3% of them died; 18.5% were undergone to kidney transplantation; 20% were transferred; and in 9.2% of the cases, the reasons for discontinuing follow up were not described in the records. The proportion of individuals who received the complete vaccination against hepatitis B was of 35.3%; the vaccination scheme used for immunization in 94.4% of the individuals was of three doses of 40 mcg; and in 5.6% was of four doses of 40 mcg; the vaccination was performed before initiating hemodialysis in 13.9% of individuals. 16.7% of them received the booster dose of vaccine and the number of doses ranged from one to three doses. The seroconversion rate of hepatitis B vaccine in hemodialysis patients who received the full vaccination schedule was of 72.2%. Related to the anti-HBs test in the period of admission to the hemodialysis unit, 29.4% of the patients had records of this test. The titers of anti-HBs were not accomplished every six months in 62.7% of the individuals. Evaluating the persistence of vaccine immunity against hepatitis B virus in hemodialysis patients, 39.2% of the them remained with the titers of anti-HBs always reagents throughout the study, being therefore, responders to the vaccine against hepatitis B. Data analysis highlighted unsatisfactory rates of vaccination against hepatitis B during the hemodialysis treatment as well as difficulties to follow the vaccination protocol implemented, give a booster dose, and request serology for anti-HBs. Thus, it was observed the need for professional staff who works at hemodialysis units to adopt, in their practice, the use of instruments to facilitate and enable greater control and monitoring of hepatitis B vaccination and titers of anti- HBs.

Thesis advisor: Thomas C. Chiles / B-lymphocytes respond to environmental cues for their survival, growth, and differentiation through receptor-mediated signaling pathways. Naïve Blymphocytes must acquire and metabolize external glucose in order to support the bioenergetics associated with maintaining cell volume, ion gradients, and basal macromolecular synthesis. The up-regulation of glycolytic enzyme expression and activity via engaged B-cell receptor mediated-events was glucose-dependent. This suggests an essential role for glucose energy metabolism in the promotion of B cell growth, survival, and proliferation in response to extracellular stimuli. In addition, the activity of ATP-citrate lyase (ACL) was determined to be crucial for ex vivo splenic B cell differentiation to antibody-producing cells wherein B cells undergo endomembrane synthesis and expansion. This investigation employed knockout murine models as well as chemical inhibitors to determine the signaling components and enzymes responsible for glucose utilization and incorporation into membrane lipids. These results point to a critical role for phosphatidylinositol 3- kinase (PI3K) in orchestrating cellular glucose energy metabolism and glucosedependent de novo lipogenesis for B lymphocyte responses. / Thesis (PhD) — Boston College, 2012. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Biology.

Thesis advisor: Welkin Johnson / Thesis advisor: Thomas Chiles / B cell activation is an energetically demanding process during which B lymphocytes undergo reprogramming and shift from a resting state to a highly proliferative, metabolically active state. Little is known about the metabolic reprogramming process or the role extracellular nutrients play in the activation response. Here we demonstrate that there are distinct requirements for the nutrients L-glutamine and glucose during activation. We show that cells activated in glucose-depleted conditions are still able to undergo growth and signaling events. In contrast, we show that extracellular L-glutamine is essential for all but the earliest activation events, and cells cultured in L-glutamine-deprived conditions are unable to enter the cell cycle. Consistently, we show that extracellular supplementation of the cell-permeable derivative of α-ketoglutarate (α-KG), a glutaminolytic product, is able to rescue cell activation in the absence of glutamine. We also show the induction of the high affinity amino acid transporter ASCT2 is required for glutamine uptake following B cell receptor (BCR) crosslinking. Specifically, we found that halting glutamine uptake or processing by inhibiting ASCT2 or the glutaminolytic enzyme glutaminase causes activation defects that parallel those observed in glutamine deprived conditions, indicating a requirement for glutaminolysis during the very early stages of activation. We found that -KG does not contribute to epigenetic remodeling, but is necessary for mammalian target of rapamycin complex 1 (mTORC1) activation. In turn, mTORC1 activity is required for upregulation of the glucose transporter Glut1 during the initial 24 hours of activation, as well as increased glucose uptake. These findings indicate a distinct metabolic profile that begins with glutamine uptake, and acts through mTORC1 signaling to later promote glucose uptake. Finally, we show that nutrients contribute to functional differentiation events during B cell activation. Glucose is required to support biogenesis of the endoplasmic reticulum as well as differentiation into plasma-like cells, while glutamine is required to support differentiation into IL-10 secreting regulatory B cell subsets. The requirement for glutamine for in vitro B10 cell differentiation is the first reported link between nutrient signaling and regulatory B cell development, and is a novel finding in the field. / Thesis (PhD) — Boston College, 2016. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Biology.

Infecção pelo HPV é o principal fator de risco para câncer cervical. Os tumores apresentam microambiente complexo, células tumorais e inflamatórias integram sinais modulando a atividade de vias de sinalização. Caracterizamos o estado de ativação de três vias de sinalização importantes para a progressão tumoral. Com o aumento do grau da lesão, observamos: aumento da expressão de NF&#954;B e Akt fosforiladas no microambiente tumoral; redução de NF&#954;B fosforilada e aumento de STAT3 e Akt fosforiladas em leucócitos circulantes. Em modelos experimentais, a via de NF&#954;B também encontra-se inibida, principalmente em células apresentadoras de antígenos. Para testar se a modulação de vias de sinalização poderiam alterar as respostas a tumores, tratamos linfócitos B de pacientes com agonista de CD40, ativador de NF&#954;B, e observamos aumento do potencial de apresentação antigênica. Nossos resultados mostram o panorama do estado de ativação de importantes vias de sinalização para a progressão tumoral e trazem a possibilidade de uma ferramenta imunomoduladora. / Cervical cancers have HPV infection as a main factor. HPV tumors recruit leucocytes and change their phenotype as an evasion mechanism. We tried to understand how the tumor influences the immune cells behavior, analyzing signaling pathways important to tumor progression in cervical biopsy and PBMC from patients with high-grade lesions and cancer. We find an increase in NF&#954;B activation in immune cells from tumor microenvironment, but a decrease in PBMC. We could not find any difference in STAT3 signaling pathway in the tumor microenvironment, however, there was an activation increase in PBMC. Both tumor microenvironment immune cells and PBMC had an increase in Akt signaling pathway. To identify a possible strategy to reverse the tumor influence, we stimulated B lymphocytes from patients with sCD40L, achieving an increase in the numbers of CD80+CD86+ cells. Our results demonstrate a tumor effect over the immune cells, with an important systemic effect. However, the approach used to stimulate B lymphocytes from patients present us with a possible immunotherapy.

O objetivo principal deste estudo foi avaliar fatores virais associados com a evolução para o carcinoma hepatocelular (CHC) em pacientes com hepatite B crônica. Para tanto caracterizamos os subgenótipos do HBV, investigamos a ocorrência de mutações nos genes pré-core/core do HBV associadas à presença de CHC avaliamos por análise filogenética a associação de linhagens virais com a ocorrência de CHC e por fim a associação de outros fatores de risco com o desenvolvimento de CHC. Foram incluídos 119 amostras de soro de pacientes com infecção crônica pelo HBV, destas amostras 60 pertencem ao grupo 1 (CHC), que são pacientes com diagnóstico confirmado de carcinoma hepatocelular e 59 amostras pertencem ao grupo 2 (sem CHC) que são pacientes com hepatite crônica sem detecção prévia de nódulos hepáticos. Foram obtidas informações acerca da idade, sexo e naturalidade. Além disso, os pacientes responderam a um questionário sobre fatores de riscos associados ao desenvolvimento de CHC. Foram realizados exames bioquímicos, sorológicos, determinação da carga viral, e amplificação por nested PCR e sequenciamento das regiões S/polimerase e pré-core/core do genoma viral para posterior caracterização dos genótipos/subgenótipos do HBV e pesquisa de mutações associadas com evolução da doença hepática. Em relação à idade e sexo não houve grande variação entre os grupos. Quanto à naturalidade a maioria era procedente da região sudeste, seguido pela região nordeste; e por fim seis pacientes eram procedentes de outros países. Com base no sobrenome dos pacientes avaliou-se também a frequência de etnia oriental na casuística estudada, que foi similar nos 2 grupos. O perfil sorológico HBeAg negativo foi o mais frequente nos dois grupos de pacientes, assim como níveis de carga viral abaixo de 2.000 UI/mL. Em relação aos exames bioquímicos foram observadas diferenças estatisticamente significantes nos níveis séricos de AFP (p= 0,0013), FA (p= 0,0003) e GGT (p= 0,005). Dentre os fatores de risco analisados neste estudo, o consumo de amendoim foi o único que apresentou significância estatística (p= 0,003). A região S/pol foi amplificada e sequenciada com sucesso em 58 amostras (28 do grupo 1 e 30 do grupo 2). Entre as 58 amostras analisadas 4 genótipos e 8 subgenótipos do HBV foram identificados, sendo o subgenótipo A1 o mais frequente nos dois grupos. Não se observou diferença estatisticamente significante na distribuição dos subgenótipos entre os dois grupos de pacientes. Na topologia da árvore filogenética construída com sequências do HBV isoladas dos pacientes incluídos neste estudo e sequências disponíveis no GenBank não se observou padrões de agrupamento associados com o perfil clinico do paciente (com e sem CHC). Foram obtidas sequências de boa qualidade da região précore/ core em 44 amostras, sendo 20 amostras do grupo 1 e 24 do grupo 2. Diversas das mutações investigadas foram identificadas na região précore/ core, as quais foram avaliadas estatisticamente para verificar a existência de diferença na frequência das mesmas entre os grupos de pacientes estudados. Entre as mutações identificadas se destacaram com significância estatística as seguintes mutações: T1768A (p= 0,006), a combinação das mutações C1766T + T1768A (p= 0,043) e G1888H (p= 0,05). Na análise de regressão logística simples foi possível identificar que a chance de um paciente do grupo 2 desenvolver CHC aumenta 14,7 vezes na presença de infecção por cepas do HBV com a mutação T1768A, enquanto que a infecção com cepas do HBV que albergam a mutação G1888H reduz tal chance 2,5 vezes / The aim of this study was to evaluate viral factors associated with the progression to hepatocellular carcinoma (HCC) in patients with chronic hepatitis B. For this goal, we characterized HBV subgenotypes, investigated the occurrence of mutations in pre-core/core genes associated with progression to HCC, characterized HBV strains through phylogenetic analyzes and evaluated risk factors associated with HCC. Were included 119 serum samples from patients with chronic HBV infection that were classified in 2 groups: 60 patients with confirmed HCC diagnosis (group 1) and 59 patients with advanced hepatitis B liver disease without the detection of nodular liver lesions and without HCC (group 2). Data about the age, sex and geographic precedence were obtained from medical records. The patients also answered a questionnaire on risk factors for developing HCC. Biochemical, serological and viral load testing were performed in all samples. Moreover, S/polymerase and precore /core regions of HBV DNA were amplified by nested PCR and sequenced by Sanger method. Sequences were analyzed to identify HBV genotypes and subgenotypes and to detect mutations in the precore/core gene. Patient\'s age and sex did not differ between the two groups. Most of the patients came from the Southeast region, followed by the Northeast region; and six patients were from other countries. Based on the patient\'s surname, they were evaluated concerning Eastern ethnicity, which was similar in the 2 groups. Most of the patients included in this study were HBeAg negative and showed viral load bellow 2,000 IU/mL. Concerning the biochemistry assays, statistically significant differences in serum levels of AFP (p = 0.0013), AP (p = 0.0003) and GGT (p = 0.005) were found. Among the risk factors analyzed in this study, peanut consumption was the only one statistically significant (p = 0.003). The S/pol region was successfully amplified and sequenced in 58 samples (28 from Group 1 and 30 from Group 2). Among the 58 samples analyzed, 4 genotypes and 8 subgenotypes were identified, subgenotype A1 was the most frequent in both groups and there was no statistically significant difference in the distribution of them between the two groups. In the phylogenetic tree topology built with HBV sequences isolated from patients included in this study and sequences available in GenBank, it was not observed any clustering associated with the clinical profile of the patients (with or without HCC). Sequences of good quality from pre-core/core region were obtained from 44 samples, 20 from group 1 and 24 from group 2. These sequences were analyzed and several mutations were found among which stood out with statistical significance: T1768A (p = 0.006) C1766T + T1768A (p = 0.043) and G1888H (p = 0.05). In addition to the comparative analysis, the changes were subjected to a simple logistic regression analysis which found that the chance of a patient in group 2 developed HCC increases 14.7 times in the presence of HBV infection strains with the T1768A mutation, while infection with HBV strains harboring the mutation G1888H reduces this chance by 2.5 times