Maternal effects are important mechanisms by which mothers’ may influence the phenotype of their offspring. Females may vary in the resources they can provide during offspring development and understanding the factors responsible for this variation is key to understanding offspring success- in early life as well as later life. Differential allocation has been reported to occur, however how it impacts on offspring and mother’s future reproduction still remains unclear. This is also true for maternal transferred substances like maternally transferred immunity. Contributions to date have been limited to snapshots in time, mean level of transfer and/or limited information regarding other maternal traits. For my thesis, I aim to further the understanding of maternal allocation effects and explore the transfer of maternal antibodies over an immune response of a mother, across multiple breeding attempts and accounting for embryo, maternal and paternal traits. Furthermore, I determine the effect of key male traits on general egg traits along with maternal antibodies. I examine this at the individual level using Chinese painted quail (Coturnix chinensis) who are prolific layers and sexually dimorphic. To date the majority of differential allocation studies have not necessarily addressed the assumptions of differential allocation theory. In Chapter 2 of this thesis I attempt to address some of these assumptions and explore the impact of male characteristics across a number of clutches and find separate effects of initial pairing and subsequent pairings. I found that mothers can create, by differential allocation, clutches of varying size but egg components (egg mass) appears to be largely influenced by initial clutch pairing and not by paternal traits. Furthermore, the effect on egg mass appears to be a secondary effect mediated by females adjusting their condition based on their initial pairing. I demonstrate that unlike general clutch traits (clutch size, egg mass) maternal antibodies are not affected by male characteristics (Chapter 3) carry-over effects of egg size means antibody levels may be influenced throughout life by early experiences. However, maternal immune response may be detrimentally linked to viability of offspring. Whereas maternally transferred antibodies appear to have no relationship with maternal or paternal traits, oocyte yolk antibodies during development were found to correlate with female antibodies up to 48hr prior to lay. In Chapter 4, I examine a neglected area regarding maternal effect- exploring variation between female in their transfer of antibodies. Individual females were highly consistent in the relative level of specific blood antibodies transferred to eggs across different phases of their immune response, across challenge types (bacterial and viral) and that some females consistently transfer significantly more than others. The relative level of circulating antibody transferred was independent of the individual’s overall strength of antibody response and related to the female’s body condition (while the individual’s own antibody responses were not). We found no evidence for any trade-offs between the amount transferred and overall reproductive investment in this chapter. In Chapter 5, I discuss the wider implications of my findings and suggest future research directions.

by Chen Paul. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references (leaves 141-150). / Chapter 1. --- INTRODUCTION --- p.1 / Chapter 1.1 --- Immunomodulation --- p.1 / Chapter 1.2 --- Effector cells mediating anti-tumour immunity --- p.1 / Chapter 1.2.1 --- Cytotoxic T Lymphocytes --- p.3 / Chapter 1.2.2 --- Macrophages --- p.4 / Chapter 1.2.3 --- Natural Killer Cells --- p.5 / Chapter 1.2.4 --- Lymphokine-activated Killer (LAK) --- p.6 / Chapter 1.3 --- Cytokines as immunomodulators in cancer therapy --- p.7 / Chapter 1.3.1 --- Tumour Necrosis Factor-α (TNF-α) --- p.7 / Chapter 1.3.2 --- Interleukin-1 (IL-1) --- p.9 / Chapter 1.3.3 --- Interleukin-2 (IL-2) --- p.9 / Chapter 1.3.4 --- Granulocytes/Macrophages Colony-Stimulating Factors --- p.10 / Chapter 1.4 --- Polysaccharides as potential immunostimulating agents --- p.11 / Chapter 1.5 --- General properties of Klebsiella pneumoniae --- p.12 / Chapter 2. --- AIM AND SCOPE OF THIS DISSERTATION --- p.16 / Chapter 3. --- MATERIALS AND METHODS --- p.18 / Chapter 3.1 --- Materials --- p.18 / Chapter 3.1.1 --- Animals --- p.18 / Chapter 3.1.2 --- Klebsiella pneumoniae K24 --- p.18 / Chapter 3.1.3 --- Cell lines --- p.18 / Chapter 3.1.4 --- "Buffer, Culture media and Chemicals" --- p.19 / Chapter 3.2 --- Methods --- p.27 / Chapter 3.2.1 --- Extraction and Characterization of Klebsiella pneumoniae K24 Capsular Polysaccharide (K24 CPS) --- p.27 / Chapter 3.2.2 --- Assays of Immunomodulatory Activities of K24 CPS on Lymphocytes --- p.30 / Chapter 3.2.3 --- Assays of Immunomodulatory Effect of K24 CPS on Macrophages --- p.34 / Chapter 3.2.4 --- Assays of Anti-Tumour Activities of K24 CPS --- p.39 / Chapter 3.2.5 --- Assays of the Effects of K24 CPS on the Proliferation and Differentiation of Murine Bone Marrow Cells --- p.54 / Chapter 3.2.6 --- Assays of the Immunorestorative Activities of K24 CPS --- p.56 / Chapter 4. --- EXTRACTION AND CHARACTERIZATION OF KLEBSIELLA PNEUMONIAE K24 CAPSULAR POLYSACCHARIDE (K24 CPS) --- p.59 / Chapter 4.1 --- Preparation of Klebsiella pneumoniae K24 CPS Capsular Polysaccharide (K24 CPS) --- p.59 / Chapter 4.2 --- Acetic Acid Treatment of K24 CPS --- p.59 / Chapter 4.3 --- Gel Filtration --- p.59 / Chapter 4.4 --- Carbohydrate and Protein contents of K24 CPS --- p.61 / Chapter 4.5 --- Cytotoxicity Assay using Artemia franciscana (Brine Shrimp) --- p.61 / Chapter 5. --- IMMUNOMODULATORY EFFECTS OF K24 CPS --- p.68 / Chapter 5.1 --- The Effect of K24 CPS in vitro Mitogenic Assay of K24 CPS using Murine Splenocytes --- p.68 / Chapter 5.2 --- The in vivo Mitogenic Effect of K24 CPS on Murine Splenic Lymphocytes --- p.73 / Chapter 5.3 --- The Effect of K24 CPS on the Production of Interleukin-2 (IL-2)-like substance by Murine Splenocytes --- p.73 / Chapter 5.4 --- The effect of K24 CPS on the in vitro Stimulation of Murine Macrophage Nitric Oxide (NO) Production --- p.73 / Chapter 5.5 --- The effect of K24 CPS on the in vitro Stimulation of Macrophage Interleukin-1-like Production --- p.77 / Chapter 5.6 --- The effect of K24 CPS on in vivo Migration of Macrophage --- p.82 / Chapter 5.7 --- The effect of K24 CPS in vitro Stimulation of Macrophage Tumour Necrosis Factor- a (TNF-a) Production --- p.82 / Chapter 6. --- IN VITRO ANTI-TUMOUR EFFECT OF K24 CPS --- p.89 / Chapter 6.1 --- The in vitro Cytostatic effect of K24 CPS on the Suppression of EAT growth --- p.89 / Chapter 6.2 --- The effect of K24 CPS on cell cycle of EAT cells --- p.89 / Chapter 6.3 --- Study of the cytostatic effect of K24 CPS on EAT cells using Western Analysis --- p.93 / Chapter 6.3.1 --- Pattern of Phosphotyrosine Proteins --- p.93 / Chapter 6.3.2 --- Pattern of Phosphoserine Proteins --- p.96 / Chapter 6.3.3 --- Pattern of Phosphothreonine Proteins --- p.96 / Chapter 6.3.4 --- Level of c-fos --- p.99 / Chapter 6.3.5 --- Level of c-jun --- p.99 / Chapter 6.3.6 --- Level of c-myc --- p.102 / Chapter 7. --- THE IN VIVO ANTI-TUMOUR ACTIVITIES OF K24 CPS --- p.103 / Chapter 7.1 --- The effect of K24 CPS on the In vivo Suppression of EAT growth --- p.103 / Chapter 7.2 --- The effect of K24 CPS on the survival of EAT-bearing mice --- p.103 / Chapter 7.3 --- The effect of K24 CPS on the in vivo induction of Natural Killer (NK) Cell Cytotoxicity --- p.111 / Chapter 7.4 --- The effect of K24 CPS in vitro induction of Lymphokine-activated Killer (LAK) Cell Cytotoxicity --- p.111 / Chapter 7.5 --- The effect of K24 CPS on the in vivo Induction of Lymphokine-activated Killer (LAK) Cell Cytotoxicity --- p.114 / Chapter 7.6 --- The effect of K24 CPS on the endogenous production of TNF-α --- p.114 / Chapter 7.7 --- The effect of K24 CPS on the endogenous TNF-α production and EAT growthin vivo --- p.117 / Chapter 8. --- THE IMMUNORESTORATIVE ACTIVITIES OF K24 CPS --- p.122 / Chapter 8.1 --- The in vivo Immunorestorative Activities of K24 CPS in EAT-bearing Mice --- p.122 / Chapter 8.2 --- The in vitro Immunorestorative Activities of K24 CPS in Mice bearing 10-day-old- EAT --- p.122 / Chapter 9. --- THE EFFECT OF K24 CPS IN VITRO INDUCTION OF MURINE BONE MARROW CELLS PROLIFERATION AND DIFFERENTIATION --- p.126 / Chapter 9.1 --- The effect of K24 CPS in vitro induction of Murine Bone Marrow Cells Proliferation --- p.126 / Chapter 9.2 --- The effect of K24 CPS in vitro induction of Murine Bone Marrow Cells Differentiation --- p.126 / Chapter 10. --- CONCLUSIONS AND FUTURE PERSPECTIVES --- p.135 / Chapter 11. --- BIBLIOGRAPHY --- p.141

As modificações das lipoproteínas de baixa densidade (LDL) são uma etapa essencial na aterogênese pois acarretam a geração de LDL eletronegativa [LDL(-)] que apresenta propriedades quimiotática, citotóxica, imunogênica e pró-inflamatória. O objetivo deste trabalho foi a produção de hibridomas secretores de anticorpos monoclonais anti-LDL(-), a clonagem dos genes que codificam para as cadeias variáveis destes anticorpos, e sua expressão como fragmentos de anticorpo de cadeia única (scFv). A LDL(-) isolada de plasma humano foi utilizada como antígeno para imunização de camundongos BALB/c. Após triagem dos clones, dois anticorpos monoclonais foram obtidos baseados em sua reatividade pela LDL( -) e não pela LDL nativa: 1A3H2 (1A3) e 2C7D5F10 (2C7). Os cDNAs codificante para a cadeia pesada (VH) e cadeia leve (VL), de ambos os anticorpos, foram obtidos por meio de RT-PCR utilizando bibliotecas de oligonucleotídeos que reconhecem todas os genes de domínios variáveis das famílias de VH e VL murinas. Os genes da VH e VL obtidos foram clonados no vetor pGEM-T Easy (Promega®) e suas seqüências determinadas. A VH do anti-LDL(-) 1A3 pertence família J558.84 e fragmento gênico JH2, enquanto sua VL pertence a família 8.24 e fragmento gênico Jk5. A VH do anti¬-LDL(-) 2C7 pertence a família Vmu 3.2 (J558) e fragmento gênico JH4, enquanto sua VL pertence a família 8.24 e fragmento gênico Jk5. A partir disso, oligonucleotídeos sintéticos foram sintetizados a fim de clonar estes segmentos gênicos no vetor pPlgLE de expressão em Pichia pastoris. Foram realizadas três construções: o scFv 1A3, scFV 2C7 e um scFv híbrido (VH do 1A3 e VL do 2C7). Das três construções obtidas, conseguimos expressar o scFv do anti-LDL 2C7D5F10 que demonstrou ser capaz de reconhecer o antígeno. A proteína recombinante expressa tem grande potencial de ser usada no diagnóstico clínico incluindo imunoensaios in vitro e como reagentes para exames que envolvam a obtenção e análise de imagens. / Oxidative modification of low-density lipoproteins (LDL) is an essential step in atherogenesis, generating electronegative LDL [LDL(-)], which has chemotactic cytotoxic, immunogenic and proinflammatory properties. The aim of this study was the generation of anti-LDL(-) mAbs, the cloning of the genes that code for their variable domains and their expression as single-chain Fv (scFv). LDL(-) was isolated from human blood plasma and used as an antigen for immunization of Balb/c mice. Upon screening, two different mAbs were selected based on their ability to recognize LDL(-) and not native LDL: 1A3H2 (1A3) e 2C705F10 (2C7). The cDNAs that code for VH and VL were obtained by RT-PCR using specific immunoglobulin primer libraries wich recognize all VH and VL murine families. The VH and VL genes were cloned in pGEM-T Easy (Promega®) and sequenced. The anti-LDL(-) 1A3 uses a VH segment from J558.84 and a JH2 segment, while VL uses a 8.24/Jk5 segments. The anti-LDL(-) 2C7 uses a VH segment from Vmu 3.2 (J558) and a JH4 segment, while VL uses a 8.24/Jk5 segments. Oligonucleotides were synthetized and those gene segments were cloned in pPIGLE a Pichia pastoris immunoglobulin expression vector. We obtained three scFv constructions: scFV 1A3, scFv 2C7 and a husk hybrid, harboring 1A3 VH and 2C7 VL. Among those, we expressed the scFv anti¬-LDL(-) 2C7 that are able to recognize the antigen. The recombinant protein has a great potential for clinicai diagnostic applications, including in vitro immunoassays and as imaging reagents.

L'évolution par sélection naturelle se compose d'une succession de trois étapes : mutations, sélection et prolifération. Nous nous intéressons à la description et à la caractérisation du résultat d'une étape de sélection dans une population composée de nombreux variants. Après sélection, cette population va être dominée par les quelques meilleurs variants, ceux qui ont la plus grande capacité à être sélectionnés, ou plus grande « sélectivité ». Nous posons la question suivante : comment est distribuée la sélectivité des meilleurs variants dans la population? La théorie des valeurs extrêmes, qui caractérise les queues extrêmes des distributions de probabilités en terme de 3 classes d'universalités, a été proposée pour répondre à cette question. Pour tester cette proposition et identifier les classes d'universalités rencontrées dans ce genre de problème, nous avons procédé à une sélection quantitative de banques composées de $10^5$ variants d'anticorps grâce à la technique du phage display. Les données obtenues par séquençage à haut débit du résultat de la sélection de nos banques nous permettent d'ajuster la distribution de sélectivités obtenue sur plus de deux décades. / Evolution by natural selection involves the succession of three steps: mutations, selection and proliferation. We are interested in describing and characterizing the result of selection over a population of many variants. After selection, this population will be dominated by the few best variants, with highest propensity to be selected, or highest “selectivity”. We ask the following question: how is the selectivity of the best variants distributed in the population? Extreme value theory, which characterizes the extreme tail of probability distributions in terms of a few universality class, has been proposed to describe it. To test this proposition and identify the relevant universality class, we performed quantitative in vitro experimental selections of libraries of > $10^5$ antibodies using the technique of phage display. Data obtained by high-throughput sequencing allows us to fit the selectivity distribution over more than two decades. In most experiments, the results show a striking power law for the selectivity distribution of the top antibodies, consistent with extreme value theory.

Next generation monoclonal antibodies (mAbs) are unique in that they are specifically designed to enhance their mechanisms of action, primarily complement fixation and antibody-dependent cellular cytotoxicity (ADCC). Recent studies suggest that complement-fixing properties of a mAb can counter its ability to activate NK cells and mediate ADCC. GA101, a third generation (type II anti-CD20) mAb, and rituximab-MAGE (glyco-engineered type I mAb) show enhanced ADCC and direct cell killing; while ofatumumab, a second generation anti-CD20 mAb, shows enhanced complement-mediated cytotoxicity (CMC). These studies set out to determine the primary mechanisms of actions of these various mAbs, and compare the effect of complement on their ability to activate NK cells and mediate ADCC or CMC. We also studied the efficiency of rituximab vs. rituximab-MAGE to deplete B-cells in vivo in mice expressing human transgenic CD20. In vitro, rituximab and ofatumumab fixed more complement and mediated a greater degree of CMC, than GA101 and rituximab-MAGE. Additionally, complement inhibited the ability of both rituximab and ofatumumab to bind to and activate NK cells, whereas, addition of complement to GA101 or rituximab-MAGE did not affect their NK cell activating ability. Complement also blocked rituximab-induced NK-cell mediated ADCC, but not GA101-induced NK-cell mediated ADCC. Finally, GA101 and rituximab-MAGE depleted a higher percentage of B cells in whole blood compared to rituximab and ofatumumab, whereas rituximab-MAGE depleted fewer B cells, in vivo, in a complement-dependent fashion. We conclude from these studies that there are significant differences among these antibodies and that the ability of a given antibody to mediate CMC and complement fixation correlates with the ability of complement to block the interaction between the antibody and NK cells.

Cecal coccidiosis, caused by the protozoan Eimeria tenella, may manifest as a devastating disease in young chickens and result in substantial economic loss for producers. The parasite progresses through a complex life cycle, exhibiting both asexual and sexual (gamont) stages of development. The purpose of this study was to produce a panel of monoclonal antibodies (MoAbs) against epitopes contained on surface antigens (Ags) of the gamonts of E. tenella with the intent of blocking the fertilization process. Gamonts were harvested from infected ceca, partially purified by differential centrifugation throught a discontinuous 5050% Percoll density gradient and used as a source of Ag for the production of MoAbs. Immune spleen cells collected from Robertsonian (strain RBF/Dn) mice were fused with FOX-NY myeloma cells and the resultant MoAb-secreting hybridomas screened by an indirect immunofluorescent antibody test (IFAT). A panel of 13 MoAbs (1 IgG2a and 12 IgG1) was selected form a bank of 94 hybridomas. The Ag specificity of the MoAbs was determined by processing infected cecal mucosa smears and noninfected and infected cecal cross sections through the IFAT procedures. It is likely that the panel of 13 MoAbs exhibits specificity for Ags on or in the macrogamonts of E. tenella. Specificity may not be restricted to macrogamonts, however, since common epitopes make exist between microgamonts and microgamonts. In vitro studies were begun to determine the ability of the MoAbs to inhibit gamont fertilization. Merozoites were inoculated into a monolayer of chick kidney cells, and in vitro development of the parasite was monitored. Data were insufficient for statistical analysis, since the merozoites did not develop to the oocyst stage.

Foot-and-mouth disease (FMD) is one of the most contagious infectious diseases of domestic and wild cloven-hoofed animals, particular in cattle, sheep, pigs, goats and domestic buffalo, as well as wild ruminants such as deer. In Taiwan, there was a severe outbreak of FMD after more than 60 years freedom from the disease. The virus strain, O Taiwan 97 from the March 1997 outbreak of FMD in Taiwan, however, has been shown to have a species-specific adaptation to pigs. Although there are 7 distinct serotypes of FMD found in different regions of the world, this study focuses on the pig-adapted type O strain of FMD. After the FMD outbreak commenced in Taiwan, the spread of disease was very rapid and the whole of the western parts of Taiwan was affected within a few days after the diagnosis of FMD was confirmed. In some situations airborne transmission of FMD virus was suspected and it was speculated that this was the explanation for such rapid spread in Taiwan. Therefore, studies were conducted to investigate the transmissibility of O Taiwan/97 FMDV to susceptible pigs by direct and indirect spread including airborne spread in an enclosed animal house. This study showed that pigs in direct contact with challenged pigs became infected but none of the close-contact pigs became infected. These experiments clearly demonstrated that the pig adapted strain O Taiwan/97 was only efficiently transmitted by direct contact. This indicates that effective control against future outbreaks of pig adapted FMDV strains could be achieved by restriction of pig movement and stamping out if the outbreak has been detected in the early stages and prior to the movements of pigs from the infected premises. The measures used to control the Taiwanese FMD outbreak in 1997 were initially the slaughter of whole herds in the infected premises. However, with the rapid spread and large numbers of cases, the decision was taken to use universal compulsory vaccination of pig herds to control the outbreak when sufficient supply of vaccines was organized. Type O FMD vaccines were imported from a number of major FMD vaccine manufactures from around the world. Initially, vaccine efficacy for the imported vaccines was tested by measurement of neutralizing antibody titers in vaccinated pigs. To establish the relationship between serum neutralizing titers and protection from foot and mouth disease in pigs after vaccination, challenge studies were conducted with O/Taiwan/97 FMD in vaccinated pigs. Additionally, antibody responses to structural (neutralizing antibody) and non-structural proteins (NSP) were evaluated in vaccinated pig herds after primary and secondary vaccination in herds infected before and after vaccination. In order to be able to monitor the circulation of virus in vaccinated pig populations, valid diagnostic kits based on the detection of antibody against NSP were required. These tests needed to be evaluated against pig sera derived from challenge studies and natural FMD outbreaks. Three commercially available ELISAs (Cedi, UBI and Checkit), which were available to differentiate infected from vaccinated pigs, were tested and results showed that the Cedi test had the optimal sensitivity and specificity for pig adapted type O FMD testing. This test was used to retrospectively evaluate the sera collected from infected and non-infected pig herds collected sequentially in the year after the 1997 FMD outbreak in Taiwan. These studies also showed that the early vaccines used, stimulated NSP antibody production in swine herds that were vaccinated but not infected. This resulted in the requirement for purified FMD vaccines to be used when monitoring programs for FMD infection by NSP testing were in place. In these studies, it was also demonstrated that the purified FMD vaccines used later in the control program did not induce NSP antibody after multiple double dosage to pigs. Although clinical FMD appeared to be successfully controlled with vaccination program in Taiwan it was essential for the eradication plan to maintain active surveillance for NSP reactors in the pig population. The UBI and Cedi NSP kits were applied as screening and confirmatory tests, respectively, to pig sera collected in auction markets distributed around Taiwan to monitor for evidence of the circulation of FMD virus. Herds with positive reactors were followed-up by clinical inspection and 15 sera from suspected herds were further sampled. Negative results were obtained from all these investigation. With the absence of clinical outbreaks and the lack of evidence of FMDV circulation in the field from the NSP reactor surveillance, the Taiwanese government has progressed the eradication plan to a progressive cessation of vaccination, commencing with banning of vaccination on one isolated island in December 2006. The absence of outbreaks on that island, paved the way for further cessation of FMD vaccination in Taiwan from July 2008.

An outline of the work contained in this thesis is presented. The first chapter is a critical review of the literature pertaining to the pathophysiological mechanisms operational with regards to the antiphospholipid syndrome (APS). The syndrome is characterised by venous and arterial thrombosis, and recurrent fetal loss, in association with the persistent presence of antibodies targeting the main autoantigen beta 2-glycoprotein I (β2GPI). The second chapter reviews the literature delineating the diverse physiological functions of β2GPI, and then relates them to its role in our current understanding of the pathophysiology of APS. The third chapter presents a critical review of the evidence base for the diagnosis and management of APS. The fourth chapter describes the interaction between β2GPI and the glycoprotein Ib alpha (GPIbα) subunit of the platelet receptor GPIb-IX-V. GPIbα is an important platelet adhesion receptor, which mediates multiple additional functions on the platelet surface, including binding coagulation factor XI (FXI). The implication of the interaction between β2GPI and GPIbα on platelet activation and the release of thromboxane in the presence of anti-β2GPI antibodies is explored, as well as the intracellular pathways via which this activation occurs. The relevance of these findings to understanding APS pathogenesis, in particular thrombosis, is discussed. The fifth chapter delineates the interaction between the fifth domain of β2GPI and FXI and its activated form factor XIa (FXIa). The ability of FXIa to cleave β2GPI between lysine (Lys) 317 and threonine (Thr) 318, and modulate its function is reported. The sixth chapter describes the ability of β2GPI to inhibit FXIa autoproteolytic hydrolysis at the specific FXIa residues arginine (Arg) 507, Arg532 and Lys539. This interaction with β2GPI stabilizes FXIa activity over time, and leads to enhanced FXIa mediated fibrin formation. This is a novel physiological function of β2GPI with important implications. Recent epidemiological studies by others have emphasized the critical role of FXIa in pathological thrombus propagation. The seventh chapter defines the relevance of the FXIa residues Arg507, Arg532 and Lys539 to FXIa mediated inactivation by the main FXIa inhibitor Protease Nexin 2 (PN2), and by Antithrombin III (ATIII). Insights into future directions for research are presented and discussed within each individual chapter.

Classical immunoglobulin transgenic (Ig-Tg) mouse models such as the MD4 anti-hen egg lysozyme (-HEL) Ig-Tg line have been used extensively to study B cell responses in tolerance and immunity. This thesis describes a new generation of gene-targeted mice (designated SWHEL mice) whereby the VH10 Ig variable gene encoding the HyHEL-10 specificity of the original anti-HEL Ig-Tg mouse was targeted to the Ig heavy chain locus. B cells in the SWHEL mouse are therefore capable of undergoing class switch recombination (CSR) and somatic hypermutation (SHM), representing a major advance on the original MD4 mouse model. SWHEL mice were found to not only contain a large population of HEL-specific (HEL+) B cells but also a significant population of non-HEL-binding (HEL-) B cells generated by VH gene replacement. HEL+ SWHEL B cells were found to belong to the B2 lineage and displayed high levels of surface IgM. Nevertheless, they matured normally and colonised the primary B cell follicle and marginal zone (MZ) of the spleen. The SWHEL model thus provided an opportunity to re-examine some of the original observations made in the MD4 system and also to extend these observations, particularly with regard to the regulation of CSR by self-reactive B cells. As expected, analysis of SWHEL B cells exposed to high avidity membrane-bound HEL revealed that they underwent clonal deletion in the bone marrow (BM). More interestingly, analysis of HEL+ B cells exposed to low avidity soluble HEL revealed that they were able to emigrate from the BM to the spleen as anergic B cells. However, unlike anergic MD4 B cells, anergic SWHEL B cells were reduced in frequency, displayed an immature B cell phenotype, were excluded from the follicle and had a reduced lifespan. Direct measurement of B cell antigen receptor (BCR) occupancy by HEL and the frequency of HEL- competitor B cells was combined with mixed BM irradiation chimeras to demonstrate unequivocally that the difference in phenotype and fate of HEL+ B cells in the two systems was due solely to competition from HEL- B cells. In addition, the SWHEL model of B cell self-tolerance was used to show that while self-reactive B cells were hypo-responsive to BCR stimulation, BCR-independent signals delivered via anti-CD40 plus IL-4 or lipopolysaccharide could trigger them to undergo CSR and secretion of potentially pathogenic isotype-switched autoantibodies. Finally, the SWHEL model was used to study the responses of adoptively transferred follicular (Fo) and MZ B cells to in vivo activation with HEL conjugated to sheep red blood cells (HEL-SRBC). These studies revealed that both HEL+ MZ and Fo B cells were capable of mounting a robust T cell-dependent IgG1 antibody response to HEL-SRBC. However, HEL+ MZ B cells did not efficiently localise to the T cell-B cell border following antigen engagement and preferentially migrated to the bridging channels and red pulp. In contrast, HEL+ Fo B cells rapidly localised to the T cell-B cell border and subsequently colonised numerous germinal centres. As a result, the rate and pattern of SHM by HEL+ Fo and MZ B cells was shown to be distinct, with preferential targeting of mutations to the second complementarity-determining region in the former and to the second framework region in the latter. Together these data indicate illustrate the value of the SWHEL model and its potential to greatly advance the current understanding of B cell responses in tolerance and immunity.

<p>Targeted radionuclide therapy (TRT) holds great promise for the treatment of cancer. In TRT, radioactive nuclides are delivered specifically to tumours by molecules that recognise and bind to structures overexpressed by, or specific to, cancer cells. Human epidermal growth factor receptor like protein 2 (HER-2) is an oncogene product overexpressed in e.g. urological, breast, or ovarian cancers that have been correlated to poor prognosis and resistance to hormonal therapy. There is also evidence that tumour cells retain their HER-2 overexpression in metastases.</p><p>Trastuzumab and pertuzumab are two humanised monoclonal antibodies targeting different parts of HER-2. This thesis describes the radiolabelling of these antibodies for use in TRT and diagnostics. The thesis also investigates possible methods for modifying uptake and retention of radioactivity delivered with antibodies binding to HER-2. Modification of the cellular retention of ¹²⁵I by using polyhedral boron anion based linker molecules (DABI and NBI) is investigated, and it is shown that linking ¹²⁵I to trastuzumab using DABI increases cellular accumulation of radioactivity by 33%. It is also shown that trastuzumab can be efficiently coupled to the positron emitter ⁷⁶Br by using NBI. Furthermore, it is shown that cellular uptake of ¹²⁵I can be modified by stimulating EGFR (HER-1) with EGF.</p><p>When labelled with the alpha emitter ²¹¹At, trastuzumab could specifically kill cells in vitro. This cell killing effect could be prevented by saturating the receptors of the target cells with non-radiolabelled trastuzumab.</p><p>Pertuzumab was radiolabelled with the low energy beta emitter ¹⁷⁷Lu without losing affinity or immunocompetence. [¹⁷⁷Lu]pertuzumab was specific to HER-2 in vitro and in vivo. This targeting conjugate was shown to increase median time to tumour progression in mice bearing xenografts of the radioresistant SKOV-3 cell line. </p><p>In conclusion, antibodies against HER-2, especially pertuzumab radiolabelled with ¹⁷⁷Lu, show promise as TRT agents.</p>