Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.

Thesis (Ph.D. in Immunology) -- University of Colorado Denver, 2008. / Typescript. Includes bibliographical references (leaves 122-129). Free to UCD Anschutz Medical Campus. Online version available via ProQuest Digital Dissertations;

Thesis (Ph.D. in Immunology) -- University of Colorado Denver, 2008. / Typescript. Includes bibliographical references (leaves 153-162). Free to UCD Anschutz Medical Campus. Online version available via ProQuest Digital Dissertations;

Thesis (Ph. D.)--University of Alabama at Birmingham, 2008. / Title from first page of PDF file (viewed Feb. 12, 2009). Includes bibliographical references.

Le traitement du lymphome B non hodgkinien (NHL) est généralement basé sur la combinaison d’un anticorps monoclonal anti-CD20, le rituximab, et de la chimiothérapie. Cependant, de nombreux patients deviennent réfractaires au ciblage du récepteur CD20. Dans cette thèse, l’effet d’un nouvel anticorps monoclonal anti-CD37 conjugué au Luthétium-177 (177Lu-lilotomab, Betalutin®) est étudié dans des modèles précliniques de lymphome non hodgkinien et comparé au rituximab radiomarqué au luthétium-177 (177Lu-rituximab). Nous avons développé une approche radiobiologique qui distingue les effets cytotoxiques dus à l’anticorps monoclonal et dus aux rayonnements ionisants dans des lignées cellulaires de lymphome humain. Cette méthode a permis de montrer qu’in vitro, le rituximab et le 177Lu-rituximab étaient plus cytotoxiques que le lilotomab et le 177Lu-lilotomab dans la lignée cellulaire radiorésistante Ramos (modèle du lymphome de Burkitt). Inversement, le 177Lu-lilotomab et le 177Lu-rituximab ont montré la même cytotoxicité dans la lignée cellulaire radiosensible DOHH2 (modèle de lymphome folliculaire transformé). Leur cytotoxicité était plus faible dans la lignée cellulaire Rec-1 (modèle du lymphome du manteau) que dans les cellules DOHH2. Ces résultats ont été confirmés in vivo sur des souris traitées par injection intraveineuse après xénogreffe sous-cutanée de cellules Ramos ou DOHH2. Le 177Lu-lilotomab et le 177Lu-rituximab ont montré la même efficacité thérapeutique chez les souris xénogreffées avec les cellules radiosensibles DOHH2, alors que le lilotomab non radiomarqué était moins efficace que le rituximab. Inversement, chez les souris xénogreffées avec les cellules radiorésistantes Ramos, la plus faible efficacité du 177Lu-lilotomab comparé au 177Lu-rituximab peut seulement être compensée par une augmentation de dose absorbée à la tumeur par le 177Lu-lilotomab. Mécanistiquement, la réponse cellulaire des tumeurs aux radiations dépend de la réponse apoptotique des cellules et de la réduction de l’arrêt en G2/M du cycle cellulaire via les phosphorylations médiées par WEE-1 et MYT-1 de la kinase dépendante des cyclines-1 (CDK1) sur la tyrosine 15 et thréonine 14. Ces résultats indiquent que l’interaction synergistique entre les effets cytotoxiciques du 177Lu et du lilotomab dans les tumeurs montrant une réduction des niveaux de phosphorylations de CDK1 peut compenser le manque d’efficacité thérapeutique du lilotomab comparé au rituximab. / Currently, B-cell Non-Hodgkin Lymphoma (NHL) treatment relies on the anti-CD20 antibody rituximab and chemotherapy. However, some patients become refractory to this therapy. Here, the effect of the novel anti-CD37 antibody-radionuclide conjugate 177Lu-lilotomab (Betalutin®) was investigated in NHL preclinical models and compared to 177Lu-labeled rituximab (anti-CD20 antibody). We developed a radiobiological approach that discriminates between the cytotoxic effects of unlabeled antibodies and of radiation in human lymphoma cell lines. This method allowed showing that in vitro, rituximab and 177Lu-rituximab were more cytotoxic than lilotomab and 177Lu-lilotomab in the radioresistant Ramos Burkitt’s lymphoma cell line. Conversely, 177Lu-rituximab and 177Lu-lilotomab had similar efficacy in the radiosensitive follicular lymphoma DOHH2 cell line. Their cytotoxicity was lower in mantle cell lymphoma Rec-1 cells that are less radiosensitive than DOHH2 cells. These results were confirmed in vivo in mice treated by intravenous injection of these antibodies after subcutaneous xenografts of Ramos or DOHH2 cells. 177Lu-lilotomab and 177Lu-rituximab showed the same therapeutic efficacy in mice xenografted with radiosensitive DOHH2 cells, although unlabeled lilotomab was less efficient than rituximab. Conversely, in mice xenografted with radioresistant Ramos cells, the lower efficacy of 177Lu-lilotomab compared with 177Lu-rituximab could only be compensated by increasing 177Lu-lilotomab tumor absorbed dose. Mechanistically, the tumor cell response to radiation depended on the cell apoptotic response and reduction of G2/M cell cycle arrest through WEE-1 and MYT1-mediated phosphorylation of cyclin-dependent kinase-1 (CDK1) at tyrosine 15 and threonine 14. These results indicate that the synergistic interaction between 177Lu irradiation and lilotomab cytotoxic effects in tumors with reduced CDK1 phosphorylation levels can correct the lower therapeutic efficacy of lilotomab compared with rituximab.

abstract: The Philadelphia chromosome in humans, is on oncogenic translocation between chromosomes 9 and 22 that gives rise to the fusion protein BCR-Abl. This protein is constitutively active resulting in rapid and uncontrolled cell growth in affected cells. The BCR-Abl protein is the hallmark feature of chronic myeloid leukemia (CML) and is seen in Philadelphia-positive (Ph+) acute lymphoblastic leukemia (ALL) cases. Currently, the first line of treatment is the Abl specific inhibitor Imatinib. Some patients will, however, develop resistance to Imatinib. Research has shown how transformation of progenitor B cells with v-Abl, an oncogene expressed by the Abelson murine leukemia virus, causes rapid proliferation, prevents further differentiation and produces a potentially malignant transformation. We have used progenitor B cells transformed with a temperature-sensitive form of the v-Abl protein that allows us to inactivate or re-activate v-Abl by shifting the incubation temperature. We are trying to use this line as a model to study both the progression from pre-malignancy to malignancy in CML and Imatinib resistance in Ph+ ALL and CML. These progenitor B cells, once v-Abl is reactivated, in most cases, will not return to their natural cell cycle. In this they resemble Ph+ ALL and CML under Imatinib treatment. With some manipulation these cells can break this prolonged G1 arrested phenotype and become a malignant cell line and resistant to Imatinib treatment. Cellular senescence can be a complicated process requiring inter-play between a variety of players. It serves as an alternate option to apoptosis, in that the cell loses proliferative potential, but does not die. Treatment with some cancer therapeutics will induce senescence in some cancers. Such is the case with Imatinib treatment of CML and Ph+ ALL. By using the S9 cell line we have been able to explore the possible routes for breaking of prolonged G1 arrest in these Ph+ leukemias. We inhibited the DNA damage sensor protein ataxia telangiectasia mutated (ATM) and found that prolonged G1 arrest in our S9 cells was broken. While previous research has suggested that the DNA damage sensor protein ataxia-telangiectasia mutated (ATM) has little impact in CML, our research indicates that ATM may play a role in either senescence induction or release. / Dissertation/Thesis / M.S. Microbiology 2011

An optimal antibody response to a thymus-dependent antigen requires cooperation between the B cell and an antigen-specific helper T cell. Major histocompatibility complex restriction of this interaction implies that the helper T cell recognizes antigen on the B cell surface in the context of MHC molecules, and that the antigen-specific B cell gets help by acting as an antigen presenting cell for the helper T cell. However, a number of studies have shown that normal resting B cells are ineffective as antigen presenting cells, implying that the B cell must leave the resting state before it can interact specifically with a helper T cell. On the contrary, other studies, including those using rabbit Ig as antigen, and rabbit globulin-specific mouse T cell lines and hybridomas, show that certain T cell lines can be efficiently stimulated by normal resting B cells. One possibility I considered was that small B cells are unable to process antigens, and that the rabbit Ig-specific T cell lines used above recognize native antigen on the B cell surface. In the majority of cases, experiments with B cell lines and macrophages have shown that antigen presentation requires antigen processing, a sequence of events which includes: internalization of antigen into an acid compartment, denaturation or digestion of antigen into fragments, and the return of processed antigen to the cell surface where it can then be recognized by the T cell in the context of class II molecules of the MHC. The experiments reported here show that the rabbit Ig-specific T cell lines do require an antigen processing step, and that small resting B cells, like other antigen presenting cells, process antigen before presenting it to T cells. Specifically, I show that an incubation of 2-8 hours is required after the antigen pulse before antigen presentation becomes resistant to fixation or irradiation. Shortly after the pulse, the antigen enters a pronase resistant compartment. Chloroquine, which raises the pH of endocytic vesicles, inhibits presentation. In addition, a large excess of antibody to native antigen fails to block presentation of antigen after a 2-8 hour incubation. Also, although membrane Ig, the antigen receptor on the B cell, is required for efficient presentation of antigen at low concentrations, antigen is no longer associated with the B cell receptor at the time of presentation to the T cell. Modulation of membrane Ig by anti-Ig blocks presentation before but not after the antigen pulse.

Introdução: as doenças linfoproliferativas de células B maduras correspondem a cerca de 80% das neoplasias linfoides, são caracterizadas pela proliferação clonal de uma célula B precursora em diferentes estágios de diferenciação. A semelhança imunofenotípica a um dado estágio maturativo é relevante para o diagnóstico diferencial através da imunofenotipagem por citometria de fluxo, embora a sobreposição de expressões possa dificultar a identificação correta de cada linfoproliferação. Alguns marcadores são pouco conhecidos nas diferentes linfoproliferações B e há pouca literatura analisando os dados quantitativamente, sendo grande parte qualitativa. Objetivos: este trabalho avalia a expressão quantitativa em intensidade de fluorescência média (IFM) dos anticorpos CD200, CD43, CD52 e CD123 no diagnóstico diferencial das doenças linfoproliferativas B crônicas. Métodos: estudo transversal, com 124 amostras de pacientes em investigação diagnóstica de doenças linfoproliferativas que realizaram imunofenotipagem em um centro de referência em neoplasias hematológicas no período de outubro de 2014 a junho de 2015. Foram analisadas as IFMs de cada marcador nas onze diferentes doenças diagnosticadas. Resultados: as neoplasias dos 124 pacientes analisados foram: 81 leucemias linfocíticas crônicas (LLC), 17 linfomas de zona marginal (LZM), 9 linfomas linfoplasmocíticos (LLPL), 6 linfomas do manto (LM), 2 tricoleucemias (TRL), 2 tricoleucemias variantes (TRLv), 5 linfomas foliculares (LF), 1 linfoma de Burkitt e 1 linfoma difuso de grandes células B (LDGCB). A expressão mediana do CD200 foi de 46,8 (intervalo: 1,5-334). A expressão mediana de CD200 foi maior na TRL (incluindo a TRLv) e na LLC (85 e 61,2, respectivamente). A expressão de IFM do CD200 na TRLv diferiu quando comparado à TRL na sua forma clássica (mediana: 36,1 versus 220,3). A mesma diferença foi observada na expressão do CD123 quando comparada a TRL à TRLv. Verificamos, que casos de LZM demonstraram IFM medianas de CD43 de 7,1 (intervalo: 1,1-106), em comparação a casos de LM e LLC, nos quais as medianas de IFM do CD43 foram 90 e 176, respectivamente. A comparação da intensidade de CD52 entre amostras demostrou diferença estatisticamente significativa entre LLC e LZM com medianas de IFM de 775,5 versus 1297,0 (P=0,04). Conclusões: nossos resultados sugerem que a citometria de fluxo quantitativa desses marcadores pode ser uma ferramenta adicional útil na identificação de alguns tipos de DLPCBs. / Background: lymphoproliferative disorders of mature B cells account for about 80% of the lymphoid malignancies. They are characterized by the clonal proliferation of a B cell precursor at different stages of differentiation. The similarity of a given phenotypical maturation stage is relevant for the differential diagnosis by immunophenotyping, however overlap in cell morphology and immunologic features may difficult the correct identification of each pathology. Some markers are not well known in different B lymphoproliferative neoplasms and there is little literature analyzing the data quantitatively. Objectives: this study evaluated the expression of CD200, CD43, CD52 and CD123 by flow cytometry on B-cell chronic lymphoproliferative disorders (BCLDs) differential diagnosis. Methods: cross-sectional study, of 124 samples from patients for diagnostic investigation of lymphoproliferative disorders who underwent immunophenotyping in a referral center for hematologic malignancies from October 2014 to June 2015. MFIs were analyzed for each marker in eleven different diagnosed pathologies. Results: the diseases of the 124 patients investigated comprised: 81 chronic lymphocytic leukemia (CLL), 17 marginal zone lymphoma (MZL), 9 lymphoplasmacytic lymphoma (LPL), 6 mantle cell lymphoma (MCL), 2 hairy cell leukemia (HCL), 2 hairy cell leukemia variant (HCLv), 5 folicular lymphoma (FL), 1 Burkitt lymphoma (BL) e 1 diffuse large B cell lymphoma (DLBCL). The CD200 median MFI expression was 46,8 (range: 1,5-334). CD200 was higher in HCL (including HCLv) and CLL cells (85 and 61,2 respectively). HCLv difference in CD200 MFI, when compared to classical HCL (median 36,1 versus 220,3). The same difference in CD123 expression was observed when comparing HCL versus HCLv. We found that cases of MZL exhibited CD43 median MFI of 7,1 (range: 1,1-106), in contrast to cases of MCL and CLL, which had median MFIs for CD43 of 90 and 176, respectively. The comparison of CD52 intensity between CLL and MZL samples showed statistically significant difference with a median MFI of 777,5 versus 1297,0 (P=0,04). Conclusion: our results suggest that quantitative flow cytometry of these markers may be a useful additional tool to better identify some types of BCLDs.

Dans le système immunitaire, l’activation des cellules B nécessite la reconnaissance spécifique par les récepteurs membranaires des cellules B des antigènes portés par cellules présentatrices d’antigènes (macrophages, cellules dendritiques, …). Cette reconnaissance se traduit par une accumulation de protéines adhésives constituant une structure moléculaire appelée synapse immunologique, à partir de laquelle sont extraits les antigènes. Les mécanismes biologiques impliqués dans l’extraction d’antigènes par les cellules B sont encore mal connus. Dans notre étude, nous proposons d’utiliser des gouttes d’huile dont la surface est fonctionnalisée par des anticorps, comme substrat pour l’activation des cellules B. Ces gouttes présentent l’intérêt de posséder une interface liquide et d'être déformables (mesure de forces possible). Afin de mettre en contact les gouttes fonctionnalisées avec les cellules B, nous avons fabriqué un réseau de pièges ayant la forme d’un U répartis dans une chambre microfluidique. La forme de cette chambre a été optimisée de manière à garantir un remplissage efficace des pièges. Le dispositif expérimental mis au point permet de mettre en contact une goutte fonctionnalisée par des anticorps et une cellule B dans plusieurs pièges en parallèle, et d’observer l’évolution du contact dans le temps par microscopie. Nous avons observé que le contact goutte/cellule induisait une accumulation d’anticorps greffés à la goutte au niveau de la zone de contact. La cinétique d’accumulation est mesurée. Des observations en fluorescence des lysosomes des cellules B montrent une polarisation vers la zone de contact, suggérant une réponse de la part de la cellule. / In the immune system, B cell activation is triggered by the specific binding of the B cell receptors with the antigens present on antigen-presenting cells like macrophage, dendritic cells, ... This recognition leads to an accumulation of adhesive proteins at the contact. This molecular structure is called immune synapse, from which the antigens are extracted by the B cell. The precise biological mechanisms implied in the extraction of antigens are still unknown. In our work, we propose to use antibody-coated oil droplets as substrates for the activation of B cells. These droplets have the advantage to have a liquid surface, allowing the antibodies-coated diffusion at their surface. Moreover, these droplets are potentially deformable, so they behave as cellular force probes. Lastly, the droplets have the same size of the B cells, so they mimic the antigen-presenting cells. In order to put in contact the B cells with the droplets, we fabricated a regular network of microfluic traps with U-shape in a microfluic chamber. The shape of the chamber has been optimized to guaranty a good trapping efficiency. Using the traps, we have been able to put into contact one antibody-coated droplet with one B cell in several traps in parallel, and to observe the contact in function of time by fluorescence microscopy. We observed an accumulation of the antibodies coated on the droplet at the surface of contact. The kinetics of accumulation has been measured and the time scale of accumulation has been deduced. Also, observations with fluorescence showed a polarization of the lysosomes near the contact, suggesting a B cell response.

Introdução: as doenças linfoproliferativas de células B maduras correspondem a cerca de 80% das neoplasias linfoides, são caracterizadas pela proliferação clonal de uma célula B precursora em diferentes estágios de diferenciação. A semelhança imunofenotípica a um dado estágio maturativo é relevante para o diagnóstico diferencial através da imunofenotipagem por citometria de fluxo, embora a sobreposição de expressões possa dificultar a identificação correta de cada linfoproliferação. Alguns marcadores são pouco conhecidos nas diferentes linfoproliferações B e há pouca literatura analisando os dados quantitativamente, sendo grande parte qualitativa. Objetivos: este trabalho avalia a expressão quantitativa em intensidade de fluorescência média (IFM) dos anticorpos CD200, CD43, CD52 e CD123 no diagnóstico diferencial das doenças linfoproliferativas B crônicas. Métodos: estudo transversal, com 124 amostras de pacientes em investigação diagnóstica de doenças linfoproliferativas que realizaram imunofenotipagem em um centro de referência em neoplasias hematológicas no período de outubro de 2014 a junho de 2015. Foram analisadas as IFMs de cada marcador nas onze diferentes doenças diagnosticadas. Resultados: as neoplasias dos 124 pacientes analisados foram: 81 leucemias linfocíticas crônicas (LLC), 17 linfomas de zona marginal (LZM), 9 linfomas linfoplasmocíticos (LLPL), 6 linfomas do manto (LM), 2 tricoleucemias (TRL), 2 tricoleucemias variantes (TRLv), 5 linfomas foliculares (LF), 1 linfoma de Burkitt e 1 linfoma difuso de grandes células B (LDGCB). A expressão mediana do CD200 foi de 46,8 (intervalo: 1,5-334). A expressão mediana de CD200 foi maior na TRL (incluindo a TRLv) e na LLC (85 e 61,2, respectivamente). A expressão de IFM do CD200 na TRLv diferiu quando comparado à TRL na sua forma clássica (mediana: 36,1 versus 220,3). A mesma diferença foi observada na expressão do CD123 quando comparada a TRL à TRLv. Verificamos, que casos de LZM demonstraram IFM medianas de CD43 de 7,1 (intervalo: 1,1-106), em comparação a casos de LM e LLC, nos quais as medianas de IFM do CD43 foram 90 e 176, respectivamente. A comparação da intensidade de CD52 entre amostras demostrou diferença estatisticamente significativa entre LLC e LZM com medianas de IFM de 775,5 versus 1297,0 (P=0,04). Conclusões: nossos resultados sugerem que a citometria de fluxo quantitativa desses marcadores pode ser uma ferramenta adicional útil na identificação de alguns tipos de DLPCBs. / Background: lymphoproliferative disorders of mature B cells account for about 80% of the lymphoid malignancies. They are characterized by the clonal proliferation of a B cell precursor at different stages of differentiation. The similarity of a given phenotypical maturation stage is relevant for the differential diagnosis by immunophenotyping, however overlap in cell morphology and immunologic features may difficult the correct identification of each pathology. Some markers are not well known in different B lymphoproliferative neoplasms and there is little literature analyzing the data quantitatively. Objectives: this study evaluated the expression of CD200, CD43, CD52 and CD123 by flow cytometry on B-cell chronic lymphoproliferative disorders (BCLDs) differential diagnosis. Methods: cross-sectional study, of 124 samples from patients for diagnostic investigation of lymphoproliferative disorders who underwent immunophenotyping in a referral center for hematologic malignancies from October 2014 to June 2015. MFIs were analyzed for each marker in eleven different diagnosed pathologies. Results: the diseases of the 124 patients investigated comprised: 81 chronic lymphocytic leukemia (CLL), 17 marginal zone lymphoma (MZL), 9 lymphoplasmacytic lymphoma (LPL), 6 mantle cell lymphoma (MCL), 2 hairy cell leukemia (HCL), 2 hairy cell leukemia variant (HCLv), 5 folicular lymphoma (FL), 1 Burkitt lymphoma (BL) e 1 diffuse large B cell lymphoma (DLBCL). The CD200 median MFI expression was 46,8 (range: 1,5-334). CD200 was higher in HCL (including HCLv) and CLL cells (85 and 61,2 respectively). HCLv difference in CD200 MFI, when compared to classical HCL (median 36,1 versus 220,3). The same difference in CD123 expression was observed when comparing HCL versus HCLv. We found that cases of MZL exhibited CD43 median MFI of 7,1 (range: 1,1-106), in contrast to cases of MCL and CLL, which had median MFIs for CD43 of 90 and 176, respectively. The comparison of CD52 intensity between CLL and MZL samples showed statistically significant difference with a median MFI of 777,5 versus 1297,0 (P=0,04). Conclusion: our results suggest that quantitative flow cytometry of these markers may be a useful additional tool to better identify some types of BCLDs.