Thesis (Ph. D.) -- University of Texas Southwestern Medical Center at Dallas, 2005. / Vita. Bibliography: 153-180.

Thesis (Ph.D.)--University of Alberta, 2009. / A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Immunology, Department of Medical Microbiology and Immunology. Title from pdf file main screen (viewed on September 3, 2009). Includes bibliographical references.

Thesis (Ph.D.)--University of Alberta, 2010. / A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy, Department of Medical Microbiology and Immunology. Title from pdf file main screen (viewed on April 24, 2010). Includes bibliographical references.

Thesis (Ph. D.)--Ohio State University, 2006. / Available online via OhioLINK's ETD Center; full text release delayed at author's request until 2009 Apr 26

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 108-129).

Thesis (Ph.D. in Immunology) -- University of Colorado, 2005. / Typescript. Includes bibliographical references (leaves 133-151). Free to UCDHSC affiliates. Online version available via ProQuest Digital Dissertations;

The overall emphasis in this thesis is the study of the regulation of virus infections by natural killer (NK) cells. In initial analyses, vaccinia virus (VV)-infected cells were found to be more sensitive to NK cell-mediated lysis during a discrete period of time post-infection. This enhanced susceptibility to lysis correlated with enhanced triggering (but not binding) of the effector cells and a concomitant decrease in target cell H-2 class I antigen expression. Furthermore, VV-infected cells became resistant to lysis by allospecific cytotoxic T lymphocytes (CTL) at a time when they were very sensitive to killing by NK cells or VV-specific CTL. This suggested that alterations in class I MHC antigens may affect target cell sensitivity to lysis by NK cells. The hypothesis that viral peptide charging of H-2 class I molecules can modulate target cell sensitivity to NK cell-mediated lysis was tested by treating target cells with synthetic viral peptides corresponding to the natural or minimal immunodominant epitopes defined for virus-specific CTL, and then target cell susceptibility to NK cell-mediated lysis was assessed. None of the 12 synthetic viral peptides used were able to significantly alter target cell lysis by NK cells under any of the conditions tested. In order to determine if H-2 class I molecules were required in the regulation of a virus infection by NK cells in vivo, intact or NK depleted (treated with anti-asialo GM1 antiserum) β2-microglobulin-deficient [β2m (-/-)] mice, which possess a defect in H-2 class I antigen expression, were infected with the prototypic NK-sensitive virus, murine cytomegalovirus (MCMV). In anti-asialo GM1-treated β2m (-/-) mice, as well as in β2m + (H-2 class I normal) control mice also treated with anti-asialo GM1 a significant enhancement in splenic MCMV titers as compared to NK-intact animals, was observed. When thymocyte expression of H-2 class I molecules (H-2Db) in normal mice was analyzed, it was found that following MCMV infection, H-2Db expression was significantly greater than the low level of expression found in uninfected thymocytes. In marked contrast, thymocytes from β2m (-/-) mice did not display any detectable H-2Db before or after infection. These in vivoresults demonstrate that NK cells can regulate a virus infection, at least in the case of MCMV, independent of H-2 class I molecule expression. Thymocytes from uninfected normal mice were found to be very sensitive to NK cell-mediated lysis, whereas those from MCMV-infected animals were completely resistant, presumably due to the protective effects of MCMV-induced interferon (IFN). However, thymocytes from MCMV-infected β2m (-/-) mice were only slightly protected from lysis by NK cells, consistent with the inverse correlation between MHC class I antigen expression and sensitivity to NK cell-mediated lysis. These results provide in vivoevidence suggesting a requirement for MHC class I molecules in IFN-mediated protection from lysis by NK cells. In addition to the analysis of H-2 class I molecules on target cells, the identity of a molecule present on the surface of all NK cells and other cytotoxic effector cells, which is recognized by a monoclonal antibody (mAb) generated in this laboratory designated CZ-1, and can also modulate NK cell triggering, was also of interest. This laboratory has previously reported that this antigen is upregulated on cytotoxic (and other) lymphocytes following a virus infection in vivo, or upon activation in vitro. Using competitive FACS analysis and fibroblasts transfected with various isoforms of CD45, it was found that mAb CZ-1 recognizes a sialic acid-dependent epitope associated with a subpopulation of CD45RB molecules.

Base teórica: A sepse é uma síndrome heterogênea, definida como disfunção orgânica que ameaça à vida, causada por uma resposta desregulada do hospedeiro à infecção. É um problema de saúde mundial, graças à sua alta prevalência, morbimortalidade associada, além de custos para seu tratamento. As células Natural Killer (NK) fazem parte do sistema imune inato reconhecendo moléculas de HLA de classe I em células alvo, através de seus receptores de membrana killer cell immunoglobulin-like receptors (KIR). A intensidade da resposta à infecção pode variar entre indivíduos, logo pode-se considerar que esta seja determinada por bases genéticas, e estas influenciem na ocorrência de sepse e variabilidade nos desfechos. Objetivos: Avaliar a associação entre os genes KIR e os ligantes HLA em pacientes críticos, comparando pacientes com sepse e controles não sépticos internados na mesma UTI. Métodos: Foi examinado o polimorfismo de 16 genes KIR e seus ligantes HLA em 271 pacientes críticos, caucasóides, sendo 211 pacientes com sepse e 60 controles, pela técnica de PCR-SSO e PCR-SSP, respectivamente. Resultados: Os genes ativadores KIR2DS1 e KIR3DS1 foram mais frequentes nos controles que nos pacientes com sepse (41,23% versus 55,00%, e 36,49% versus 51,67%; p = 0.041 e 0,025, respectivamente). Estes resultados fornecem informação inicial sobre o papel de polimorfismos de KIR na sepse, sugerindo que este possa ser um potencial marcador diagnóstico ou prognóstico da doença. / Background: Sepsis is a heterogeneous syndrome, defined a life-threatening organic dysfunction caused by a dysregulated host response to infection. Sepsis is a global health problem, due to its high prevalence, associated morbidity and mortality, and costs for its treatment. Cells Natural Killer (NK) cells are part of the innate immune system that recognize HLA class I molecules on target cells via membrane receptors called killer cell immunoglobulin-like receptors (KIR). The intensity of the response to an infection may vary among individuals and might be influenced genetic features affecting sepsis occurrence and variability in outcomes. Objectives: To evaluate the association between KIR genes and HLA ligands in critically ill patients, comparing patients with sepsis and without sepsis admitted to the same ICU. Methods: We examined the polymorphism of 16 KIR genes and their HLA ligands in 271 critically ill patients, Caucasians, and 211 patients with sepsis and 60 controls by PCR-SSO and PCR-SSP, respectively. Results: Activating KIR2DS1 and KIR3DS1 genes were more common in controls than in patients with sepsis (41.23% versus 55.00% and 36.49% versus 51.67%, p = 0.041 and 0.025, respectively). These results provide initial information on the role of polymorphism of KIR in sepsis, suggesting that this may be a potential diagnostic or prognostic marker of the disease.

Ly49 receptors are the canonical natural killer cell class-I major histocompatibility complex receptors expressed in mice. They have a well-defined role in natural killer cell self/non-self discrimination and in the developmental licensing of functional natural killer cells. In this thesis, I report two novel aspects of Ly49 receptor biology. First, I show that their expression may be regulated by specific nucleosome occupancy on AML-1 binding sites within the distal Ly49 promoter. This finding sheds light on a potential regulatory pathway that has thus far been unexplored in studies of the Ly49 receptor family, and highlights the Ly49 family as an ideal model system in which to study the impact of nucleosome occupancy in general. Second, I show that Ly49 receptors have a central and indispensable role in the emerging phenomenon known as adaptive natural killer cell memory. Natural killer cells have recently been observed displaying adaptive, long-lived, antigen specific memory responses comparable to T cell memory responses, but no explanatory mechanism has been discovered to describe how adaptive memory is possible in these ‘innate’ immune cells. Using Ly49-deficient mice, I show that the inhibitory, self-specific Ly49 receptors Ly49C and Ly49I are required for adaptive memory responses to chemical haptens or protein antigens. Moreover, I show that Ly49C/I binding capabilities are required during all stages of the memory response, as is antigen presentation in the context of class I major histocompatibility complex, again analogous to T cell memory responses. I present initial findings implicating these Ly49 receptors as key components of the antigen recognition process itself, and propose a mechanism based in evolutionarily ancient immunology to explain how this specificity could arise. Finally, I demonstrate that Ly49-dependent natural killer cell memory is capable of mediating powerful anti-cancer vaccination effects using an aggressive model of melanoma. Together, these findings in Ly49 family expression regulation and its functional role in adaptive NK cell responses open several new avenues of study in Ly49 receptor biology and natural killer cell immunology.

Base teórica: A sepse é uma síndrome heterogênea, definida como disfunção orgânica que ameaça à vida, causada por uma resposta desregulada do hospedeiro à infecção. É um problema de saúde mundial, graças à sua alta prevalência, morbimortalidade associada, além de custos para seu tratamento. As células Natural Killer (NK) fazem parte do sistema imune inato reconhecendo moléculas de HLA de classe I em células alvo, através de seus receptores de membrana killer cell immunoglobulin-like receptors (KIR). A intensidade da resposta à infecção pode variar entre indivíduos, logo pode-se considerar que esta seja determinada por bases genéticas, e estas influenciem na ocorrência de sepse e variabilidade nos desfechos. Objetivos: Avaliar a associação entre os genes KIR e os ligantes HLA em pacientes críticos, comparando pacientes com sepse e controles não sépticos internados na mesma UTI. Métodos: Foi examinado o polimorfismo de 16 genes KIR e seus ligantes HLA em 271 pacientes críticos, caucasóides, sendo 211 pacientes com sepse e 60 controles, pela técnica de PCR-SSO e PCR-SSP, respectivamente. Resultados: Os genes ativadores KIR2DS1 e KIR3DS1 foram mais frequentes nos controles que nos pacientes com sepse (41,23% versus 55,00%, e 36,49% versus 51,67%; p = 0.041 e 0,025, respectivamente). Estes resultados fornecem informação inicial sobre o papel de polimorfismos de KIR na sepse, sugerindo que este possa ser um potencial marcador diagnóstico ou prognóstico da doença. / Background: Sepsis is a heterogeneous syndrome, defined a life-threatening organic dysfunction caused by a dysregulated host response to infection. Sepsis is a global health problem, due to its high prevalence, associated morbidity and mortality, and costs for its treatment. Cells Natural Killer (NK) cells are part of the innate immune system that recognize HLA class I molecules on target cells via membrane receptors called killer cell immunoglobulin-like receptors (KIR). The intensity of the response to an infection may vary among individuals and might be influenced genetic features affecting sepsis occurrence and variability in outcomes. Objectives: To evaluate the association between KIR genes and HLA ligands in critically ill patients, comparing patients with sepsis and without sepsis admitted to the same ICU. Methods: We examined the polymorphism of 16 KIR genes and their HLA ligands in 271 critically ill patients, Caucasians, and 211 patients with sepsis and 60 controls by PCR-SSO and PCR-SSP, respectively. Results: Activating KIR2DS1 and KIR3DS1 genes were more common in controls than in patients with sepsis (41.23% versus 55.00% and 36.49% versus 51.67%, p = 0.041 and 0.025, respectively). These results provide initial information on the role of polymorphism of KIR in sepsis, suggesting that this may be a potential diagnostic or prognostic marker of the disease.