The nurse shark, Ginglymostoma cirratum, is a sedentary shark species that inhabits coral reefs in the tropical and subtropical Atlantic Ocean and along the western coast of the Americas in the Pacific Ocean. Nurse shark tissue samples were collected from the Bahamas, Belize, Brazil, and Dry Tortugas National Park in Florida. 186 individuals were genotyped at 11 microsatellite loci, the control region of the mitochondrial genome was sequenced in 190 individuals, and 89 individuals from the Bahamas, Belize, and Dry Tortugas were genotyped at the major histocompatibility complex (MHC) class IIα locus. An analysis of molecular variance (AMOVA) for the microsatellite loci indicated significant subdivision only between the Bahamas and Dry Tortugas populations. An AMOVA for the mitochondrial control region sequences indicated significant subdivision between all population pairs. The AMOVA for MHC class IIα locus indicated significant subdivision between two population pairs: the Bahamas population and the Dry Tortugas population and the Belize population and the Dry Tortugas population. The nurse shark has the lowest mitochondrial DNA nucleotide diversity (π=0.0125%) and haplotype diversity (h=0.2402) of any shark species to date. There were 14 MHC alleles from 39 polymorphic sites; ten were the same as published alleles (Kasahara et al. 1993; Ohta et al. 2000). This study was the first study to use MHC class IIα genes as a marker for population genetics in sharks. Our results showed that MHC class IIα locus behaves as a diploid locus and is a powerful tool for determining population genetic structure between populations.

Natural killer (NK) cells are lymphocytes of the innate immune system that play a major role in the destruction of both tumours and virally-infected cells. The cytotoxicity of NK cells is tightly controlled by signals received through activating and inhibitory receptors. NK cells express a variety of inhibitory receptors such as Ly49 receptors. Ly49 receptors bind to class I MHC molecules that expressed on normal cells. Using Ly49-deficient (NKCKD) mice we show that Ly49-KD NK cells successfully recognize and kill influenza virus-infected cells and that NKCKD mice exhibit better survival than wild-type mice. Moreover, influenza virus infection has a propensity to upregulate cell surface expression of MHC-I on murine lung epithelial cells in vivo. Significantly, we demonstrate increased lung damage of WT-mice versus NKCKD mice after influenza virus infection as determined by histological analyses. This data indicated that absence of Ly49 inhibitory NK receptors greatly enhances survival of infected mice.

The major histocompatibility complex class I (MHC-I) antigen presentation pathway is necessary for the immune system to be able to detect, control, and eliminate cancers. MHC-I binds oligopeptides derived from cellular proteins and presents them on the cell surface to CD8+ T cells. Consequently, the CD8+ T cells can monitor whether any cells are making abnormal proteins and, if so, can destroy those cells. Because MHC-I presentation is not essential for cell viability, immune selection pressure often leads to cancers that are MHC-I low as they can better evade CD8+ T cell recognition. It is, therefore, important to fully understand the mechanisms of MHC-I presentation as this will identify new ways to target and exploit the pathway for cancer therapeutics. Although several components of the MHC-I pathway have already been characterized, some knowledge gaps remain. Unbiased forward genetic screens from our lab identified some novel gene candidates, such as IRF2, which positively regulate MHC-I presentation. In this dissertation, I will reveal which antigen presentation pathway genes are transcriptionally controlled by IRF2 and contribute to the MHC-I presentation deficiency observed in cells lacking IRF2 and I will also show that IRF2 negatively regulates PD-L1 expression. By influencing both MHC-I antigen presentation and PD-L1 expression in this manner, cancers lacking IRF2 (of which there are many) are both harder to see and more difficult to eliminate.

MHC glycoproteins are an essential part of adaptive immunity and may also play a role in mate choice. In addition, MHC genes are the most variable of all known genes. For these reasons, they have been intensively studied for several last decades. However, research is complicated due to extreme variability and frequent duplications. The Eurasian beaver seems to serve as an interesting model. It underwent a dramatic bottleneck culminating in the end of 19th century, when only about 1,200 individuals survived in several isolated relic populations. Thanks to numerous reintroductions, beavers of various origin meet in newly established populations. However, knowledge of beaver MHC was very limited. Only a single MHC gene has been investigated in a detail, and some relic populations were not sampled. Utilising additional relic populations and additional MHC locus, I verified a significant reduction of the variability of beaver MHC genes and also found signs of selection in the past. Then I sequenced MHC loci in two newly formed populations. I confirmed the ongoing selection by the disruption of cytonuclear equilibrium and the advantage of divergent alleles. We therefore can have a unique insight into the several periods of the history of beaver populations: In the past, MHC diversity was shaped by a...

The aim of our study was to simulate in rats all aspects and techniques used in our new clinical program of cryopreserved alloarterial transplantation and investigate the influence of two immunosuppressive protocols with tacrolimus on acute rejection of these allografts. Cryopreserved abdominal aortic grafts were transplanted between Brown-Norway and Lewis rats. Tacrolimus (0,2 mg/kg daily) was administered from day 1 to day 30 (TAC1) or from day 7 to day 30 (TAC7), respectively. No immunosuppressed isogeneic (ISO) and allogeneic (ALO) rats combination served as control. Aortal wall destruction and infiltration by immunocompetent cells (MHC II+ cells of recipient origin) was studied on day 30 after transplantation. Flow cytometry was used for the analysis of day 30 sera for the presence of donor specific anti-MHC class I and II antibodies. The aortal allografts in both immunosuppressed groups showed regular morphology of aortal wall with no depositions of immunoglobulin G on day 30. The adventitial infiltration of non-immunosuppressed aortal allografts by MHC class II positive cells of recipient origin was significantly higher (ALO 20,7±6,7 cells, P <0,001) compared to both immunosuppressed groups (TAC1 5,9±5,5 cells, TAC7 6,1±5,1 cells). Anti-MHC antibodies class I and II level in peripheral blood...

The diploma thesis is focused on the verification of inheritance of selected microsatellites from the microsatellite panel of the MHC locus in camels. The theoretical part deals with the characteristics of the genus Camelus. Special focus is given to adaptation mechanisms allowing camels to survive in conditions that are inhospitable for other livestock species. Microsatellites which are also described became an excellent choice not only in parentage analysis. The practical part was based on fragment analysis in genetic analyser ABI PRISM 3500, which preceded DNA isolation, multiplex PCR amplification and gel electrophoresis. Using GeneMapper 5 software, amplified fragment sizes were calculated and mendelian segregation verified. For assembly microsatellite panel four microsatellite markers were selected, M29_I, M35_II, M41_III a M42_III. The least polymorphic was microsatellite M29_I of the MHC I region and the most polymorphic was microsatellite M42_III of the MHC III region. In general, microsatellites from the microsatellite panel can be considered reliable for verifying the origin of the alleles and can be further used to reveal polymorphism of the MHC region of camels.

京都大学 / 新制・課程博士 / 博士(医学) / 甲第23604号 / 医博第4791号 / 新制||医||1055(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 戸口田 淳也, 教授 河本 宏, 教授 江藤 浩之 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 新制・課程博士 / 博士(医学) / 甲第24792号 / 医博第4984号 / 新制||医||1066(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 椛島 健治, 教授 辻川 明孝, 教授 山中 伸弥 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

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