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Study of receptor-ligand pair NKR-P1F and Clrg
Kotýnková, Kristýna ; Man, Petr (advisor) ; Schneider, Bohdan (referee)
Study of receptor-ligand pair NKR-P1F and Clrg Mouse NKR-P1F:Clr-g receptor:ligand pair is important component of the receptor "zipper" that occurs at the contact between natural killer cell and its target cell, and represents a recently discovered example of lectin-lectin interactions important for recognition among immune cell subsets. In order to study structure of these proteins and interactions between them, we have prepared pET-30a(+) bacterial expression vectors coding parts of extracellular domains of the two receptors. After induction of protein production with IPTG, the proteins precipitated into inclusion bodies, from which they could be refolded in vitro. Refolded proteins were purified using combination of ion exchange and size exclusion chromatography. NKR-P1F construct yielded only small amounts of soluble protein using standard refolding protocols. Furthermore we have experienced difficulties with reproducibility of the refolding results. In the case of Clrg the standard protocols for protein refolding were not sufficient. In order for the Clrg to fold properly, the odd cysteine which does not fit into the pattern usual for this family of receptors was substituted for serine and resulting C148S construct was shown to be more useful. Further, using (benzyldimethylammonio)propanesulfonate in...
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Studies on interactions between NKR-P1D and Clrb membrane receptors
Hanč, Pavel ; Novák, Petr (advisor) ; Brdička, Tomáš (referee)
Studies on interactions between NKR-P1D and Clrb membrane receptors Interaction between murine NKR-P1D and Clrb receptors was originally described as a novel type of "MHC class-I independent missing-self recognition" and was shown to confer protection from killing by natural killer cells.[1] However, further study brought conflicting results suggesting that NKR-P1D does not binds Clrb strongly if it does at all.[2] In order to address the issues arising from these conflicting results, we have recombinantly expressed the extracellular domains of both receptors in E. coli cells and refolded the proteins in vitro. The quality of refolding was confirmed both by determining the disulphide bonding pattern using FTMS and measuring 1 H/15 N-HSQC spectra. By means of size exclusion chromatography and analytical ultracentrifuge we were unable to provide convincing results for the interaction itself. However, using SPR technique, a weak, specific, pH-dependent interaction was observed. Interaction between the proteins in solution was immobilized using chemical cross-linking technique. Three cross-linking reagents, EDC, DSG and DSS were used. The reaction mixture was separated by means of SDS-PAGE and protein bands corresponding to dimers were digested in gel. Using FT-MS we were able to find peptides from both...
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Recombinant preparation of isotopically labeled receptor rNKR-P1A for NMR studies
Čonka, Martin ; Novák, Petr (referee) ; Bezouška, Karel (advisor)
anglicky NK cells belong to the population of cells which are able to cytotoxic kill certain tumor and cells infected by viruses. This bachelor thesis focuses on the rat's NK cell receptor, especially rNKR-P1A. This protein belongs to the activating receptors and is able to activate the cytotoxic function of NK cells. Physiological ligand and three-dimensional structure of this protein has not been resolved yet. The aim of this work was optimalization of production rNKR-P1A in minimal medium and thereafter producing isotope-labeled proteins. Isotope- labeled proteins could contribute to solving the three-dimensional structure of this rat receptor by using NMR methods.
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In vitro expansion and activation of natural killer cells for cell therapy.
BENEŠOVÁ, Monika
NK cells are part of the non-specific immune response and are one of the main components of antitumor immunity. They do not need antigen stimul for thein activation but recognize damaged ( transformed ) cells by characteristic decreased expression of MHC I molecules. These natural killers become subjekt of many clinical studies based on the use of anti-tumor activity of NK cells for both solid tumors and in hemato - oncological diseases. The aim of this study was to find optimal conditions for in vitro expansion and activation of NK cells. NK cells were isolated from mononuclear cell fraction by magnetic separation and cultured in two types of media SCGM and X - VIVO 10 with the addition of interleukin-2 respectively OKT3 antibody. The influence of the mononuclear cells on proliferation of NK cells was tested. After a 6- day culture , the cells were passaged and growth of NK cells was determined using hematological analyzer and flow cytometry. Expression of the activation markers CD25 and CD336 (NKp44) was observed. All experiments were conducted under conditions of good manufacturing practice. Slightly higher gain of NK cells was observed in SCGM media without a significant differences in the other additives. Much higher number of NK cells was observed in culture with supporting irradiated mononuclear cells. There were no differences in cultures with autologous or allogeneic cells. We found that NK cells with higher proliferative potential express increasingly CD25, unlike the cells with decreased proliferation which had increased expression of CD336 marker. The work led to the definition of the optimal culture conditions for NK cells and became the basis for the further development of the medicinal product from in vitro activated NK cells.
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