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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Immunological studies on Brucellosis with special reference to the use of S.I9 vaccine in cattle

McDiarmid, A. January 1954 (has links)
No description available.
2

Flow injection immunoassays using solid phase immunoreactors and fluorescence detection

Khokhar, Muhammad Y. January 1993 (has links)
The use of flow injection analysis with fluorescence detection was evaluated using the host-guest phenomenon between the cyclodexnins and DL-Iysine and Lserine. Auorescence enhancement, kinetic and equilibrium studies were recorded and the effect of pH and time on fluorescence were also observed. Rhodamine isothiocyanate was conjugated to insulin. Insulin and dye were mixed in different ratios, and the dye : insulin ratio was detennined for each conjugate. These conjugates were checked for immunoreactivity. Insulin-biotin and antibody-iminobiotin conjugates were also prepared. Insulin : biotin ratio was also determined. An insulin-biotin avidin-Texas Red complex was also prepared. Each was checked for immunoreactivity. Protein G-agarose, protein A-controlled pore glass(CPG), streptavidin-agarose, and avidin D-agarose-biotin-antibody solid phase immunoreactors were used in flow injection immunoassay of insulin. In these immunoassays, antibody, insulin and labelled insulin were incubated in vitro and then injected onto the immunoreactor. A binding buffer carried the sample through the immunoreactor and a fluorescent detector. An acidic buffer then eluted the components of the sample bound to the immunoreactor, which were then measured. An assay range for insulin was developed in each solid phase assay.
3

How B cells influence T cell responses

Crawford, A. January 2005 (has links)
Although studies using B cell deficient mice have been useful in understanding the importance of B cells under different conditions, it is difficult to then dissect exactly how B cells could be regulating T cell responses. By transferring OT-II transgenic T cells into either B cell deficient (μMT) or C57BL/6 mice, expansion and contraction of T cells can be tracked <i>ex vivo. </i>Expansion of OT-II cells is reduced in μMT mice compared to C57BL/6 mice. Thus, B cells can provide costimulatory signals, secrete cytokines and influence the lymphoid microarchitecture. To dissect which B cell factor(s) are involved in enhancing OT-II T cell expansion, a model system was used where one molecule on the B cells is depleted at one time. This was achieved by creating bone-marrow chimeras using a combination of μMT bone-marrow and wildtype or deficient bone-marrow. Thus, all the B cells are either wildtype or deficient for a particular molecule. The molecules examined were MHC-II, which is required for antigen presentation, CD40, due to its costimulatory role, and lymphotoxin-alpha, for its role in maintenance of splenic architecture. Using the OT-II adoptive transfer system, we have shown a requirement for MHC-II but not CD40 on B cells for efficient T cell expansion. In light of these observations, the role of B cell-derived MHC-II for T cell memory generation was examined. To do this, I used MHC-II tetramers to track a polyclonal population of T cells in the host.  Using this technique, I have shown that T cell memory is also diminished when the B cells do not express MHC-II. Thus, a cognate interaction with B cells is required for both efficient expansion and memory generation of CD4<sup>+</sup> T cells.
4

Non-specific recognition by macrophages and mechanisms of macrophage activation

Ogmundsdottir, H. M. January 1979 (has links)
This study deals with two related aspects of macrophage function, surface recognition and signal transmission across the plasma membrane. The introduction reviews the properties and functions of macrophages with particular reference to specific and non-specific recognition and activation as expressed by enhanced effector function. This review is set against the background of the structure and function of plasma membranes, biological recognition and mechanisms of cellular activation. The ability of macrophages to recognize a variety of foreign particles without the mediation of specific recognition molecules was investigated. In a binding assay performed at 4°C using non-opsonized bacteria, it was found that several types of Gram-positive and Gram-negative bacteria bound to normal mouse peritoneal macrophages. The binding could be inhibited by pre-incubating the macrophages at 4°C with various monosaccharides at a concentration of 10 aM. There was a very close correlation between the ability of a sugar to inhibit binding of a particular type of bacterium and the presence of that sugar in the bacterial cell wall. It was, therefore, postulated that the binding of non-opsonized bacteria by macrophages was based on the recognition of cell wall carbohydrates. The nature of the binding reaction was further studied using Corvnebacterium parvum. It was found that binding at 4°C depended on the presence of both Ca++- and MgtLions whilst binding at 20°C occurred to some degree when only Mg++-ions were present. The binding was not mediated by cell-bound antibody as shown by experiments using mild trypsin-treatment and specific antibody. Pro-treatment of the macrophages with trypain, process, /3-galactosidase and phospholipases A, C and D caused a marked reduction in binding whilst treatment with neuraminidase resulted in some increase in binding. Exposure of the macrophages to periodate also led to a decrease in binding of C. parvum, an effect largely reversed by subsequent treatment with borohydride. Recovery from the effects of enzyme treatment was rapid, but was inhibited by EDT& in the case of trypsin and β3-galactosidase. These results suggested that plasma membrane glycoproteins played an important part in the binding reaction which might involve a bridging action of divalent cations. The effect of neuraminidase was most easily explained by a reduction in cell surface negative charge. The enhancement of phosphatidyl inositol turnover was investigated as a possible mechanism of signal transmission initiating the intracellular effects of an activating agent following contact with the macrophage surface. The rate of phosphatidyl inositol turnover was assayed by measuring the uptake of tritiated Wo-iuositol into macrophage phosphatidyl inositol during one hour, It was shown that two macrophage activating agents, endotoxin and C. parvum caused an increase in phosphatidyl inositol turnover after 4 hours of incubation whilst exposure to three inert particles, Staphylococcus albus, latex and collol 1 carbon, had no such effect. All the particles tested were phagooytoses, and it was concluded that enhanced turnover of phosphatidyl inolitol was an ear1y event following exposure to activating agents that was not linked to the process of phagocytosis.
5

Structural and functional characterisation of avian IgY

Taylor, Alexander Iain January 2007 (has links)
No description available.
6

Role of SOCS2 in CD4+ T cell development and function

Knosp, C. A. January 2012 (has links)
No description available.
7

Development of antibodies for life-detection experiment in extreme environments : implications for astrobiology

Derveni, Maria Elisavet January 2010 (has links)
The Life Marker Chip (LMC) instrument is an antibody assay-based system which will attempt to detect molecular signatures of Life in the Martian subsurface as part of the payload on board the European Space Agency (ESA) ExoMars mission rover, currently scheduled for launch in 2018. The LMC will have the ability to detect up to 25 different molecular targets of different origins that are associated with meteoritic in-fall, extinct or extant Life, prebiotic chemistry and spacecraft contamination. Regolith / crushed rock samples will be collected for the LMC by the rover and subjected to solvent extraction to extract organic molecules for analysis by the immunoassays. One of the key stages in the development of the LMC is the selection of antibodies to be used in the flight instrument. The challenge lies in the nature of the molecules or classes of molecules that are LMC targets and the need for antibodies that remain functional in the extreme conditions during a planetary exploration mission, especially the radiation environments. The work described within focuses on two main aspects of the search for LMC-relevant antibodies; the effect of space radiation on antibody performance [in the form of both ground-based and Low Earth Orbit (LEO)-set studies] and the development of ―customised‖antibodies against some of the molecules that are being investigated as potential LMC targets. The need to study the effects of space radiation on antibodies arose due to lack of any heritage of their use in interplanetary missions. For all the antibodies in the LMC, the ability to resist inactivation due to space radiation seen during a Mars mission will be a prerequisite. The objective of the ground-based radiation studies was to expose a number of LMC-relevant antibodies to simulated Mars mission radiation in the form of proton and neutron radiation which are the components of the mission radiation environment that are expected to have the dominant effect on the operation of the LMC. Cont/d.
8

The transfer of antibody from mother to foetus in the guinea-pig

Al-Najdi, Maha Raouf January 1965 (has links)
In their early development and before their antibodyforming mechanism is fully established the young of mammals depend entirely on the maternal supply of antibodies. The passive transfer of immunity acquired by the young from its mother can occur before birth, after birth, or both. In man, rabbit and guinea-pig, for example, the transfer of immunity from mother to young occurs entirely prenatally. In the ungulate, horse and pig the passive transfer of immunity occurs postnatally, whilst in dog, rat and mouse it occurs both pre- and postnatally. The difference between these groups in the mechanism of antibody transfer from mother to young was earlier thought to be due to the difference in the number of layers intervening between the maternal and the foetal circulations (Kuttner and Ratner, 1923). In other words the structure of the placenta was the decisive' factor in the mechanism of the transfer of passive impunity to the young. According to Grosser's (1909; 1927) classification, there are four types of mammalian placental structure. (1) the epitheliochorial with six intervening layers, (2) the syndesmochorial with five, (3) the endotheliochorial with four and (4) the haemochorial placenta with three. These were later modified by Mossnan (1926), who added a fifth type, the haemoendothelial with one. Since animals with epitheliochorial and syndesmochorial placentae transfer antibody entirely postnatally to their young, whereas in those with haemochorial and haemoendothelial placentae transfer is mainly prenatal (with the exception of rats and mice where transfer is mainly postnatal), and in those with endotheliochorial placentae both prenatal and postnatal transfer is considerable, it was perhaps not surprising that a'purely physical hypothesis of antibody transfer should be generally accepted. But in 1946 Hartley showed that the human placenta was selective in transferring antibody, so, that refined horse antibody was not transferred to the foetus at all, while human. antibody passed freely. Shortly after, in a series of papers, Brambell and his colleagues (1949, 1950,1951,1952) showed that there was considerable doubt whether in rabbits antibody is transferred via the placenta at all. They suggested that antibody circulating in pregnant rabbits is secreted into the uterine cavity, whence it passes via the yolk-sac splanchnopleur into the foetal circulation. Moreover they showed that the yolk-sac splanchnopleur is a highly selective membrane, differentiating between -globulins not by molecular size but by*species of origin. In particular Brambell, Hemmings and Oakley (1959) showed that rabbit antibody digested with pepsin was less readily transferred to the foetus, notwithstanding its lower molecular weight, than the unmodified antibody. When rabbit -globulin wap digested with papain (Brambell, Hemmings, Oakley and Porter, 1960) to yield Porter's fractions 1, II and III and these fractions were injected into the rabbit uterine cavity, fraction III was transferred to the foetus almost as well as the unmodified -globulin, fraction I and II much less well. In the Guinea-pig the route of antibody transfer from mother to young was also shown to be via the yolksac splanchnopleur and the vitelline circulation of the foetus (Barnes, 1957). The present work was undertaken to investigate by the technique of intra-uterine injections of antitoxic sera used by Brambell and colleagues the selectivity of the yolk-sac splanchnopleur of the guinea-pig foetus for homologous and various heterologous antitoxins and for the antibody fragments obtained by the peptic digestion of the antitoxin molecule.
9

Functional and genetic identification of lineage committed intrathymic progenitors in adult mice

Belyaev, Nikolai Nikolaevich January 2007 (has links)
T-lymphocytes are an essential component of the adaptive immune system and require a distinct anatomical location for their development, namely the thymus. This study focuses on early events during development of these cells in the adult mouse. The most immature compartment of murine thymocytes is subdivided by the cell surface expression of CD44 and CD25. The most primitive progenitor population resides in the CD44+CD25-double negative 1 (DN1) fraction and can be further subdivided according to expression of the receptor tyrosine kinase c-kit (CD 117). The DN1 CD117+ fraction is homogeneous, unlike the CD117-fraction, which constitutes a preponderant CD45R+CD127- population and a smaller CD45R-CD127+ population. Analysis of gene expression was employed to understand the relationship between the DN1 CD117+ (DN1 CD117) and the DN1 CD45R+ (DN1 CD45R) populations. Expression of genes associated with the T-cell lineage, such as Notch-1, Runx-1 and Rag-1 was observed in both populations. Furthermore, substantial expression levels of genes involved in T-cell commitment, such as pre-Ta, in the DN1 CD45R population could reflect the initiation of T-cell fate specification. In parallel, a Cre recombinase based lineage tracing approach was utilised to further dissect the earliest thymocyte pools. Upon expression of the Cre recombinase, all cells and their progeny are permanently marked by the expression of a fluorescent reporter protein. In this study, the human CD2 (hCD2) promoter and locus control regions drove expression of the Cre recombinase. Analysis of the DN1 population revealed that nearly all the DN1 CD117 fraction was reporter negative, whereas the DN1 CD45R subset was completely reporter positive. Since expression of hCD2 has so far been reported only in the lymphoid lineage, this observation further underlines the fundamental differences between the two progenitor fractions and indicates their alternate developmental origins. To address the developmental potential of these populations, the DN1 CD117 and the DN1 CD45R pools were functionally assessed in vitro and in vivo. The DN1 CD117 population showed a robust T-, B- and NK-cell potential in vitro and in vivo, in addition to a residual myeloid activity in vivo, whereas the DN1 CD45R fraction was strongly biased towards a CD8 NK-T cell lineage in vivo. In summary, these data indicate that developmentally distinct progenitor populations seed the adult murine thymus and can potentially contribute to discrete subsets of mature haematopoietic cells.
10

Molecular and functional characterisation of dendritic cells derived from the MUTZ-3 acute myeloid leukaemia

Rasaiyaah, Jane January 2009 (has links)
Dendritic Cells (DC) are a group of professional antigen presenting cells that act as sentinels for the body's defense system against microbial pathogens. DC respond to local signals from invading pathogens, by migrating to lymph nodes or spleen, and there activating T-cell dependent antigen-specific immune responses. Both quantitative and qualitative parameters of the immune response depend critically on signals given out by DC. These signals, in turn, depend on complex signal transduction pathways triggered in the DC by exposure to different types of microbes. These pathways are engaged by pattern recognition receptors such as Toll-like receptors (TLRs) and various sugar-binding receptors. The integration of DC signalling pathways, and how this controls the eventual type of T cell response remains a central question of immunology. The thesis focuses on the characterisation of the MUTZ-3 cell line as a DC model. The MUTZ-3 acute myeloid leukaemia cell line has previously been proposed as a useful in vitro model for DC. The cell line is not homogenous and contains a mixture of different differentiation stages. The first results chapter focuses on optimisation of DC differentiation and purification in this model, as well as the activation using different TLRs. The second focuses on the analysis and validation of base line array data comparing the MUTZ-3 cells to DC. Gene expression analysis revealed differences between M3DC and MDDC, amounting to over 5% of the transcriptome. The differentially expressed genes were enriched with functional cluster representing cellular responses to external stimuli. The role of mixed linage kinases (MLK) in DC signalling forms the final results chapter. It has been observed that a small molecular weight inhibitor of MLK blocks DC maturation in response to some ligands but not others. MLK may therefore be an interesting surrogate for DC activation. This chapter investigates the role of MLKs in MUTZ-3 using protein inhibitors, RNAi and dominant negative mutants.

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