{"id":{"repo_id":"dundee","oai_identifier":"oai:discovery.dundee.ac.uk:studenttheses/93d42a43-7c3c-4d6e-b69a-27cb4673c1db"},"canonical_url":"https://search.dev.ndltd.org/etd/dundee/oai:discovery.dundee.ac.uk:studenttheses/93d42a43-7c3c-4d6e-b69a-27cb4673c1db","repository":{"repo_id":"dundee","name":"University of Dundee","base_url":"https://discovery.dundee.ac.uk/ws/oai"},"display":{"title":"Role of Siglec-7 in ganglioside recognition and modulating NK cell biology","abstract":"<p>Sialic acid binding Ig-like lectin-7 (Siglec-7), expressed primarily on NK cells,<br/> binds preferentially to alpha2,8 linked disialic acids such as present in the<br/> ganglioside GD3 that is upregulated in certain cancers. Siglec-7 is classified as<br/> an inhibitory receptor as it contains immunoreceptor tyrosine based inhibitory<br/> motifs. It has been shown to inhibit NK cytotoxicity in cellular assays thereby<br/> implying a role for it in NK cell mediated tumour surveillance.<br/> The aim of this project was to study factors affecting ligand recognition by<br/> Siglec-7 and its impact on NK cell functions. An investigation into the<br/> mechanism by which Siglec-7 mediates inhibitory signals to regulate NK cell<br/> biology was also carried out. Recognition of Siglec-7 for GD3 has been reported<br/> to be altered in the presence of complex gangliosides. This project was initiated<br/> with an aim to examine the role of such cis-interactions between GD3 and other<br/> gangliosides such as GM1 in biological systems and thereby its impact on NK<br/> cell biology. B16 (78) cell line was genetically modified to over-express both<br/> GD3 and GM1.<br/> This model system was then analysed using Siglec-7-Fc precomplexes for the<br/> recognition of GD3. Siglec-7-Fc binding of B16 (78) cells with high expression<br/> of GD3 and GM1 was significantly lower compared to cells having high<br/> expression of GD3 and low expression of GM1. However further investigation<br/> of these cis-interactions by confocal microscopy revealed that only less than 3%<br/> of the cells had patches of co-localization of the two gangliosides. Such lateral<br/> segregation of co-expressed GD3 and GM1 was also observed in another cell<br/> line model. Next, an investigation into the role of GD3 in modulating NK cell<br/> functions via Siglec-7 was carried out. Primary PBMCs and a Siglec-7 deficient<br/> NK cell line, NK92, were used for this purpose. The data obtained showed that<br/> Siglec-7 could negatively modulate NK cytotoxicity towards targets expressing<br/> disialylated ligands such as GD3. Furthermore Siglec-7 was also able to<br/> modulate integrin functions on NK cells. LFA-1 mediated adhesion of effectors<br/> to ICAM-1-Fc coated plates and the polarization of perforin granules to ICAM-1-<br/> Fc coated beads were negatively affected by the expression of Siglec-7 in the<br/> NK92 cell line. Biochemical analysis of LFA-1 mediated signalling in NK92 cells<br/> showed negative regulation of Src kinase activation, in an Siglec-7 dependent<br/> manner. Overall these findings suggest a role for Siglec-7 in modulating NK cell<br/> recognition of tumours with aberrant glycosylation patterns. They also form the<br/> basis of further investigation into the mechanisms of inhibitory signalling<br/> mediated by Siglec-7 and could therefore be of potential clinical relevance in NK<br/> cell mediated tumour clearance.</p>","abstract_html":"&lt;p&gt;Sialic acid binding Ig-like lectin-7 (Siglec-7), expressed primarily on NK cells,&lt;br/&gt; binds preferentially to alpha2,8 linked disialic acids such as present in the&lt;br/&gt; ganglioside GD3 that is upregulated in certain cancers. Siglec-7 is classified as&lt;br/&gt; an inhibitory receptor as it contains immunoreceptor tyrosine based inhibitory&lt;br/&gt; motifs. It has been shown to inhibit NK cytotoxicity in cellular assays thereby&lt;br/&gt; implying a role for it in NK cell mediated tumour surveillance.&lt;br/&gt; The aim of this project was to study factors affecting ligand recognition by&lt;br/&gt; Siglec-7 and its impact on NK cell functions. An investigation into the&lt;br/&gt; mechanism by which Siglec-7 mediates inhibitory signals to regulate NK cell&lt;br/&gt; biology was also carried out. Recognition of Siglec-7 for GD3 has been reported&lt;br/&gt; to be altered in the presence of complex gangliosides. This project was initiated&lt;br/&gt; with an aim to examine the role of such cis-interactions between GD3 and other&lt;br/&gt; gangliosides such as GM1 in biological systems and thereby its impact on NK&lt;br/&gt; cell biology. B16 (78) cell line was genetically modified to over-express both&lt;br/&gt; GD3 and GM1.&lt;br/&gt; This model system was then analysed using Siglec-7-Fc precomplexes for the&lt;br/&gt; recognition of GD3. Siglec-7-Fc binding of B16 (78) cells with high expression&lt;br/&gt; of GD3 and GM1 was significantly lower compared to cells having high&lt;br/&gt; expression of GD3 and low expression of GM1. However further investigation&lt;br/&gt; of these cis-interactions by confocal microscopy revealed that only less than 3%&lt;br/&gt; of the cells had patches of co-localization of the two gangliosides. Such lateral&lt;br/&gt; segregation of co-expressed GD3 and GM1 was also observed in another cell&lt;br/&gt; line model. Next, an investigation into the role of GD3 in modulating NK cell&lt;br/&gt; functions via Siglec-7 was carried out. Primary PBMCs and a Siglec-7 deficient&lt;br/&gt; NK cell line, NK92, were used for this purpose. The data obtained showed that&lt;br/&gt; Siglec-7 could negatively modulate NK cytotoxicity towards targets expressing&lt;br/&gt; disialylated ligands such as GD3. Furthermore Siglec-7 was also able to&lt;br/&gt; modulate integrin functions on NK cells. LFA-1 mediated adhesion of effectors&lt;br/&gt; to ICAM-1-Fc coated plates and the polarization of perforin granules to ICAM-1-&lt;br/&gt; Fc coated beads were negatively affected by the expression of Siglec-7 in the&lt;br/&gt; NK92 cell line. Biochemical analysis of LFA-1 mediated signalling in NK92 cells&lt;br/&gt; showed negative regulation of Src kinase activation, in an Siglec-7 dependent&lt;br/&gt; manner. Overall these findings suggest a role for Siglec-7 in modulating NK cell&lt;br/&gt; recognition of tumours with aberrant glycosylation patterns. They also form the&lt;br/&gt; basis of further investigation into the mechanisms of inhibitory signalling&lt;br/&gt; mediated by Siglec-7 and could therefore be of potential clinical relevance in NK&lt;br/&gt; cell mediated tumour clearance.&lt;/p&gt;","abstract_has_math":false,"creators":["Mohan, Bindu"],"institution":"University of Dundee","degree_name":"Doctor of Philosophy","degree_level":"Doctoral Thesis","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Crocker, Paul"],"committee_chairs":[],"committee_members":[],"year":2013,"date_issued":"2013","date_published":"2013","updated_at":"2026-07-24T02:07:52Z","subjects":[],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["oai:discovery.dundee.ac.uk:studenttheses/93d42a43-7c3c-4d6e-b69a-27cb4673c1db"],"render_values":[{"text":"oai:discovery.dundee.ac.uk:studenttheses/93d42a43-7c3c-4d6e-b69a-27cb4673c1db","href":null,"code":true}]}]},"links":{"outbound_url":"https://discovery.dundee.ac.uk/en/studentTheses/93d42a43-7c3c-4d6e-b69a-27cb4673c1db","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Crocker, Paul"]},{"key":"dc:creator","label":"Author","values":["Mohan, Bindu"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2013"]},{"key":"dc:date.issued","label":"Date","values":["2013"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Dundee"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["https://discovery.dundee.ac.uk/en/studentTheses/93d42a43-7c3c-4d6e-b69a-27cb4673c1db"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Doctoral Thesis"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["Doctor of Philosophy"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights.embargodate","label":"Dc Rights Embargodate","values":["2015-02-28"]},{"key":"dc:rights.embargoreason","label":"Dc Rights Embargoreason","values":["/dk/atira/pure/core/document/studentthesisembargoreason/commercialexploitation"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["oai:discovery.dundee.ac.uk:studenttheses/93d42a43-7c3c-4d6e-b69a-27cb4673c1db","https://discovery.dundee.ac.uk/en/studentTheses/93d42a43-7c3c-4d6e-b69a-27cb4673c1db"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://discovery.dundee.ac.uk/files/4026565/Mohan_phd_2013.pdf"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["<p>Sialic acid binding Ig-like lectin-7 (Siglec-7), expressed primarily on NK cells,<br/> binds preferentially to alpha2,8 linked disialic acids such as present in the<br/> ganglioside GD3 that is upregulated in certain cancers. Siglec-7 is classified as<br/> an inhibitory receptor as it contains immunoreceptor tyrosine based inhibitory<br/> motifs. It has been shown to inhibit NK cytotoxicity in cellular assays thereby<br/> implying a role for it in NK cell mediated tumour surveillance.<br/> The aim of this project was to study factors affecting ligand recognition by<br/> Siglec-7 and its impact on NK cell functions. An investigation into the<br/> mechanism by which Siglec-7 mediates inhibitory signals to regulate NK cell<br/> biology was also carried out. Recognition of Siglec-7 for GD3 has been reported<br/> to be altered in the presence of complex gangliosides. This project was initiated<br/> with an aim to examine the role of such cis-interactions between GD3 and other<br/> gangliosides such as GM1 in biological systems and thereby its impact on NK<br/> cell biology. B16 (78) cell line was genetically modified to over-express both<br/> GD3 and GM1.<br/> This model system was then analysed using Siglec-7-Fc precomplexes for the<br/> recognition of GD3. Siglec-7-Fc binding of B16 (78) cells with high expression<br/> of GD3 and GM1 was significantly lower compared to cells having high<br/> expression of GD3 and low expression of GM1. However further investigation<br/> of these cis-interactions by confocal microscopy revealed that only less than 3%<br/> of the cells had patches of co-localization of the two gangliosides. Such lateral<br/> segregation of co-expressed GD3 and GM1 was also observed in another cell<br/> line model. Next, an investigation into the role of GD3 in modulating NK cell<br/> functions via Siglec-7 was carried out. Primary PBMCs and a Siglec-7 deficient<br/> NK cell line, NK92, were used for this purpose. The data obtained showed that<br/> Siglec-7 could negatively modulate NK cytotoxicity towards targets expressing<br/> disialylated ligands such as GD3. Furthermore Siglec-7 was also able to<br/> modulate integrin functions on NK cells. LFA-1 mediated adhesion of effectors<br/> to ICAM-1-Fc coated plates and the polarization of perforin granules to ICAM-1-<br/> Fc coated beads were negatively affected by the expression of Siglec-7 in the<br/> NK92 cell line. Biochemical analysis of LFA-1 mediated signalling in NK92 cells<br/> showed negative regulation of Src kinase activation, in an Siglec-7 dependent<br/> manner. Overall these findings suggest a role for Siglec-7 in modulating NK cell<br/> recognition of tumours with aberrant glycosylation patterns. They also form the<br/> basis of further investigation into the mechanisms of inhibitory signalling<br/> mediated by Siglec-7 and could therefore be of potential clinical relevance in NK<br/> cell mediated tumour clearance.</p>"]},{"key":"dc:title","label":"Title","values":["Role of Siglec-7 in ganglioside recognition and modulating NK cell biology"]}]}],"canonical_facts":{"dc:contributor.advisor":["Crocker, Paul"],"dc:creator":["Mohan, Bindu"],"dc:date":["2013"],"dc:date.issued":["2013"],"dc:description.abstract":["<p>Sialic acid binding Ig-like lectin-7 (Siglec-7), expressed primarily on NK cells,<br/> binds preferentially to alpha2,8 linked disialic acids such as present in the<br/> ganglioside GD3 that is upregulated in certain cancers. Siglec-7 is classified as<br/> an inhibitory receptor as it contains immunoreceptor tyrosine based inhibitory<br/> motifs. It has been shown to inhibit NK cytotoxicity in cellular assays thereby<br/> implying a role for it in NK cell mediated tumour surveillance.<br/> The aim of this project was to study factors affecting ligand recognition by<br/> Siglec-7 and its impact on NK cell functions. An investigation into the<br/> mechanism by which Siglec-7 mediates inhibitory signals to regulate NK cell<br/> biology was also carried out. Recognition of Siglec-7 for GD3 has been reported<br/> to be altered in the presence of complex gangliosides. This project was initiated<br/> with an aim to examine the role of such cis-interactions between GD3 and other<br/> gangliosides such as GM1 in biological systems and thereby its impact on NK<br/> cell biology. B16 (78) cell line was genetically modified to over-express both<br/> GD3 and GM1.<br/> This model system was then analysed using Siglec-7-Fc precomplexes for the<br/> recognition of GD3. Siglec-7-Fc binding of B16 (78) cells with high expression<br/> of GD3 and GM1 was significantly lower compared to cells having high<br/> expression of GD3 and low expression of GM1. However further investigation<br/> of these cis-interactions by confocal microscopy revealed that only less than 3%<br/> of the cells had patches of co-localization of the two gangliosides. Such lateral<br/> segregation of co-expressed GD3 and GM1 was also observed in another cell<br/> line model. Next, an investigation into the role of GD3 in modulating NK cell<br/> functions via Siglec-7 was carried out. Primary PBMCs and a Siglec-7 deficient<br/> NK cell line, NK92, were used for this purpose. The data obtained showed that<br/> Siglec-7 could negatively modulate NK cytotoxicity towards targets expressing<br/> disialylated ligands such as GD3. Furthermore Siglec-7 was also able to<br/> modulate integrin functions on NK cells. LFA-1 mediated adhesion of effectors<br/> to ICAM-1-Fc coated plates and the polarization of perforin granules to ICAM-1-<br/> Fc coated beads were negatively affected by the expression of Siglec-7 in the<br/> NK92 cell line. Biochemical analysis of LFA-1 mediated signalling in NK92 cells<br/> showed negative regulation of Src kinase activation, in an Siglec-7 dependent<br/> manner. Overall these findings suggest a role for Siglec-7 in modulating NK cell<br/> recognition of tumours with aberrant glycosylation patterns. They also form the<br/> basis of further investigation into the mechanisms of inhibitory signalling<br/> mediated by Siglec-7 and could therefore be of potential clinical relevance in NK<br/> cell mediated tumour clearance.</p>"],"dc:identifier":["oai:discovery.dundee.ac.uk:studenttheses/93d42a43-7c3c-4d6e-b69a-27cb4673c1db","https://discovery.dundee.ac.uk/en/studentTheses/93d42a43-7c3c-4d6e-b69a-27cb4673c1db"],"dc:identifier.uri":["https://discovery.dundee.ac.uk/files/4026565/Mohan_phd_2013.pdf"],"dc:language":["eng"],"dc:publisher.institution":["University of Dundee"],"dc:relation.isreferencedby":["https://discovery.dundee.ac.uk/en/studentTheses/93d42a43-7c3c-4d6e-b69a-27cb4673c1db"],"dc:rights.embargodate":["2015-02-28"],"dc:rights.embargoreason":["/dk/atira/pure/core/document/studentthesisembargoreason/commercialexploitation"],"dc:title":["Role of Siglec-7 in ganglioside recognition and modulating NK cell biology"],"dc:type":["Thesis"],"dc:type.qualificationlevel":["Doctoral Thesis"],"dc:type.qualificationname":["Doctor of Philosophy"]},"updated_at":"2026-07-24T02:07:52Z"}