Uncovering Novel Mechanism of Immune Modulation of Invariant Natural Killer T Cells By Liposomal Α-Galactosylceramide

<p>Invariant Natural Killer T cells (iNK-T cells) are a powerful regulatory immune cell that can recruit both innate and adaptive immune cells. Unlike conventional T cells (CD4⁺and CD8α⁺), they recognize glycolipid antigens via the MHC-class-I like molecule, CD1d. A synthetically derived glycolipid from the marine sponge, <em>Agelas mauritianus</em>, alpha-Galactosylceramide (α-GalCer) potently activates iNK-T cells. Within a few hours after activation, iNK-T cells produce high quantities of T_H1 and T_H2 type cytokines, thus shape subsequent adaptive immunity towards inflammation (T_H1) or immune-suppression (T_H2). Structural modification of α-GalCer’s phytosphingosine chain, α-GalCer C20:2 has been shown to polarize iNK-T responses towards T_H2 and help treat several autoimmune diseases. Recently, Liposomal formulation of α-GalCer (RGI-2001) has been shown to help ameliorate Graft-Versus-Host-disease (GVHD) via expansion of regulatory T cells. However, molecular and cellular mechanism by which how Liposomal α-GalCer modulate iNK-T responses is unknown. Our preliminary data suggests that both T_H2 biasing α-GalCer C20:2 and Liposomal α-GalCer elicit T_H2 polarized iNK-T responses. We hypothesize Liposomal α-GalCer will display unique antigen uptake, processing and presentation with CD1d similar to known T_H2 biasing α-GalCer analogues, allowing for an immunosuppressive cytokine response, thus reducing pro-inflammatory disease complications. In this study, we investigated the cellular and molecular requirements of CD1d association with Liposomal α-GalCer through various <em>in vitro</em> assays to assess antigen uptake, processing, and presentation to iNK-T cells. We found that Liposomal α-GalCer share kinetics of antigen association with CD1d likely within non-lipid raft domain in the antigen presenting cells, similarly to α-GalCer C20:2, but require cellular internalization for CD1d association, similarly to T_H1 biasing α-GalCer. Our findings suggest that Liposomal aGalCer requires early endosomal recycling for association with CD1d. In the future, we plan to investigate the visual and kinetic sites of α-GalCer:CD1d loading using confocal microscopy, and impact on immunologic synapse formation.</p>

Name thesis:degree_name

Masters of Science (MS)

Level thesis:degree_level

Thesis (MS)

Year dc:date.available

2023

Authors dc:creator

• Flegle, Alexandra S
• <p><a href="http://www.orcid.org/0000-0002-4639-7889" target="_blank" title="http://www.orcid.org/0000-0002-4639-7889 ">http://www.orcid.org/0000-0002-4639-7889</a></p> <p>ID: 0000-0002-4639-7889</p>

Contributors dc:contributor

• Jin Seon Im
• Vahid Afshar-Kharghan
• Greg Lizee

• CD1d restricted-invariant Natural Killer T cells
• α-Galactosylceramide
• liposomes
• synthetic glycolipids
• Immune System Diseases
• Medical Immunology

Repository record dc:identifier

https://digitalcommons.library.tmc.edu/utgsbs_dissertations/1262

OAI identifier oai:identifier

oai:digitalcommons.library.tmc.edu:utgsbs_dissertations-2319