Mechanism of Chimeric Vaccine Mediated Immune Suppression of Human Dendritic Cells

<p>Type 1 diabetes mellitus is a chronic inflammatory disease in which insulin producing β-cells of the pancreatic islets are killed by autoreactive cells of the immune system in response to a loss of tolerance. Dendritic cells (DC) interact predominantly with naïve T cells to regulate the delicate balance between immunity and tolerance required to maintain immunological homeostasis. In this dissertation, immature human dendritic cells (iDC) were inoculated with a chimeric fusion protein vaccine containing the pancreatic β-cell auto-antigen proinsulin linked to a mucosal adjuvant the cholera toxin B subunit (CTB-INS). Proteomic analysis of vaccine inoculated DCs revealed strong up-regulation of the tryptophan catabolic enzyme indoleamine 2, 3-dioxygenase (IDO1) shown to be directly linked to CTB-INS-induced DC activation and maturation. Treatment of vaccinated DCs with the pharmacological NF-κB inhibitors ACHP or DHMEQ inhibited IDO1 biosynthesis, suggesting a role for NF-κB signaling in CTB-INS vaccine up-regulation of dendritic cell IDO1. Further, blocking the NF-κB-inducing kinase (NIK) phosphorylation of IKK-α dimers and translocation of p52/RelB complexes to the nucleus with anti-NIK siRNA, significantly inhibited IDO1 expression in human DCs. Chromatin immunoprecipitation (ChIP) analysis, showed that RelB-p52 dimers bound dendritic cell NF-κB consensus sequences in the IDO1 promoter region, demonstrating vaccine stimulation of NF-κB non-canonical pathway activation of IDO1 expression in human DCs in vivo. Addition of the Tumor Necrosis Factor Associated Factors (TRAF) TRAF6 and TRAF 2, 3 blocking peptides to vaccinated DCs dramatically reduced the level of IDO1 biosynthesis and stimulated DC suggesting the vaccine may function in the same signaling pathway as TNFR super-family for the up-regulation of IDO1 biosynthesis in vaccinated dendritic cells. Together, these data confirm CTB-INS vaccine activation of the non-canonical NF-κB signaling pathway TNFR receptor family up-regulation of dendritic cell IDO1 biosynthesis permitting vaccine inhibition of DC maturation leading to the suppression of type 1 diabetes development.</p>

Name thesis:degree_name

Doctor of Philosophy (PhD)

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Basic Sciences

Year

2016

Author dc:creator

• Mbongue, Jacques Christian

Contributors dc:contributor

• Langridge, William H. R.
• De Leon, Marino
• Figueroa, Johnny
• Firek, Anthony
• Khan, Salma
• Tang, Jiping

• Cellular and Molecular Physiology
• Medical Biochemistry
• Medical Cell Biology
• Medical Immunology
• Medical Physiology
• Physiology
• Dendritic Cells; Immunity; Cellular; Cell Differentiation; Diabetes Mellitus; Type 1;
• Immunological Homeostasis; Chimeric Fusion Protein Vaccine; Vaccine inhibitation;

Statement dc:rights

• This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.

Language dc:language

English

Repository record dc:identifier

https://scholarsrepository.llu.edu/etd/348

OAI identifier oai:identifier

oai:scholarsrepository.llu.edu:etd-1347