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Dendritic Cells are Both Targets and Initiators of Peripheral Immune Tolerance to Self

Farkas, Adam (2013) Dendritic Cells are Both Targets and Initiators of Peripheral Immune Tolerance to Self. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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Mucin 1 (MUC1) is a highly glycosylated membrane-bound protein normally expressed on the apical surface of ductal epithelial cells. During malignant transformation MUC1 acts as a Tumor-Associated Antigen (TAA) by virtue of its overexpression, loss of polarity, and hypoglycosylation, allowing for T cell and antibody recognition of cryptic peptide epitopes derived from its extracellular domain. Almost all adenocarcinomas express abnormal MUC1 making it an attractive target for cancer vaccines. However, vaccination of MUC1.Tg mice with a synthetic, unglycosylated MUC1 peptide (MUC1p) that mimics one tumor form of the molecule results in a weak anti-MUC1p immune response. WT mice receiving the same vaccine generate robust immunity to MUC1p, suggesting that it is viewed as a “self” antigen in MUC1.Tg mice, and apparently subject to peripheral tolerance. To globally query these distinct programs of immunity and tolerance induced by MUC1p in WT and MUC1.Tg mice respectively, we conducted whole transcriptome analysis of splenic RNA 24h and 72h after i.v. immunization of both mouse strains with MUC1p. We found that a new cohort of “pancreatic” enzymes (e.g. trypsin and CPB1) were expressed by splenic dendritic cells (DC) and regulated such that immunization with self-antigen suppressed their expression while foreign-antigens induced it within 24h post-vaccination. The relative expression of trypsin and CPB1 was highly correlated with the immunogenicity of the DC. Suppressed expression marked DC that were highly tolerized as demonstrated by low costimulatory molecule expression, limited motility, production of Aldh1/2, and preferential priming of naïve CD4+ T cells into Foxp3+ Treg versus IFNγ+ cells, while enhanced expression identified immunogenic DC. Deficient NFκβ pathway activation and enhanced STAT3 phosphorylation transcriptionally underlie tolerized DC along with sustained expression of zDC. Trypsin was required for efficient degradation of the extracellular matrix, while CPB1 was required by DC to induce optimal, antigen-specific proliferation of CD4+ T cells. Importantly, these vaccine-induced changes in DC phenotype affected the entire splenic DC compartment, revealing an underappreciated role for endogenous DC in the transmission and amplification of vaccine-induced immunity or tolerance. These results underscore the importance of vaccine antigen choice and will contribute to rational vaccine design.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Farkas, Adamamf71@pitt.eduAMF71
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairFinn, Olivera Jojfinn@pitt.eduOJFINN
Committee MemberSalter, Russell Drds@pitt.eduRDS
Committee MemberMorris, Sidney Msmorris@pitt.eduSMORRIS
Committee MemberWatkins, Simon C.swatkins@pitt.eduSWATKINS
Committee MemberLarregina, Adriana Tadrianal@pitt.eduADRIANAL
Date: 12 August 2013
Date Type: Publication
Defense Date: 30 July 2013
Approval Date: 12 August 2013
Submission Date: 9 August 2013
Access Restriction: 1 year -- Restrict access to University of Pittsburgh for a period of 1 year.
Number of Pages: 158
Institution: University of Pittsburgh
Schools and Programs: School of Medicine > Immunology
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: Dendritic Cells, MUC1, Vaccine, Immune Tolerance, Cancer, Pancreatic Enzymes
Date Deposited: 12 Aug 2013 14:01
Last Modified: 15 Nov 2016 14:14


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