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DENDRITIC CELL-SPECIFIC VACCINE UTILIZING ANTIBODY-MIMETIC
LIGAND AND LENTIVECTOR SYSTEM
by
Liang Xiao
A Dissertation Presented to the
FACULTY OF THE USC GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
DOCTOR OF PHILOSOPHY
(CHEMICAL ENGINEERING)
May 2013
Copyright 2013 Liang Xiao
Object Description
| Title | Dendritic cell-specific vaccine utilizing antibody-mimetic ligand and lentivector system |
| Author | Xiao, Liang |
| Author email | liangxia@usc.edu;liangxiaousc@gmail.com |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Chemical Engineering |
| School | Viterbi School of Engineering |
| Date defended/completed | 2013-03-22 |
| Date submitted | 2013-04-09 |
| Date approved | 2013-04-09 |
| Restricted until | 2013-04-09 |
| Date published | 2013-04-09 |
| Advisor (committee chair) | Wang, Pin |
| Advisor (committee member) |
Shing, Katherine Chen, Si-Yi |
| Abstract | Dendritic cell (DC)-based vaccines have shown promise as an immunotherapeutic modality for cancer and infectious diseases in many preclinical studies and clinical trials. Dendritic cells (DCs) are specialized antigen presenting cells (APCs) that can uptake and process antigens for presentation through the major histocompatibility complex (MHC) and activate naïve T cells. Because of this unique biological role, DCs have been widely exploited to develop DC-based vaccines for protective immunity against bacterial, viral, and fungal infections. The development of DC-based vaccines has also been one of the major focuses of cancer immunotherapy. Patient-derived DCs are loaded with tumor antigens and subsequently administered back to the patient. This type of autologous cell therapy led to the first FDA-approved cancer vaccine, sipuleucel-T. However, the tedious procedure for generating the vaccine, its high cost ($93,000 USD) per patient, and only modest improvement in survival (an average of 4.1 months) could limit its extensive application. A better strategy would be direct and specific loading of antigens onto DCs in vivo, which could be achieved by targeting DC-specific cell-surface receptors that facilitate internalization of the bound antigens for antigen presentation. DC-specific ICAM3-grabbing non-integrin (DC-SIGN or CD209) is a promising target for DC- specific antigen delivery because it is predominantly expressed on DCs. In chapter 2, the recombinant extracellular domains (ECD) of human and mouse DC-SIGN (hDC-SIGN and mDC-SIGN) were generated as DC-specific targets for mRNA display. Accordingly, an antibody-mimetic library was constructed by randomizing two exposed binding loops of an expression-enhanced 10th human fibronectin type III domain (e10Fn3). After three rounds of selection against mDC-SIGN, followed by four rounds of selection against hDC-SIGN, we were able to evolve several dual-specific ligands, which could bind to both soluble ECD of human and mouse DC-SIGNs. Using a cell-binding assay, one ligand, eFn-DC6, was found to have high affinity to hDC-SIGN and moderate affinity to mDC-SIGN. When fused with an antigenic peptide, eFn-DC6 could direct the antigen delivery and presentation by human peripheral blood mononuclear cell (PBMC)-derived DCs and stimulate antigen-specific CD8⁺T cells to secrete inflammatory cytokines. In chapter 3, we evaluated dendritic cell (DC)-directed lentiviral vector (DCLV) encoding murine PSCA (DCLV-PSCA) as a novel tumor vaccine for prostate cancer in mouse models. Direct immunization with the DCLV-PSCA in male C57BL/6 mice elicited robust PSCA-responsive CD8⁺ and CD4⁺ T cells in vivo. In a transgenic adenocarcinoma mouse prostate cell line (TRAMP-C1) synergetic tumor model, we further demonstrated that DCLV-PSCA-vaccinated mice could be protected from lethal tumor challenge in a prophylactic model, whereas slower tumor growth was observed in a therapeutic model. In chapter 4, we further improved the immune response of DC-directed lentiviral vaccine by employing a novel TLR4 agonist GLA as adjuvant. Both T cells and B cells responses were greatly enhanced and these improved responses further suppress tumor growth. We also looked at the relationship between the improvement of CD8⁺ T cells and CD4⁺ T cells and which signaling transduction pathway, MyD88 or TRIF, plays a more important role in adjuvant effect. |
| Keyword | dendritic cells; lentivector; vaccine; immunotherapy; cancer; DC-SIGN; antibody; ligand |
| Language | English |
| Part of collection | University of Southern California dissertations and theses |
| Publisher (of the original version) | University of Southern California |
| Place of publication (of the original version) | Los Angeles, California |
| Publisher (of the digital version) | University of Southern California. Libraries |
| Provenance | Electronically uploaded by the author |
| Type | texts |
| Legacy record ID | usctheses-m |
| Contributing entity | University of Southern California |
| Rights | Xiao, Liang |
| Access conditions | The author retains rights to his/her dissertation, thesis or other graduate work according to U.S. copyright law. Electronic access is being provided by the USC Libraries in agreement with the author, as the original true and official version of the work, but does not grant the reader permission to use the work if the desired use is covered by copyright. It is the author, as rights holder, who must provide use permission if such use is covered by copyright. The original signature page accompanying the original submission of the work to the USC Libraries is retained by the USC Libraries and a copy of it may be obtained by authorized requesters contacting the repository e-mail address given. |
| Repository name | University of Southern California Digital Library |
| Repository address | USC Digital Library, University of Southern California, University Park Campus MC 7002, 106 University Village, Los Angeles, California 90089-7002, USA |
| Repository email | cisadmin@usc.edu |
| Archival file | uscthesesreloadpub_Volume7/etd-XiaoLiang-1531.pdf |
Description
| Title | Page 1 |
| Contributing entity | University of Southern California |
| Full text | DENDRITIC CELL-SPECIFIC VACCINE UTILIZING ANTIBODY-MIMETIC LIGAND AND LENTIVECTOR SYSTEM by Liang Xiao A Dissertation Presented to the FACULTY OF THE USC GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY (CHEMICAL ENGINEERING) May 2013 Copyright 2013 Liang Xiao |
