Abstract
Genetically modified dendritic cell (DC)-based vaccines have not been explored for immunization against tuberculosis. A gene-modified DC vaccine expressing Mycobacterium tuberculosis (M.tb) antigen 85A (Ag85A) was developed by using a recombinant replication-deficient adenoviral gene transfer vector (AdAg85A). AdAg85A-transduced DC vaccine (AdAg85/ DC) expressed higher levels of IL-12 and was much more immunogenic than Ag85 protein-loaded (pro/DC) or CD4/CD8 T cell peptide-loaded (pep/DC) DC vaccines. Compared to pro/DC or pep/DC, AdAg85/DC elicited a remarkably higher level of ex vivo IFN-γ production by CD4 and CD8 T cells at weeks 2, 6, and 12 postimmunization, which was coupled with higher frequencies of antigen-specific T cells. By an in vivo CD8 or CD4 T cell cytotoxicity (CTL) assay, AdAg85/DC was shown to provoke much higher and more sustained levels of CD8 and CD4 CTL activity up to 12 weeks postimmunization. Intramuscular (im) AdAg85/DC immunization was more potent than the iv route of AdAg85/DC immunization. Such stronger immunogenicity of im AdAg85/DC vaccination was corroborated with better protection from M.tb challenge. Our results thus suggest that genetically modified DC-based TB vaccine is superior to subunit DC vaccines and has the potential for therapeutic applications.
| Original language | English |
|---|---|
| Pages (from-to) | 766-775 |
| Number of pages | 10 |
| Journal | Molecular Therapy |
| Volume | 13 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - Apr 2006 |
| Externally published | Yes |
Bibliographical note
Funding Information:Mice and reagents. Six-to ten-week-old female Balb/c mice were purchased from Harlan Laboratories (Indianapolis, IN, USA). The animals were housed in a specific-pathogen-free facility in the Central Animal Facility at McMaster University and cared for in accordance with the McMaster Animal Research Ethics Board. The construction and amplification of a replication-deficient (E1/E3-deleted) recombinant adenovirus encoding the gene for antigen 85A has recently been described [23] and it was used to transduce bone marrow-derived dendritic cells. An adenoviral vector (Addl70-3) was used as control (the replication-deficient adenovirus that does not express any foreign gene). All viruses were purified and stored at −70°C until needed. Purified M.tb antigen 85 complex protein was provided by Colorado State University through funds from the National Institute of Allergy and Infectious Diseases (Contract 1-AI-75320). Two synthetic Ag85A peptides specific for Balb/c background mice (H-2d) were used. The MHC class I-specific peptide (MPVGGQSSF) and the MHC class II-specific peptide (LTSELPGWLQANRHVKPTGS) [24] were synthesized by Dalton Chemical Laboratories (Toronto, ON, Canada). As control peptides, the H-2d-restricted peptide from β-galactosidase876–884 (TPHPARIGL) was used for CD8 CTL experiments, and I-Ad-restricted ovalbumin peptide (OVA323–339; ISQAVHAAHAEINEAGR) was used for CD4 CTL experiments. All proteins were dissolved in dimethyl sulfoxide and stored at −20°C until needed.
Funding Information:
The authors are grateful to Anna Zganiacz, Duncan Chong, and Xueya Feng for their technical assistance and Dr. LinMing Liu for her helpful advice. This study is supported by funds from the Canadian Institutes for Health Research.
ASJC Scopus Subject Areas
- Molecular Medicine
- Molecular Biology
- Genetics
- Pharmacology
- Drug Discovery
