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Cationic submicron emulsions for pulmonary DNA immunization
Maytal Bivas-Benita1, Marion Oudshoorn, Stefan Romeijn
1Leiden/Amsterdam Center for Drug Research, Division of Pharmaceutical Technology, P.O. Box 9502, 2300 RA Leiden, The Netherlands. m.bivas@lacdr.leidenuniv.nl
Abstract:
Pulmonary immunization against inhaled pathogens such as Mycobacterium tuberculosis would induce local and systemic immune responses and protect from entry and dissemination of the pathogen. The aim of this study was to evaluate cationic submicron emulsion as a potential carrier for DNA vaccines to the lung. DNA loaded emulsions were 128-152 nm in size and retained positive zeta potential above +40 mV during 3 months of storage. Loading efficiency was above 99%, DNA was protected from DNase I degradation up to 60 min and was stable in presence of 75% fetal calf serum (FCS). The plasmid DNA was detected in the endo-lysosomal compartment of the human bronchial cell line, Calu-3, 6 h after application. No cytotoxic effect on these cells was observed. Human dendritic cells were matured in presence of DNA loaded emulsion, although to a lesser extent than DNA solution indicating slower release and lower exposure to unmethylated CpG sequences. These results indicate that cationic submicron emulsions are potential DNA vaccine carriers to the lung since they are able to transfect pulmonary epithelial cells, which possibly induce cross priming of antigen presenting cells and directly activate dendritic cells, resulting in stimulation of antigen specific T-cells.
Insights
Cationic submicron emulsions effectively deliver DNA vaccines to the lung, enhancing pulmonary immunization. These stable carriers show promise for transfecting lung cells and stimulating immune responses against inhaled pathogens.
Area of Science:
- Nanotechnology
- Immunology
- Vaccinology
Background:
- Pulmonary immunization is crucial for combating inhaled pathogens like Mycobacterium tuberculosis.
- Developing effective delivery systems for lung-based DNA vaccines is essential for inducing robust immune responses.
Purpose of the Study:
- To evaluate cationic submicron emulsions as carriers for DNA vaccines targeting the lung.
- To assess the stability, DNA protection, cellular uptake, and immunomodulatory potential of these emulsions.
Main Methods:
- Characterization of DNA-loaded cationic submicron emulsions (size, zeta potential, loading efficiency).
- Assessment of DNA protection against DNase I and fetal calf serum (FCS).
- In vitro studies using Calu-3 bronchial cells and human dendritic cells to evaluate transfection and maturation.
Main Results:
- Emulsions were 128-152 nm, with a positive zeta potential (>+40 mV) and >99% loading efficiency.
- DNA was protected from degradation and stable in 75% FCS; plasmid DNA was detected in Calu-3 cells within 6 hours with no observed cytotoxicity.
- DNA-loaded emulsions induced dendritic cell maturation, albeit slower than DNA solution, suggesting controlled release.
Conclusions:
- Cationic submicron emulsions are promising carriers for pulmonary DNA vaccination.
- These emulsions can effectively transfect pulmonary epithelial cells and activate dendritic cells, potentially leading to antigen-specific T-cell stimulation.
- This approach may enhance local and systemic immunity against inhaled pathogens.
