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Exosomes carrying mycobacterial antigens can protect mice against M ycobacterium tuberculosis infection
Author(s) -
Cheng Yong,
Schorey Jeffery S.
Publication year - 2013
Publication title -
european journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.272
H-Index - 201
eISSN - 1521-4141
pISSN - 0014-2980
DOI - 10.1002/eji.201343727
Subject(s) - biology , microvesicles , antigen , virology , tuberculosis , immunology , mycobacterium tuberculosis , microbiology and biotechnology , microrna , genetics , gene , medicine , pathology
Approximately 2 billion people are infected with M ycobacterium tuberculosis , the etiological agent of tuberculosis ( TB ), and an estimated 1.5 million individuals die annually from TB. Presently, M ycobacterium bovis BCG remains the only licensed TB vaccine; however, previous studies suggest its protective efficacy wanes over time and fails in preventing pulmonary TB . Therefore, a safe and effective vaccine is urgently required to replace BCG or boost BCG immunizations. Our previous studies revealed that mycobacterial proteins are released via exosomes from macrophages infected with M . tuberculosis or pulsed with M . tuberculosis culture filtrate proteins ( CFP ). In the present study, exosomes purified from macrophages treated with M . tuberculosis CFP were found to induce antigen‐specific IFN ‐γ and IL ‐2‐expressing CD 4 + and CD8 + T cells. In exosome‐vaccinated mice, there was a similar T H 1 immune response but a more limited T H 2 response compared to BCG ‐vaccinated mice. Using a low‐dose M . tuberculosis mouse aerosol infection model, exosomes from CFP ‐treated macrophages were found to both prime a protective immune response as well as boost prior BCG immunization. The protection was equal to or superior to BCG . In conclusion, our findings suggest that exosomes might serve as a novel cell‐free vaccine against an M . tuberculosis infection.