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Blood, 19 March 2009, Vol. 113, No. 12, pp. 2673-2683. Prepublished online as a Blood First Edition Paper on February 4, 2009; DOI 10.1182/blood-2008-04-153536. This Article Full Text Full Text (PDF) All Versions of this Article: blood-2008-04-153536v1 blood-2008-04-153536v2 113/12/2673    most recent Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Rights and Permissions Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Qazi, K. R. Articles by Gabrielsson, S. Search for Related Content PubMed PubMed Citation Articles by Qazi, K. R. Articles by Gabrielsson, S. Related Collections Immunobiology Social Bookmarking                   What's this?  Previous Article  |  Table of Contents  |  Next Article  IMMUNOBIOLOGY Antigen-loaded exosomes alone induce Th1-type memory through a B cell–dependent mechanism Khaleda Rahman Qazi1, Ulf Gehrmann1, Emilie Domange Jordö1, Mikael C. I. Karlsson1, and Susanne Gabrielsson1 1 Department of Medicine, Clinical Allergy Research Unit, Karolinska University Hospital Solna, Stockholm, Sweden Exosomes are nanovesicles harboring proteins important for antigen presentation. We compared the potency of differently loaded exosomes, directly loaded with OVA323-339 peptide (Pep-Exo) or exosomes from OVA-pulsed DCs (OVA-Exo), for their ability to induce specific T-cell proliferation in vitro and in vivo. Both Pep-Exo and OVA-Exo elicited specific transgenic T-cell proliferation in vitro, with the Pep-Exo being more efficient. In contrast, only OVA-Exo induced specific T-cell responses in vivo highlighting the importance of indirect loading strategies in clinical applications. Coadministration of whole OVA overcame the unresponsiveness with Pep-Exo but still elicited a lower response compared with OVA-Exo. In parallel, we found that OVA-Exo not only augmented the specific T-cell response but also gave a Th1-type shift and an antibody response even in the absence of whole OVA. We detected IgG2a and interferon- production from splenocytes showing the capability of exosomes to provide antigen for B-cell activation. Furthermore, we found that B cells are needed for exosomal T-cell stimulation because Bruton tyrosine kinase–deficient mice showed abrogated B- and T-cell responses after OVA-Exo immunization. These findings reveal that exosomes are potent immune regulators and are relevant for the design of vaccine adjuvants and therapeutic intervention strategies to modulate immune responses. CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

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