Studies on the synergistic protective activity of cancer antigens associated to engineered bacterial Outer Membrane Vesicles

Introduction Bacterial Outer Membrane Vesicles (OMVs) are naturally produced by all Gram-negative bacteria and are emerging as an attractive vaccine platform. The exploitation of OMVs in cancer immunotherapy was tested by decorating them with cancer epitopes and by following their capacity to elicit protective immune responses, alone or in combination, using cancer mouse models. Furthermore, we tested whether cancer cell-derived exosomes (TEXs) and OMVs can form complexes and whether such complexes, which carry TEX- associated tumor antigens and OMV-associated immune-stimulatory molecules, elicit anti-tumor immune responses in vivo. Results Immunization with OMVs engineered with two B cell epitopes (EGFRvIII and D8-mFAT1) induced tumor growth inhibition after mouse challenge with cell lines expressing the corresponding epitopes. Furthermore, mice immunized with engineered OMVs carrying two cancer epitopes, the EGFRvIII B cell epitope and the M30 CD4+ T cell epitope, were completely protected from EGFRvIIIB16F10 cell line expressing both epitopes, indicating the importance of multi-antigen immunization in cancer immunotherapy. Furthermore TEXs- OMVs immunization induced antibody responses against exosome antigens with a Th1-type profile. Finally, the combination of CT26-derived TEXs and MBP-D8-mFAT1 OMVs elicited synergistic protective activity against mouse challenge with CT26 cell line. Conclusions OMVs decorated with tumor antigens elicit antigen-specific, protective anti- tumor responses in mice. The synergistic protective activity of multiple epitopes simultaneously administered with OMVs, either by direct OMV engineering or by TEX-OMV combination, demonstrates the attractiveness of the OMV platform in cancer immunotherapy.

Grantor dc:publisher

Università degli studi di Trento

Year dc:date

2017

Author dc:creator

• Ganfini, Luisa

Contributors dc:contributor

• Grandi, Guido

• Settore BIO/19 - Microbiologia Generale

Statement dc:rights

• info:eu-repo/semantics/openAccess
• license:Tutti i diritti riservati (All rights reserved)
• license uri:iris.PRI01

Language dc:language

eng

Identifier

http://dx.doi.org/10.15168/11572_368961
10.15168/11572_368961

OAI identifier oai:identifier

oai:iris.unitn.it:11572/368961