INFLAMMASOME ACTIVATION BY BORDETELLA PERTUSSIS OUTER MEMBRANE VESICLES

ELIZAGARAY, MAIA; MORENO G; HOZBOR D; RUMBO M

Bruselas

Simposio; 12 th Bordetella Symposium; 2019

The resurgence of pertussis in different countries has urged the development of new vaccines that couldovercome the weakness of current vaccines. Under this context we have already iden*fied andcharacterized with very good results, a vaccine candidate based on outer membrane vesicles (OMVs).Thinew vaccine has shown to be safe and able to induce protec*on in mice, with a mixed Th1/Th17/Th2profile and a robust an*body response. In this study, we inves*gated the ability of OMVs derived fromBordetella pertussis (Bp-OMVs), to trigger the ac*va*on of inflammasome-dependent pathways. To thisend, we evaluated the secre*on of hIL-1beta, hIL-18 and ASC-speck forma*on acer the treatment of THP-1 cells with different quan**es of Bp-OMVs (5ng-5ug/well). We detected significantly higher levels of hIL-1b and hIL-18 in culture supernatants s*mulated with 200ng Bp-OMV (or more) vs. non-treated THP-1cells (hIL-1b: 452,4±4,6pg/mL vs 4,4±0,5 pg/mL; p≤0,0001), (hIL-18: 2398,0±219,2pg/mL vs203,0±113,1pg/mL; p≤0,0012). For this concentra*on of Bp-OMVs, the ASC-speck forma*on quan*fied bymicroscopy as ASC+/total cells, was 6,8±0,6 vs non-detected value for non-treated THP-1 cells. For thetreatment LPSE.coli (1ug/mL) +DNA (500ng/mL) used as posi*ve control, the ASC-speck forma*on in theTHP-1 cells was 7,3±0,5 ASC+/total cells.We also evaluated the ability of Bp-OMVs to induce pyroptosis intreated THP-1 cells. To this end, LDH ac*vity was measured in cell culture supernatants. The LDH ac*vitymeasured in Bp-OMV s*mulated cells shown 56,3% LDH release vs CTR; p≤0,05 (percentage of the meanvalue of LDH release compared to non-treated cells which was used as a reference value set to 100%). Ourfindings indicate that Bp-OMVs can ac*vate the ASC-dependent inflammasomes, which could be key totrigger the protec*ve immune response exerted by our vaccine candidate.