OUTER MEMBRANE VESICLES INTEGRITY IS ESSENTIAL FOR THE INDUCTION OF ADEQUATE PROTECTIVE CAPACITY AGAINST PERTUSSIS

ZURITA MARÍA EUGENIA; SOL BRAVO; GAILLARD MARÍA EMILIA; DANIELA HOZBOR

Brusellas

Simposio; 12th International Bordetella symposium in Brussels.; 2019

We have designed and characterized with very good results a novel pertussis vaccine candidate based onouter membrane vesicles (OMVs). OMVs are nanosized lipid vesicles that contain proteins, lipids,pep#doglycan and toxins. We detected that OMVs from B. pertussis are highly immunogenic, inexpensiveto produce and very stable. Here, we analyze the contribu#on of the integrity of OMVs on theirimmunogenic and protec#ve capacity against pertussis. The rupture of the OMVs was carried outmechanically using a Ribolyser Sample Homogenizer. The loss of the OMVs integrity was confirmed bytransmission electron microscopy and dynamic light scaEering technique. By SDS-PAGE we detected thatthe protein and LPS electrophore#c profiles of ribolyser-treated OMVs were similar to those observed fornon-treated OMVs. By performing a compara#ve study with non-treated OMVs, we demonstrated in micethat ribolyser-treated OMVs exhibited lower protected capacity against sublethal B. pertussis infec#ons.Indeed, the B. pertussis loads were significantly increased in the lungs of ribolyser-treated OMVsvaccinated animals, with the CFUs recovered being increased by 2 log units above those detected in thenon-treated OMVs immunized animals, (p0.001). We also detected that ribolyser-treated OMVs inducedlower levels IgG an#bodies against B. pertussis whole-cell lysates (ribolyser-treated OMVs: 123.25 ± 25.19vs non-treated OMVs: 303.8 ± 71.20). Of interest was that the ribolyser-treated OMVs generated sera withlower bactericidal capabili#es (% bacterial survival: 98.16 %) than that detected with the non-treatedOMVs-induced sera (% bacterial survival: 61.5 %), sugges#ng that those ac#vi#es were involved in theclearance of B. pertussis. Finally, by performing experiments combining OMVs with an unrelated an#gen,we demonstrated that ribolyser-treated OMVs has a reduced adjuvant capacity in comparison with nontreated OMVs. All the results presented here point out the relevance of OMVs integrity for itsimmunogenic capacity.