Immunization with the novel vaccine candidate based on outer membrane vesicles improve resistance of mice to Bordetella pertussis infection

RUDI, ERIKA; GAILLARD M. EMILIA; DANIELA F. HOZBOR,

Mar del Plata

Congreso; 15.33. LXX Reunión Anual de la Sociedad Argentina de Inmunología (SAI); 2022

Pertussis is a severe respiratory disease that can be fatal, particularly in infants.Despite high vaccine coverage, the disease remains a problem because the currentlyused acellular vaccines (2nd-generation) do not completely prevent infection ortransmission. Because of this, a 3rd-generation of vaccine capable of overcoming theweaknesses of current formulations is needed. Preclinical studies using the intranasal-challenge mice model showed that our vaccine candidate based on outer-membrane-vesicles (OMVvac) is an attractive candidate because of its safety and immunogenicproperties. In this study we evaluated the ability of the OMVvac to prevent B. pertussisnasal colonization (infection). We evaluated 3 doses-OMVvac schemes in 3 differentimmunization routes in Balb/C (Th2/M2-dominant immune response) and C57BL6(Th1/M1-dominant immune response) mice strains: intramuscular (IM); intranasal (IN)and sublingual (SL). After the challenge with sublethal doses of B. pertussis(5x10 7 CFU/40μl) we detected that while in both mice strains SL route did not preventnasal colonization, the use of OMVvac in both IN and IM scheme was capable toreduce nasal bacterial colonization compared to that detected in non-immunizedanimals (p<0.05). In comparison with Balb/C strain, the IN OMVvac immunization inC57BL6 mice was more efficient in controlling nasal colonization (reduction respect tothe control: 1.3 vs 0.58 orders; p<0,05). Of interest, in the C57BL6 mice strain IN routeinduced the highest nasal IgA levels (p<0.05). In both mice strains higher levels of IL-17(C57BL6 IN: 10322pg/ml± 105pg/ml IM: 5821pg/ml± 93pg/ml; Balb/C IN: 10364pg/ml±276 pg/ml IM: 9428 pg/ml± 1012pg/ml) were detected either in IN or IM OMVvacscheme in comparison to those detected in SL route. INF-Ɣ levels were also higher inboth strains for these routes (p<0.05). The results obtained support the use of IN or IMOMVvac scheme to reduce B. pertussis transmission.