BP1092, A BORDETELLA PERTUSSIS VIRULENCE REGULATORY PROTEIN INVOLVED IN ADAPTATION TO INTRACELLULAR ENVIRONMENT

DEBANDI M; OSVALDO YANTORNO; CARRICA M; RODRÍGUEZ M E; CANDELA MASSON; LAMBERTI Y

Buenos Aires

Congreso; LXVIII REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE INMUNOLOGÍA (SAI); 2020

SOCIEDAD ARGENTINA DE INMUNOLOGÍA

Bordetella pertussis (Bp), which causes whooping cough, surviveswithin macrophages, and adapts its bacterial proteome during intracellularinfection. Virulence factors play a key role in bacterial persistenceinside the host cell. Transcription of Bp virulence factors arecontrolled by the interrelated two-component systems BvgAS andRisAS. The participation of additional regulatory systems in this processis not clear. The aim of this work was to characterize the contributionof the BP1092 protein, a two-component system histidinekinase overexpressed intracellularly, in virulence factor regulationand intracellular survival.To this end, we constructed a Bp deletion mutant defective inBP1092 (BPΔ1092) and analysed the differential expression ofvirulence factors representative of the virulent (fhaB), intermediate(bipA), and avirulent (vraA, kpsE) phases by qRT-PCR understandard (SS medium) and modulating conditions (SS medium + 50mM). We showed that BpΔ1092, unlike the parental strain (wt), wasunable to downregulate fha and bipA expression in bacteria growingunder modulating conditions, suggesting that this protein is involvedin the transition to the avirulent phase. Accordingly, by mean of microtitercrystal violet assay, we showed that under modulating conditionsBpΔ1092, but not the WT strain, was able to form a biofilm, away of lifestyle mainly dependent of fhaB expression. Interestingly,microscopy and antibiotic protection assays, showed that the lack ofexpression of BP1092 resulted in a decreased survival of Bp insidemacrophages. This result suggests that early events of the intracellularsurvival depend on BP1092 expression. All the data presentedhere were statistically significant with p