Role of Bordetella pertussis adenylate cyclase toxin in outer membrane vesicles-mediated immunomodulation of macrophages response

BRUNO BLANCÁ; JIMENA ALVAREZ HAYES; JUAN HILARIO, CAFIERO; MARIA EUGENIA RODRIGUEZ

Buenos Aires

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

Sociedad Argentina de Inmunología

Gram-negative bacteria produce and excrete outer membrane vesicles (OMVs) that play a role in the infection process by carrying and transmitting virulence factors into host cells, eventually modulating host defense response. Bordetella pertussis (Bp), the etiological agent of whopping cough, is a Gram-negative bacterium that can survive and persist inside human macrophages (MΦ). We previously showed that adenylate cyclase toxin (CyaA) is one of the factors that are involved in modulation of inflammatory host response and intracellular bacterial survival. We recently observed that OMVs released from Bp (Bp-OMVs) induce a decrease in MΦ bacterial uptake. However, once inside the cell, Bp persistence is higher in MΦ treated with Bp-OMVs, suggesting that these vesicles might mediate bacterial host defense manipulation. In the present study we evaluated the potential role of CyaA in this immunomodulatory effect of Bp-OMVs and the related increase of intracellular bacterial persistence. To this end THP-1 MΦ were treated with OMVs isolated from a Bp CyaA deficient mutant (Bp∆CyaA-OMVs) or wild type strain (Bp-OMVs) and mRNA was recovered 4 h post-treatment. RT-PCR assays showed that inflammatory cytokine expression, such as IL-8 and TNF-α, was significantly higher in Bp∆CyaA-OMVs treated MΦ (p