The catecholamine siderophore receptors bfrD and bfrE are required for Bordetella pertussis intramacrophage

CAFIERO, JUAN HILARIO; LAMBERTI, YANINA; ALVAREZ HAYES, JIMENA; RODRIGUEZ, MARIA EUGENIA

Buenos Aires

Congreso; LXIII Argentinean Society for Immunology meeting (SAI), IV LASID meeting, and II French Society for Immunology Meeting; 2015

Sociedad Argentina de Inmunologia

Bordetella pertussis (Bp), the causative agent of whooping cough, survives inside macrophages in compartments which have access to transferrin. A recent proteomic study from our group identified the receptors bfrD and bfrE upregulated during Bp growth inside THP-1 cells. These receptors are involved in the uptake of iron sequestered by catecholamines from transferrin, as demonstrated in B.bronchiseptica. However, the functionality of these receptors was never demonstrated in Bp. In the present study, we first confirmed the upregulation of bfrD in intracellular Bp using a multiple reaction monitoring method. We then constructed both a bfrDE mutant and a complemented strain. These strains were used in an infection assay of PMA differentiated THP-1 cells. Immunofluorescence microscopy showed that there were no differences in the adhesion or the phagocytosis of each strain. The intracellular survival of these strains inside THP-1 cells was analyzed by polymyxin B protection assays, both by CFU counts and FISH staining of intracellular viable bacteria at 3, 24 and 48 hours post infection (pi). The bfrDE mutant strain survived significantly less than the wild type (wt) strain 24 hours pi (p