Burkholderia cenocepacia BCAM2418‐induced antibody inhibits bacterial adhesion, confers protection to infection and enables identification of host glycans as adhesin targets

Abstract

Trimeric Autotransporter Adhesins (TAA) found in Gram-negative bacteria play a key role in virulence. This is the case of Burkholderia cepacia complex (Bcc), a group of related bacteria able to cause infections in patients with cystic fibrosis. These bacteria use TAAs, among other virulence factors, to bind to host protein receptors and their carbohydrate ligands. Blocking such contacts is an attractive approach to inhibit Bcc infections. In this study, using an antibody produced against the TAA BCAM2418 from the epidemic strain Burkholderia cenocepacia K56-2, we were able to uncover its roles as an adhesin and the type of host glycan structures that serve as recognition targets. The neutralisation of BCAM2418 was found to cause a reduction in the adhesion of the bacteria to bronchial cells and mucins. Moreover, in vivo studies have shown that the anti-BCAM2418 antibody exerted an inhibitory effect during infection in Galleria mellonella. Finally, inferred by glycan arrays, we were able to predict for the first time, host glycan epitopes for a TAA. We show that BCAM2418 favoured binding to 3 0 sialyl-3-fucosyllactose, histo-blood group A, α-(1,2)-linked Fuccontaining structures, Lewis structures and GM1 gangliosides. In addition, the glycan microarrays demonstrated similar specificities of Burkholderia species for their most intensely binding carbohydrates. K E Y W O R D S adhesin antibody, Burkholderia cepacia complex, host glycans as adhesin targets, trimeric autotransporter adhesins 1 | INTRODUCTION Members of the denominated Burkholderia cepacia complex (Bcc; group of 22 species), can cause severe infections in humans and animals (Scoffone et al., 2017). Among those, Burkholderia cenocepacia and Burkholderia multivorans are particularly dangerous for cystic fibrosis (CF) patients (Scoffone et al., 2017). They are highly adapted

Identification by Reverse Vaccinology of Three Virulence Factors in Burkholderia cenocepacia That May Represent Ideal Vaccine Antigens

“…Among them, BCAM0949, BCAM2418, BCAS0409 and BCAS0236 were previously described as being involved in virulence and cell adhesion [ 25 , 59 , 60 , 61 ]. BCAS0147 was described as surface exposed [ 21 ]; BCAM1514 and BCAS0409 were localized in the outer membrane fraction in the CF niche [ 62 ].…”

A Polyclonal Antibody against a Burkholderia cenocepacia OmpA-like Protein Strongly Impairs Pseudomonas aeruginosa and B. multivorans Virulence

“…Galleria mellonella killing assays were carried out based on methods already described [ 30 , 31 ] with slight modifications. After bacterial growth, bacterial cultures were measured at OD 640 , and the appropriate volume was collected and washed with PBS 1×.…”

Immunization and Immunotherapy Approaches against Pseudomonas aeruginosa and Burkholderia cepacia Complex Infections

“…Recently, Pimenta et al (2021) described the use of an antibody-mediated passive protection (where an antibody against an antigen from the bacteria is used as a therapy), negatively affecting the infection process an allowing the host immune system to deal with the pathogen [ 87 ]. In this study a polyclonal goat antibody from a trimeric autotransporter adhesin (TAA) from B .…”

“…cenocepacia J2315, while no protection was observed against B . multivorans VC13401, Burkholderia contaminans IST408 and Escherichia coli BL21-DE3 [ 87 ].…”