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

Despite advances in therapies, bacterial chronic respiratory infections persist as life-threatening to patients suffering from cystic fibrosis (CF). Pseudomonas aeruginosa and bacteria of the Burkholderia cepacia complex are among the most difficult of these infections to treat, due to factors like their resistance to multiple antibiotics and ability to form biofilms. The lack of effective antimicrobial strategies prompted our search for alternative immunotherapies that can effectively control and reduce those infections among CF patients. Previous work from our group showed that the anti-BCAL2645 goat polyclonal antibody strongly inhibited Burkholderia cenocepacia to adhere and invade cultured epithelial cells. In this work, we showed that the polyclonal antibody anti-BCAL2645 also strongly inhibited the ability of P. aeruginosa to form biofilms, and to adhere and invade the human bronchial epithelial cell line CFBE41o-. The polyclonal antibody also inhibited, to a lesser extent, the ability of B. multivorans to adhere and invade the human bronchial epithelial cell line CFBE41o. We also show that the ability of B. cenocepacia , P. aeruginosa and B. multivorans to kill larvae of the Galleria mellonella model of infection was impaired when bacteria were incubated with the anti-BCAL2645 antibody prior to the infection. Our findings show that an antibody against BCAL2645 possesses a significant potential for the development of new immunotherapies against these three important bacterial species capable of causing devastating and often lethal infections among CF patients.