title: Anti-MrkA Monoclonal Antibodies Reveal Distinct Structural and Antigenic Features of MrkA.
abstract: Antibody therapy against antibiotics resistant Klebsiella pneumoniae infections represents a promising strategy, the success of which depends critically on the ability to identify appropriate antibody targets. Using a target-agnostic strategy, we recently discovered MrkA as a potential antibody target and vaccine antigen. Interestingly, the anti-MrkA monoclonal antibodies isolated through phage display and hybridoma platforms all recognize an overlapping epitope, which opens up important questions including whether monoclonal antibodies targeting different MrkA epitopes can be generated and if they possess different protective profiles. In this study we generated four anti-MrkA antibodies targeting different epitopes through phage library panning against recombinant MrkA protein. These anti-MrkA antibodies elicited strong in vitro and in vivo protections against a multi-drug resistant Klebsiella pneumoniae strain. Furthermore, mutational and epitope analysis suggest that the two cysteine residues may play essential roles in maintaining a MrkA structure that is highly compacted and exposes limited antibody binding/neutralizing epitopes. These results suggest the need for further in-depth understandings of the structure of MrkA, the role of MrkA in the pathogenesis of Klebsiella pneumoniae and the protective mechanism adopted by anti-MrkA antibodies to fully explore the potential of MrkA as an efficient therapeutic target and vaccine antigen.
authors.affiliation: Dept. of Infectious Disease and Vaccines, MedImmune, Gaithersburg, MD, United States of America.
authors.forename: Qun
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Dept. of Antibody Discovery and Protein Engineering, MedImmune, Gaithersburg, MD, United States of America.
authors.forename: Yan
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Dept. of Infectious Disease and Vaccines, MedImmune, Gaithersburg, MD, United States of America.
authors.forename: Romana
authors.initials: R
authors.lastname: Cvitkovic
authors.affiliation: Dept. of Infectious Disease and Vaccines, MedImmune, Gaithersburg, MD, United States of America.
authors.forename: Meghan E
authors.initials: ME
authors.lastname: Pennini
authors.affiliation: Dept. of Antibody Discovery and Protein Engineering, MedImmune, Gaithersburg, MD, United States of America.
authors.forename: Chew Shun
authors.initials: CS
authors.lastname: Chang
authors.affiliation: Dept. of Infectious Disease and Vaccines, MedImmune, Gaithersburg, MD, United States of America.
authors.forename: Mark
authors.initials: M
authors.lastname: Pelletier
authors.affiliation: Dept. of Infectious Disease and Vaccines, MedImmune, Gaithersburg, MD, United States of America.
authors.forename: Jessica
authors.initials: J
authors.lastname: Bonnell
authors.affiliation: Dept. of Antibody Discovery and Protein Engineering, MedImmune, Gaithersburg, MD, United States of America.
authors.forename: Adem C
authors.identifier: http://orcid.org/0000-0002-3163-7421
authors.initials: AC
authors.lastname: Koksal
authors.affiliation: Dept. of Antibody Discovery and Protein Engineering, MedImmune, Gaithersburg, MD, United States of America.
authors.forename: Herren
authors.initials: H
authors.lastname: Wu
authors.affiliation: Dept. of Antibody Discovery and Protein Engineering, MedImmune, Gaithersburg, MD, United States of America.
authors.forename: William F
authors.initials: WF
authors.lastname: Dall'Acqua
authors.affiliation: Dept. of Infectious Disease and Vaccines, MedImmune, Gaithersburg, MD, United States of America.
authors.forename: C Kendall
authors.initials: CK
authors.lastname: Stover
authors.affiliation: Dept. of Antibody Discovery and Protein Engineering, MedImmune, Gaithersburg, MD, United States of America.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Xiao
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology*; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000942:Antigens, Bacterial / Q000276:immunology*; D024901:Drug Resistance, Multiple, Bacterial / Q000276:immunology; D000939:Epitopes / Q000276:immunology; D005434:Flow Cytometry; D007368:Interferometry; D007710:Klebsiella Infections / Q000276:immunology; D007711:Klebsiella pneumoniae / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D011994:Recombinant Proteins
chemical_list: D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D000939:Epitopes; D011994:Recombinant Proteins