title: Host resistance to intranasal Acinetobacter baumannii reinfection in mice.
abstract: Acinetobacter baumannii is a major causative agent of healthcare-associated infection and develops multidrug resistance rapidly. However, little is known in the host defense mechanisms against this infection. In this study, we examined if mice recovered from a previous intranasal A. baumannii infection (recovered mice) are fully protected against a subsequent reinfection. We found that, despite the presence of specific serum IgG and mucosal IgA responses prior to the reinfection, the recovered mice were only marginally better protected against intranasal challenge with low doses of homologous or heterologous A. baumannii strains than the naïve mice. Post-challenge immune and inflammatory (cells and cytokines) responses were generally comparable between recovered and naïve mice although the recovered mice produced significantly higher amounts of IFN-γ and IL-17 and had higher percentages and numbers of resident lung CD44(hi)CD62L(-)CD4(+) and CD19(+) B lymphocytes. Taken together, our results suggest that mice recovered from a previous A. baumannii infection remain susceptible to reinfection, indicating the complexity of immune protection mechanism for this Gram-negative, multidrug-resistant emerging pathogen.
authors.affiliation: Human Health Therapeutics, National Research Council Canada, 100 Sussex Drive, Ottawa, ON K1A 0R6, Canada.
authors.forename: Hongyu
authors.initials: H
authors.lastname: Qiu
authors.affiliation: Human Health Therapeutics, National Research Council Canada, 100 Sussex Drive, Ottawa, ON K1A 0R6, Canada.
authors.forename: Zack
authors.initials: Z
authors.lastname: Li
authors.affiliation: Human Health Therapeutics, National Research Council Canada, 100 Sussex Drive, Ottawa, ON K1A 0R6, Canada.
authors.forename: Rhonda
authors.initials: R
authors.lastname: KuoLee
authors.affiliation: Human Health Therapeutics, National Research Council Canada, 100 Sussex Drive, Ottawa, ON K1A 0R6, Canada.
authors.forename: Greg
authors.initials: G
authors.lastname: Harris
authors.affiliation: Human Health Therapeutics, National Research Council Canada, 100 Sussex Drive, Ottawa, ON K1A 0R6, Canada.
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Gao
authors.affiliation: Department of Chemistry, Brock University, St. Catharines, ON L2S 3A1, Canada.
authors.forename: Hongbin
authors.initials: H
authors.lastname: Yan
authors.affiliation: Department of Biological Sciences, California State University, Los Angeles, CA 90032, USA.
authors.forename: H Howard
authors.initials: HH
authors.lastname: Xu
authors.affiliation: Human Health Therapeutics, National Research Council Canada, 100 Sussex Drive, Ottawa, ON K1A 0R6, Canada Department of Biology, Brock University, St. Catharines, ON L2S 3A1, Canada wangxue.chen@nrc.gc.ca.
authors.forename: Wangxue
authors.initials: W
authors.lastname: Chen
mesh_terms: D000191:Actinomycetaceae / Q000276:immunology*; D000193:Actinomycetales Infections / Q000382:microbiology* / Q000401:mortality; D000818:Animals; D058491:Bacterial Load; D060467:Disease Resistance; D054884:Host-Pathogen Interactions / Q000276:immunology*; D051379:Mice; D009666:Nose / Q000382:microbiology*
keywords: Acinetobacter baumannii; host defense; pneumonia; reinfection