Identification of Antigenic Proteins of the Nosocomial Pathogen Klebsiella pneumoniae

Abstract

The continuous expansion of nosocomial infections around the globe has become a precarious situation. Key challenges include mounting dissemination of multiple resistances to antibiotics, the easy transmission and the growing mortality rates of hospital-acquired bacterial diseases. Thus, new ways to rapidly detect these infections are vital. Consequently, researchers around the globe pursue innovative approaches for point-of-care devices. In many cases the specific interaction of an antigen and a corresponding antibody is pivotal. However, the knowledge about suitable antigens is lacking. The aim of this study was to identify novel antigens as specific diagnostic markers. Additionally, these proteins might be aptly used for the generation of vaccines to improve current treatment options. Hence, a cDNA-based expression library was constructed and screened via microarrays to detect novel antigens of Klebsiella pneumoniae, a prominent agent of nosocomial infections well-known for its extensive antibiotics resistance, especially by extended-spectrum beta-lactamases (ESBL). After screening 1536 clones, 14 previously unknown immunogenic proteins were identified. Subsequently, each protein was expressed in full-length and its immunodominant character examined by ELISA and microarray analyses. Consequently, six proteins were selected for epitope mapping and three thereof possessed linear epitopes. After specificity analysis, homology survey and 3d structural modelling, one epitope sequence GAVVALSTTFA of KPN_00363, an ion channel protein, was identified harboring specificity for K. pneumoniae. The remaining epitopes showed ambiguous results regarding the specificity for K. pneumoniae. The approach adopted herein has been successfully utilized to discover novel antigens of Campylobacter jejuni and Salmonella enterica antigens before. Now, we have transferred this knowledge to the key nosocomial agent, K. pneumoniae. By identifying several novel antigens and their linear epitope sites, we have paved the way for crucial future research and applications including the design of point-of-care devices, vaccine development and serological screenings for a highly relevant nosocomial pathogen.

Vaccination with Klebsiella pneumoniae-derived extracellular vesicles protects against bacteria-induced lethality via both humoral and cellular immunity

“… 26 Various outer membrane proteins can be used as the candidate antigens for vaccine. 27 , 28 , 29 In the present study, we evaluated whether K. pneumoniae -derived EVs elicit a protective effect against Klebsiella infections. This study showed that vaccination with K. pneumoniae -derived EVs effectively protected bacteria-induced lethality in a murine sepsis model.…”

Cell Wall Anchoring of the Campylobacter Antigens to Lactococcus lactis

“…Thus, the market needs an effective anti- Campylobacter chicken vaccine. Recent progress has been made to understand the complex Campylobacter biology during chick colonization, as well as improvements in the technologies used for identifying the immunodominant proteins ( Hermans et al, 2011a ; Hoppe et al, 2014 ; Hu et al, 2014 ); both of these facilitate the selection of antigens for immunization.…”

Epitope determination of immunogenic proteins of Neisseria gonorrhoeae

“…Epitopes might be utilised for the generation of specific antibodies or for vaccination [ 15 ]. By identifying linear epitopes potential vaccine candidates have already been obtained for Staphylococcus aureus [ 16 ], Klebsiella pneunomiae [ 17 ] or the dengue virus [ 18 ] amongst others. Since the proteins were presented as polypeptide fragments on the phage surface and not as full-length proteins, only the former were analysed, thus significantly reducing the number of overlapping peptides needed for epitope mapping.…”