Comparative Proteom Analysis of pathogenic and non-pathogenic Neisseria Species for the Identification of Immuno-Reactive Antigens

BACKGROUND AND OBJECTIVESNeisseria meningitidis is one of the major causative agents of bacterial meningitis in humans, especially among young children with high morbidity and mortality rates worldwide. Any delays in diagnosis and treatment of meningococcal disease can decrease the chance of survival. Unfortunately, there is still no universal vaccine against serogroup B strains. Antigenic similarities between N. lactamica as commensal species and N. meningitidis serogroup B (NmB) have been considered to develop an effective vaccine based on their common proteins to prevent life-threatening bacterial meningitis.MATERIALS AND METHODSThe whole proteome profiles of N. lactamica strains and a reference strain of the NmB were compared. Lysates from bacterial strains were resolved by two-dimensional gel electrophoresis (۲- ED), followed by Coommassie Brilliant Blue staining. Some of the matched protein spots were excised from the gel and subjected to matrix-assisted laser desorption/ionization-tandem time-of- flight mass spectrometry (MALDI-TOF/TOF MS) analysis. In the present study, aiming to find a set of common antigenic proteins between NmB and N. lactamica strains, ۲-DE-immunoblot of any studied bacterial strains was probed with sera from immunized mice corresponds to the same bacterial strains.RESULTS AND DISCUSSIONThe analysis of Coomassie-stained gels using ImageMaster ۲D Platinum software identified approximately ۸۰۰ protein spots. In addition, the results of ۲-DE gels showed that N. lactamica strains have approximately a proteome profile similar to each other and slightly different from NmB. MALDI-TOF/TOF MS identified ۴۷ common proteins between two species including membrane and cytoplasmic proteins. Using ۲-DE-immunoblot analyses, seven protein spots were identified as common immuno-reactive proteins between the two studied species. Some of them such as outer membrane protein P۱, competence lipoprotein, Thioredoxin reductase, and enoyl-ACP reductase are novel and can be recommended as novel vaccine candidates.CONCLUSIONThese results underscore the usefulness of proteome and immunoproteome analysis in successful identification of the common proteins and common immune-reactive proteins between N. lactamica strains and NmB as well. Further investigations are warranted to the possible applications of the present data in recommendation of the novel identified immune-reactive proteins as vaccine candidates against NmB.

کلیدواژه ها:

Neisseria meningitidis serogroup B ، Neisseria lactamica ، Two-dimensional gel electrophoresis ، Mass Spectrometry ، children