Identification and cloning of highly epitopic regions of Clostridium novyi alpha toxin

Authors: NAJME GORD NOSHAHRI, MOHSEN FATHI NAJAFI, ALI MAKHDOUMI KAKHKI, BEHJAT MAJIDI, MOHSEN MEHRVARZ

Abstract: The aim of the present study is to provide a strategy for predicting the production of antigenic regions of Clostridium novyi alpha toxin. The selection is based on B-cell epitopes and MHCII binding protein by immunoinformatics tools. The study resulted in identifying antigenic regions in the beginning and middle (3-17 and 965-997 amino acid residues) as suitable binders to MHCII and the carboxyl terminal of the protein (1800-1958 amino acid residues) in B-cell epitopes. The appropriate region in B-cell epitopes was chosen for cloning. The presence of recombinant protein was detected with immunological methods. Subsequently, BALB/C mice were immunized with the recombinant protein and alpha toxin, and the antibodies produced were evaluated by dot-blot and ELISA tests. After cloning the highly antigenic region (1799-1966 amino acid residues), the results of immunological tests showed that the recombinant protein reacts with antitoxin antibodies. Antirecombinant protein has a higher affinity to the alpha toxin than antialpha toxin. Thus, the carboxyl terminal of the protein (1799-1966 amino acid residues) in B-cell epitopes could be a proper candidate for a peptide vaccine against alpha toxin.

Keywords: Alpha toxin, Clostridium novyi, antigenic regions, conformational epitope, homology modeling

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