biostudies-literatureUnknown12(12)Rudenko NCSRD VA<i>Bacillus cereus</i> is the fourth most common cause of foodborne illnesses that produces a variety of pore-forming proteins as the main pathogenic factors. <i>B. cereus</i> hemolysin II (HlyII), belonging to pore-forming ?-barrel toxins, has a C-terminal extension of 94 amino acid residues designated as HlyIICTD. An analysis of a panel of monoclonal antibodies to the recombinant HlyIICTD protein revealed the ability of the antibody HlyIIC-20 to inhibit HlyII hemolysis. A conformational epitope recognized by HlyIIC-20 was found. by the method of peptide phage display and found that it is localized in the N-terminal part of HlyIICTD. The HlyIIC-20 interacted with a monomeric form of HlyII, thus suppressing maturation of the HlyII toxin. Protection efficiencies of various <i>B. cereus</i> strains against HlyII were different and depended on the epitope amino acid composition, as well as, insignificantly, on downstream amino acids. Substitution of L324P and P324L in the hemolysins ATCC14579^T and B771, respectively, determined the role of leucine localized to the epitope in suppressing the hemolysis by the antibody. Pre-incubation of HlyIIC-20 with HlyII prevented the death of mice up to an equimolar ratio. A strategy of detecting and neutralizing the toxic activity of HlyII could provide a tool for monitoring and reducing <i>B. cereus</i> pathogenicity.Toxinshttps://www.ebi.ac.uk/biostudies/studies/S-EPMC7767301biostudies-literatureA Monoclonal Antibody against the C-Terminal Domain of <i>Bacillus cereus</i> Hemolysin II Inhibits HlyII Cytolytic Activity.PMC77673011Rudenko NZamyatina AMelnik BSolonin AKolesnikov ASalyamov VSiunov AKaratovskaya ABrovko FAndreeva-Kovalevskaya ZShepelyakovskaya ANagel ABoziev KfalseA Monoclonal Antibody against the C-Terminal Domain of <i>Bacillus cereus</i> Hemolysin II Inhibits HlyII Cytolytic Activity.<i>Bacillus cereus</i> is the fourth most common cause of foodborne illnesses that produces a variety of pore-forming proteins as the main pathogenic factors. <i>B. cereus</i> hemolysin II (HlyII), belonging to pore-forming ?-barrel toxins, has a C-terminal extension of 94 amino acid residues designated as HlyIICTD. An analysis of a panel of monoclonal antibodies to the recombinant HlyIICTD protein revealed the ability of the antibody HlyIIC-20 to inhibit HlyII hemolysis. A conformational epitope recognized by HlyIIC-20 was found. by the method of peptide phage display and found that it is localized in the N-terminal part of HlyIICTD. The HlyIIC-20 interacted with a monomeric form of HlyII, thus suppressing maturation of the HlyII toxin. Protection efficiencies of various <i>B. cereus</i> strains against HlyII were different and depended on the epitope amino acid composition, as well as, insignificantly, on downstream amino acids. Substitution of L324P and P324L in the hemolysins ATCC14579^T and B771, respectively, determined the role of leucine localized to the epitope in suppressing the hemolysis by the antibody. Pre-incubation of HlyIIC-20 with HlyII prevented the death of mice up to an equimolar ratio. A strategy of detecting and neutralizing the toxic activity of HlyII could provide a tool for monitoring and reducing <i>B. cereus</i> pathogenicity.2020-01-01T00:00:00Z2020 Dec2021-02-20T17:25:56Z2021-02-20T17:25:56ZS-EPMC77673013335274410.3390/toxins12120806