S Dupke1, A Barduhn1, T Franz1, F H Leendertz2, E Couacy-Hymann3, R Grunow1, S R Klee1. 1. Robert Koch-Institute, Centre for Biological Threats and Special Pathogens (ZBS2), Berlin, Germany. 2. Robert Koch-Institute, Epidemiology of Highly Pathogenic Microorganisms (P3), Berlin, Germany. 3. Laboratoire National d'Appui au Développement Agricole (LANADA), Laboratoire Central Vétérinaire de Bingerville (LCVB), Bingerville, Côte d'Ivoire.
Abstract
AIMS: The aim of this work was to identify a protein which can be used for specific detection of antibodies against Bacillus cereus biovar anthracis (Bcbva), an anthrax-causing pathogen that so far has been described in African rainforest areas. METHODS AND RESULTS: Culture supernatants of Bcbva and classic Bacillus anthracis (Ba) were analysed by gel electrophoresis, and a 35-kDa protein secreted only by Bcbva and not Ba was detected. The protein was identified as pXO2-60 by mass spectrometry. Sequence analysis showed that Ba is unable to secrete this protein due to a premature stop codon in the sequence for the signal peptide. Immunization of five outbred mice with sterile bacterial culture supernatants of Bcbva revealed an immune response in ELISA against pXO2-60 (three mice positive, one borderline) and the protective antigen (PA; four mice). When supernatants of classic Ba were injected into mice or human sera from anthrax patients were analysed, only antibodies against PA were detected. CONCLUSIONS: In combination with PA, the pXO2-60 protein can be used for the detection of antibodies specific against Bcbva and discriminating from Ba. SIGNIFICANCE AND IMPACT OF THE STUDY: After further validation, serological assays based on pXO2-60 can be used to perform seroprevalence studies to determine the epidemiology of B. cereus bv anthracis in affected countries and assess its impact on the human population.
AIMS: The aim of this work was to identify a protein which can be used for specific detection of antibodies against Bacillus cereus biovar anthracis (Bcbva), an anthrax-causing pathogen that so far has been described in African rainforest areas. METHODS AND RESULTS: Culture supernatants of Bcbva and classic Bacillus anthracis (Ba) were analysed by gel electrophoresis, and a 35-kDa protein secreted only by Bcbva and not Ba was detected. The protein was identified as pXO2-60 by mass spectrometry. Sequence analysis showed that Ba is unable to secrete this protein due to a premature stop codon in the sequence for the signal peptide. Immunization of five outbred mice with sterile bacterial culture supernatants of Bcbva revealed an immune response in ELISA against pXO2-60 (three mice positive, one borderline) and the protective antigen (PA; four mice). When supernatants of classic Ba were injected into mice or human sera from anthraxpatients were analysed, only antibodies against PA were detected. CONCLUSIONS: In combination with PA, the pXO2-60 protein can be used for the detection of antibodies specific against Bcbva and discriminating from Ba. SIGNIFICANCE AND IMPACT OF THE STUDY: After further validation, serological assays based on pXO2-60 can be used to perform seroprevalence studies to determine the epidemiology of B. cereus bv anthracis in affected countries and assess its impact on the human population.
Authors: Daniel Romero-Alvarez; A Townsend Peterson; Johanna S Salzer; Claudia Pittiglio; Sean Shadomy; Rita Traxler; Antonio R Vieira; William A Bower; Henry Walke; Lindsay P Campbell Journal: PLoS Negl Trop Dis Date: 2020-03-09