title: Detection of protective antigen, an anthrax specific toxin in human serum by using surface plasmon resonance.
abstract: In this study, surface plasmon resonance (SPR) technology was used for the sensitive detection of protective antigen (PA), an anthrax specific toxin in spiked human serum samples. A monoclonal antibody raised against Bacillus anthracis PA was immobilized on carboxymethyldextran-modified gold chip, and its interaction with PA was characterized in situ by SPR. By using kinetic evaluation software, KD (equilibrium constant) and Bmax (maximum binding capacity of analyte) were found to be 20 fM and 18.74 m°, respectively. The change in Gibb's free energy (∆G= -78.04 kJ/mol) confirmed the spontaneous interaction between antigen and antibody. The assay could detect 1 pg/mL purified PA. In PA-spiked human serum samples, 10 pg/mL of PA could be detected. Presence of PA in blood samples serves as an important early diagnostic marker for B. anthracis infections. Thus, SPR test can be a sensitive assay for detection of anthrax at early stages of infection.
authors.affiliation: Biotechnology Division, Defence Research & Development Establishment, Gwalior-474 002, India.
authors.forename: Neha
authors.initials: N
authors.lastname: Ghosh
authors.forename: Nidhi
authors.initials: N
authors.lastname: Gupta
authors.forename: Garima
authors.initials: G
authors.lastname: Gupta
authors.forename: Mannan
authors.initials: M
authors.lastname: Boopathi
authors.forename: Vijay
authors.initials: V
authors.lastname: Pal
authors.forename: Ajay Kumar
authors.initials: AK
authors.lastname: Goel
mesh_terms: D000881:Anthrax / Q000175:diagnosis*; D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial / Q000097:blood*; D000992:Antitoxins; D001427:Bacterial Toxins / Q000097:blood*; D019411:Clinical Laboratory Techniques / Q000379:methods*; D042241:Early Diagnosis; D006801:Humans; D012680:Sensitivity and Specificity; D044967:Serum / Q000737:chemistry*; D020349:Surface Plasmon Resonance / Q000379:methods*
chemical_list: D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D000992:Antitoxins; D001427:Bacterial Toxins; C030325:anthrax toxin
keywords: Anthrax; Bacillus anthracis; Monoclonal antibody; Protective antigen; Surface plasmon resonance