title: Generation and Characterization of Human Monoclonal Antibodies Targeting Anthrax Protective Antigen following Vaccination with a Recombinant Protective Antigen Vaccine.
abstract: The anthrax protective antigen (PA) is the central component of the three-part anthrax toxin, and it is the primary immunogenic component in the approved AVA anthrax vaccine and the "next-generation" recombinant PA (rPA) anthrax vaccines. Animal models have indicated that PA-specific antibodies (AB) are sufficient to protect against infection with Bacillus anthracis. In this study, we investigated the PA domain specificity, affinity, mechanisms of neutralization, and synergistic effects of PA-specific antibodies from a single donor following vaccination with the rPA vaccine. Antibody-secreting cells were isolated 7 days after the donor received a boost vaccination, and 34 fully human monoclonal antibodies (hMAb) were identified. Clones 8H6, 4A3, and 22F1 were able to neutralize lethal toxin (LeTx) both in vitro and in vivo. Clone 8H6 neutralized LeTx by preventing furin cleavage of PA in a dose-dependent manner. Clone 4A3 enhanced degradation of nicked PA, thereby interfering with PA oligomerization. The mechanism of 22F1 is still unclear. A fourth clone, 2A6, that was protective only in vitro was found to be neutralizing in vivo in combination with a toxin-enhancing antibody, 8A7, which binds to domain 3 of PA and PA oligomers. These results provide novel insights into the antibody response elicited by the rPA vaccine and may be useful for PA-based vaccine and immunotherapeutic cocktail design.
authors: Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, China.
authors: Xiangyang
authors: X
authors: Chi
authors: Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, China.
authors: Jianmin
authors: J
authors: Li
authors: Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, China.
authors: Weicen
authors: W
authors: Liu
authors: Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, China.
authors: Xiaolin
authors: X
authors: Wang
authors: Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, China.
authors: Kexin
authors: K
authors: Yin
authors: Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, China.
authors: Ju
authors: J
authors: Liu
authors: Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, China.
authors: Xiaodong
authors: X
authors: Zai
authors: Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, China.
authors: Liangliang
authors: L
authors: Li
authors: Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, China.
authors: Xiaohong
authors: X
authors: Song
authors: Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, China.
authors: Jun
authors: J
authors: Zhang
authors: Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, China.
authors: Xiaopeng
authors: X
authors: Zhang
authors: Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, China.
authors: Ying
authors: Y
authors: Yin
authors: Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, China.
authors: Ling
authors: L
authors: Fu
authors: Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, China.
authors: Junjie
authors: J
authors: Xu
authors: Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, China yuchangming@126.com cw0226@foxmail.com.
authors: Changming
authors: C
authors: Yu
authors: Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, China yuchangming@126.com cw0226@foxmail.com.
authors: Wei
authors: W
authors: Chen
mesh_terms: D000328:Adult; D022122:Anthrax Vaccines / Q000008:administration & dosage / Q000276:immunology*; D000907:Antibodies, Bacterial / Q000097:blood / Q000276:immunology*; D000911:Antibodies, Monoclonal / Q000276:immunology* / Q000302:isolation & purification*; D057134:Antibodies, Neutralizing / Q000276:immunology / Q000302:isolation & purification*; D000918:Antibody Specificity; D000921:Antibody-Producing Cells / Q000276:immunology; D000942:Antigens, Bacterial / Q000276:immunology* / Q000378:metabolism; D001427:Bacterial Toxins / Q000276:immunology* / Q000378:metabolism; D018985:Epitopes, B-Lymphocyte / Q000276:immunology; D045683:Furin / Q000378:metabolism; D006801:Humans; D007117:Immunization, Secondary; D008297:Male; D009500:Neutralization Tests; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000276:immunology
chemical_list: D022122:Anthrax Vaccines; D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D057134:Antibodies, Neutralizing; D000942:Antigens, Bacterial; D001427:Bacterial Toxins; D018985:Epitopes, B-Lymphocyte; D014614:Vaccines, Synthetic; C030325:anthrax toxin; D045683:Furin