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Infect Immun. 2018 May 22;86(6). pii: e00004-18. doi: 10.1128/IAI.00004-18. Print 2018 Jun.

Characterization of Individual Human Antibodies That Bind Pertussis Toxin Stimulated by Acellular Immunization.

Author information

1
Department of Biochemistry, The University of Texas at Austin, Austin, Texas, USA.
2
Excelimmune, Inc., Woburn, Massachusetts, USA.
3
McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas, USA.
4
Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan, USA.
5
Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, Michigan, USA.
6
Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, Michigan, USA.
7
Department of Biochemistry, The University of Texas at Austin, Austin, Texas, USA maynard@che.utexas.edu.

Abstract

Despite high vaccination rates, the incidence of whooping cough has steadily been increasing in developing countries for several decades. The current acellular pertussis (aP) vaccines all include the major protective antigen pertussis toxin (PTx) and are safer, but they appear to be less protective than infection or older, whole-cell vaccines. To better understand the attributes of individual antibodies stimulated by aP, we isolated plasmablast clones recognizing PTx after booster immunization of two donors. Five unique antibody sequences recognizing native PTx were recovered and expressed as recombinant human IgG1 antibodies. The antibodies all bind different epitopes on the PTx S1 subunit, B oligomer, or S1-B subunit interface, and just one clone neutralized PTx in an in vitro assay. To better understand the epitopes bound by the nonneutralizing S1-subunit antibodies, comprehensive mutagenesis with yeast display provided a detailed map of the epitope recognized by antibodies A8 and E12. Residue R76 is required for antibody A8 binding and is present on the S1 surface but is only partially exposed in the holotoxin, providing a structural explanation for A8's inability to neutralize holotoxin. The B-subunit-specific antibody D8 inhibited PTx binding to a model receptor and neutralized PTx in vitro as well as in an in vivo leukocytosis assay. This is the first study, to our knowledge, to identify individual human antibodies stimulated by the acellular pertussis vaccine and demonstrates the feasibility of using these approaches to address outstanding issues in pertussis vaccinology, including mechanisms of accelerated waning of protective immunity despite repeated aP immunization.

KEYWORDS:

B cells; Bordetella; Bordetella pertussis; antibodies; epitope; neutralizing antibody; pertussis toxin; plasmablast; whooping cough

PMID:
29581192
PMCID:
PMC5964521
DOI:
10.1128/IAI.00004-18
[Indexed for MEDLINE]
Free PMC Article

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