Memory B Cells Encode Neutralizing Antibody Specific for Toxin B from the Clostridium difficile Strains VPI 10463 and NAP1/BI/027 but with Superior Neutralization of VPI 10463 Toxin B.
Secreted toxin B (TcdB) substantially contributes to the pathology observed during Clostridium difficile infection. To be successfully incorporated into a vaccine, TcdB-based immunogens must stimulate the production of neutralizing antibody (Ab)-encoding memory B cells (Bmem cells). Despite numerous investigations, a clear analysis of Bmem cellular responses following vaccination against TcdB is lacking. B6 mice were therefore used to test the ability of a nontoxigenic C-terminal domain (CTD) fragment of TcdB to induce Bmem cells that encode TcdB-neutralizing antibody. CTD was produced from the historical VPI 10463 strain (CTD1) and from the hypervirulent strain NAP1/BI/027 (CTD2). It was then demonstrated that CTD1 induced strong recall IgG antibody titers, and this led to the development of functional Bmem cells that could be adoptively transferred to naive recipients. Bmem cell-driven neutralizing Ab responses conferred protection against lethal challenge with TcdB1. Further experiments revealed that an experimental adjuvant (Imject) and a clinical adjuvant (Alhydrogel) were compatible with Bmem cell induction. Reactivity of human Bmem cells to CTD1 was also evident in human peripheral blood mononuclear cells (PBMCs), suggesting that CTD1 could be a good vaccine immunogen. However, CTD2 induced strong Bmem cell-driven antibody titers, and the CTD2 antibody was neutralizing in vitro, but its protection against lethal challenge with TcdB2 was limited to delaying time to death. Therefore, CTD from different C. difficile strains may be a good immunogen for stimulating B cell memory that encodes in vitro neutralizing Ab but may be limited by variable protection against intoxication in vivo.
Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.
T Scott
TS
Devera
Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.
Gillian A
GA
Lang
Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.
Jordi M
JM
Lanis
Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.
Pragya
P
Rampuria
Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.
Casey L
CL
Gilmore
Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA Oklahoma Clinical and Translational Science Institute, Oklahoma City, Oklahoma, USA.
Judith A
JA
James
Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.
Jimmy D
JD
Ballard
Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA mark-lang@ouhsc.edu.
Mark L
ML
Lang
D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology; D057134:Antibodies, Neutralizing / Q000276:immunology*; D000992:Antitoxins / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology*; D001427:Bacterial Toxins / Q000276:immunology*; D016466:CHO Cells; D002460:Cell Line; D016360:Clostridioides difficile / Q000276:immunology* / Q000472:pathogenicity; D003015:Clostridium Infections / Q000276:immunology / Q000473:pathology; D003412:Cricetulus; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D007156:Immunologic Memory / Q000276:immunology; D007963:Leukocytes, Mononuclear / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D017434:Protein Structure, Tertiary
D000907:Antibodies, Bacterial; D057134:Antibodies, Neutralizing; D000992:Antitoxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D007074:Immunoglobulin G; C031815:toxB protein, Clostridium difficile