The frequency of early-activated hapten-specific B cell subsets predicts the efficacy of vaccines for nicotine dependence

• Published in: Vaccine Vol. 33; no. 46; pp. 6332 - 6339
• Main Authors: Laudenbach, M., Tucker, A.M., Runyon, S.P., Carroll, F.I., Pravetoni, M.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 17.11.2015; Elsevier Limited
• Subjects: Addiction; adjuvants; Adjuvants, Immunologic - metabolism; Allergy and Immunology; alum; Animals; antibodies; Antibodies - blood; Antigen-specific B cells; Antigens; B-Lymphocyte Subsets - immunology; Biomarkers; blood serum; brain; Brain research; Dependence; Drug Carriers - metabolism; Drug use; Flow Cytometry; haptens; Haptens - immunology; Hemocyanins - metabolism; illicit drugs; Immunization; Immunoglobulins; Immunology; Immunotherapy - methods; keyhole limpet hemocyanin; Laboratory animals; Lithium; Lymphocytes; Male; mice; Mice, Inbred BALB C; Mortality; Nicotine; Studies; T cell receptors; Tobacco; Tobacco Use Disorder - therapy; vaccine development; Vaccines; Biomarkers; Antigen-specific B cells; Vaccines; Addiction; Nicotine
• ISSN: 0264-410X; 1873-2518; 1873-2518
• DOI: 10.1016/j.vaccine.2015.09.015

•Two immunogens containing structurally-related nicotine haptens were compared in mice.•Hapten-specific B cells were analyzed by antigen-based magnetic enrichment and flow cytometry.•The most effective immunogen elicited more hapten-specific B cells shortly after immunization.•Early frequency of hapten-specific B cells correlated with vaccine efficacy against nicotine. Therapeutic vaccines for nicotine addiction show pre-clinical efficacy. Yet, clinical evaluation of the first-generation nicotine vaccines did not meet expectations because only a subset of immunized subjects achieved effective serum antibody levels. Recent studies suggest that vaccine design affects B cell activation, and that the frequency of the hapten-specific B cell subsets contributes to vaccine efficacy against drugs of abuse. To extend this hypothesis to nicotine immunogens, we synthesized a novel hapten containing a carboxymethylureido group at the 2-position of the nicotine structure (2CMUNic) and compared its efficacy to the previously characterized 6CMUNic hapten. Haptens were conjugated to the keyhole limpet hemocyanin (KLH) carrier protein, and evaluated for efficacy against nicotine in mice using the clinically approved alum adjuvant. Using a novel fluorescent antigen-based magnetic enrichment strategy paired with multicolor flow cytometry analysis, polyclonal hapten-specific B cell subsets were measured in mice immunized with either 6CMUNic-KLH or 2CMUNic-KLH. The 6CMUNic-KLH showed significantly greater efficacy than 2CMUNic-KLH on nicotine distribution to serum and to the brain. The 6CMUNic-KLH elicited higher anti-nicotine serum antibody titers, and greater expansion of hapten-specific B cells than 2CMUNic-KLH. Within the splenic polyclonal B cell population, a higher number of hapten-specific IgMhigh and germinal centre B cells predicted greater vaccine efficacy against nicotine distribution. These early pre-clinical findings suggest that hapten structure affects activation of B cells, and that variations in the frequency of early-activated hapten-specific B cell subsets underlie individual differences in vaccine efficacy.