Abstract: Anthrax Vaccine Adsorbed (AVA) generates short-lived protective antigen (PA) specific IgG that correlates with in vitro toxin neutralization and protection from Bacillus anthracis challenge. Animal studies suggest that when PA-specific IgG has waned, survival after spore challenge correlates with an activation of PA-specific memory B cells. Here, we characterize the quantity and the longevity of AVA-induced memory B cell responses in humans. Peripheral blood mononuclear cells (PBMCs) from individuals vaccinated ≥3 times with AVA (n = 50) were collected early (3–6 months, n = 27) or late after their last vaccination (2–5 years, n = 23), pan-stimulated, and assayed by ELISPOT for total and PA-specific memory B cells differentiated into antibody secreting cells (ASCs). PA-specific ASC percentages ranged from 0.02% to 6.25% (median: 1.57%) and did not differ between early and late post-vaccination individuals. PA-specific ASC percentages correlated with plasma PA-specific IgG (r = 0.42, p = 0.03) and toxin neutralization (r = 0.52, p = 0.003) early post vaccination. PA-specific ASC percentages correlated with supernatant anti-PA both early (r = 0.60, p = 0.001) and late post vaccination (r = 0.71, p < 0.0001). These data suggest PA-specific memory B cell responses are long-lived and can be estimated after recent vaccination by the magnitude and neutralization capacity of the humoral response.
This is an open access article distributed under the
Creative Commons Attribution License which permits unrestricted use, distribution,
and reproduction in any medium, provided the original work is properly cited.
Export to BibTeX
MDPI and ACS Style
Garman, L.; Smith, K.; Farris, A.D.; Nelson, M.R.; Engler, R.J.M.; James, J.A. Protective Antigen-Specific Memory B Cells Persist Years after Anthrax Vaccination and Correlate with Humoral Immunity. Toxins 2014, 6, 2424-2431.
Garman L, Smith K, Farris AD, Nelson MR, Engler RJM, James JA. Protective Antigen-Specific Memory B Cells Persist Years after Anthrax Vaccination and Correlate with Humoral Immunity. Toxins. 2014; 6(8):2424-2431.
Garman, Lori; Smith, Kenneth; Farris, A. D.; Nelson, Michael R.; Engler, Renata J.M.; James, Judith A. 2014. "Protective Antigen-Specific Memory B Cells Persist Years after Anthrax Vaccination and Correlate with Humoral Immunity." Toxins 6, no. 8: 2424-2431.