Patterns of Antibody Response in Humans to the Anthrax Vaccine Adsorbed (AVA) Primary (six-dose) Series

摘要

The antibody profile during and after the six-dose primary vaccination series with anthrax vaccine adsorbed (AVA, BiothraxTM)was characterized in 86 human volunteers. Ninety-three percent of recipients developed IgG antibodies to Bacillus anthracis protective antigen (PA) after two doses, and 100% were seropositive after dose No. 3. Geometric mean concentrations (GMC) of IgG to PA measured before and after each dose were significantly lower after injection No. 3 (peak GMC = 146.65 micrograms /mL, trough GMC = 15.16 micrograms/mL) than after injections No. 4 (peak GMC = 430.46micrograms/mL, trough GMC 96.19 micrograms/mL) (p < 0.0001 for each); but not between injections No. 4, No. 5 and No. 6, or No. 4 and No. 6 (p < 0.7923 for each). Decay rates for IgG to PA were significantly faster after infection No. 3 (half life T1/2) 39.21 days than after injections no. 4 (T1/2 = 70.14 days (p < 0.0282 for each)). Toxin neutralizing assay (TNA) antibody patterns generally paralled those for IgG to PA. The 6-month dose in the AVA primary series appears to be critical in sustaining IgG to PA concentrations in a substantial proportion of recipients.