A study of the physiology of Bacillus anthracis Sterne during manufacture of the UK acellular anthrax vaccine

Abstract

Aim: To analyse the growth of Bacillus anthracis during simulations of the UK anthrax vaccine manufacturing process. Methods and Results: Simulated vaccine production runs were performed using the toxigenic, acapsulate Sterne 34F2 strain of B. anthracis in semi‐defined medium. After rising during the logarithmic growth phase, the pH of the culture starts to fall at about 18 h from pH 8·7 to reach <7·6 at 26 h, coincident with consumption of glucose and optimal production of protective antigen (PA; 7·89 g ml−1, SD 1·0) and lethal factor (LF; 1·85 g ml−1, SD 0·29). No increased breakdown of toxin antigens was seen over the 26–32 h period. When glucose was exhausted, amino acids (principally serine) were utilized as an alternative carbon source. Sporulation was not observed during the 32 h. Conclusions: PA and LF, the principal constituents in the UK anthrax vaccine, undergo little degradation during vaccine fermentation. The vaccine manufacturing process is robust and reproducible. Significance and Impact of the Study: This is the first detailed analysis of the manufacturing process used for the UK acellular anthrax vaccine; insight gained into the process will support continued and safe vaccine manufacture.

Anthrax Vaccine Precipitated Induces Edema Toxin-Neutralizing, Edema Factor-Specific Antibodies in Human Recipients

“…Serum samples from AVP recipients (n ϭ 33), matched 1:2 with plasma samples from AVA recipients (n ϭ 66) for number of vaccinations, time postvaccination, and age, where known (Table 1), were tested by enzyme-linked immunosorbent assay (ELISA) for antibodies directed against EF and PA. Samples from AVP recipients (26/33; 78.8%) were significantly more likely than those from matched AVA recipients (2/66; 3.1%) to contain EF IgG at an end titer of Ն100 (P Ͻ 0.0001; odds ratio [OR], 118.9), which is to be expected, since the AVP vaccine contains EF (26,39). In addition, the average EF IgG titer also differed between the AVP (244.3 Ϯ 63.3) and AVA (6.6 Ϯ 2.1) groups (P Ͻ 0.0001) (Fig.…”

“…In the present study, we sought to determine the contribution of human EF-specific antibodies to ET neutralization. We sought to study these antibodies by examining serum samples from recipients of the AVP vaccine, which contains detectable EF (26). EF-specific IgG at titers of Ն100 was observed in 79% of the AVP recipient samples compared to 4% in the AVA group; however, there was no statistical difference in ET neutralization between the two groups.…”

“…Vaccination consists of five intramuscular injections at 0, 1, 6, 12, and 18 months, followed by annual boosters (25). The AVP vaccine is composed of a cell-free filtrate of the acapsular, toxigenic B. anthracis Sterne 34F2 strain that is precipitated with aluminum potassium sulfate (Alum) (26). Unlike the AVA vaccine, AVP contains all three toxin components, with roughly 7.9 g/ml PA, 1.9 g/ml LF, and detectable amounts of EF (26).…”

“…Two human anthrax vaccines are currently given in the western world, anthrax vaccine adsorbed (AVA) and anthrax vaccine precipitated (AVP) (24)(25)(26). AVA is the only anthrax vaccine currently approved for use in the United States, while AVP is licensed in the United Kingdom.…”

“…The AVP vaccine is composed of a cell-free filtrate of the acapsular, toxigenic B. anthracis Sterne 34F2 strain that is precipitated with aluminum potassium sulfate (Alum) (26). Unlike the AVA vaccine, AVP contains all three toxin components, with roughly 7.9 g/ml PA, 1.9 g/ml LF, and detectable amounts of EF (26). Vaccination with AVP consists of 4 intramuscular doses, administered at 0, 3, 6, and 32 weeks, with annual boosters (28).…”