Mechanism and process optimization of ultrafiltration of residual DNA in rabies vaccine / 军事医学

ABSTRACT

Objective To control residual DNA by optimizing methodology during the production of rabies vaccine using Vero cells as a vector .Methods The antigen recovery rate was assessed by linked immunosorbent assay-sandwich technique while the residual DNA was detected by DNA probe hybridization method .Antigen recovery and removal of DNA were the main indexes for evaluateing ultrafiltration , the vital part of rabies vaccine production .Three key factors in ultrafiltration were assessed selection of membrane packages , ultrafiltration pressure and the concentration ratio .Then protamine was used to pretreat ultrafiltrates .Based on the two indicators mentioned above , the effect of protamine pretreat-ment on the ultrafiltrate was evaluated .Results and Conclusion The optimum condition of ultrafiltration was obtained on the basis of the general antigen recovery rate , DNA removal rate and actual production .The primary parameters of ultrafil-tration were as follows7.5 ×105 ultrafiltration membrane packages, 20 times concentrated, 15 psi ultrafiltration pressure. After pretreatment with protamine , ultrafiltration has proved to be a molecular sieve in intercepting DNA ,while protamine can tangle the fragmented DNA and form a larger molecular segment , which is believed to be more conducive to ultrafiltra-tion interception .