The use of highly concentrated purified (by a large scale method) and long term liquid nitrogen stored foot-and-mouth disease viruses for the preparation of vaccines: physico-chemical quality controls and potency tests after storage.

In 1974 a new industrial technique for concentration and purification of FMD virus was presented at the OIE Conference. The bulk inactivated virus from this technique was stored in liquid nitrogen vapour until required for vaccine formulation. In 1981, having applied this technique regularly for seven years, we now describe the results obtained and the advantages gained in the field of trivalent O, A, C bovine vaccine production. Vaccines prepared from such bulk virus stocks after several years storage give good protection against virulent virus challenge.

[Routine physico-chemical testing of concentrated virulent and inactivated foot-and-mouth disease virus antigens]. / Contrôles physico-chimiques de routine d'antigènes aphteux concentrés virulents et inactivés.

The ponderal quantity of 140 S antigens and their peptide distribution are controlled in concentrated virulent and inactivated preparations proir to their being transformed into vaccines. A certain variability in the amount of 140 S particles and in the titer of peptide sensitive to trypsin (VP1) has been demonstrated in the virulent preparations. After treatment by inactivating agents (glycidaldehyde, binary ethyleneimine and formaldehyde) two types of alteration of the viral capsid are shown : one leads to the partial cleavage of VP1 (glycidaldehyde and binary ethyleneimine), the other leads to the detaching of an important quantity of VP1 from the capsid (formaldehyde). The degradation by formadehyde of the 140 S particles of type O and type C into 12 S particles is underlined, as well as the relatuve stability of type A and the relatuve lability of type C. The results are discussed in terms of immunogenicity.