[Seasonal variations in the formation of virus-neutralizing antibodies in cattle after vaccination against foot-and-mouth disease]. / Jahreszeitliche Schwankungen der Bildung virusneutralisierender Antikörper nach Impfung gegen Maul- und Klauenseuche beim Rind.

The GDR in 1977 had been the first country to introduce a laboratory method for potency testing of FMD vaccines on the basis of secured correlations between titres of virus-neutralising serum antibodies of immunised cattle, on the one hand, and their probit-transformed protection against FMD, on the other. This is now the only state-registered method for potency testing. The method has ever since worked well all over the place. An evaluation of results obtained between 1982 and 1988 revealed seasonal variations of anti-FMD immunogenesis in cattle. FMD immunisations from February to July proved more effective than those performed in the rest of the year, in that higher antibody titres were built up within 14 days from vaccination. These results were confirmed by rates of protection of cattle recorded from direct potency testing of immunised animals, between 1969 and 1977.

[Enzymatic protein hydrolysate as the N-source for cell culture]. / Enzymatische Eiweisshydrolysate als N-Quelle für Zellkulturen.

Supplement T, a preparation for cell culture growth, is just as effective as commercially available tryptose. It has met high demands throughout its application over six years under conditions of large-scale production of permanent cell lines. Supplement B has been used with good success in commercial production for breeding of FMD virus in BHC cells of IBR/IPN and PI-3 viruses in calf kidney cells cultures and of embryonic duck fibroblast cell cultures for production of vaccines against Marek's disease.