Frühstadium der Immunität nach Impfung von Ferkeln mit einer inaktivierten Aujeszkyvirus‐Vakzine

Abstract

Zusammenfassung Nach Impfung von 6–8 Wochen alten Ferkeln mit einer Aujeszkyvirus (AV)‐Vakzine, die aus Äthylenimin‐inaktivertem Virus und DEAE‐Dextran als Adjuvans bestand, konnten neutralisierende Antikörper zum ersten Mal eine Woche nach der Impfung nachgewiesen werden. Während des geprüften Zeitraumes (6 Wochen) waren die Titer relativ nieder und die Mittelwerte zeigten keinen signifikanten Anstieg oder Abfall. Im Gegensatz zur Antikörperbildung traten bei den vakzinierten Tieren nach intranasaler Testinfektion zeitlich bedingte Immunitätsunterschiede auf. Während die vakzinierten Tiere eine Woche und 2 Wochen post vacc. immun waren, konnte 3 Wochen post vacc. ein gewisses Nachlassen des Impfschutzes festgestellt werden. Dagegen war der Impfschutz 6 Wochen post vacc. wieder stark ausgeprägt. Letzteres dürfte damit im Zusammenhang stehen, daß nach dem Verhalten der infizierten nicht vakzinierten Kontrolltiere zu schließen, die natürliche Resistenz von Ferkeln gegen das AV mit zunehmendem Alter rasch ansteigt. Die Ergebnisse wurden im Hinblick auf die Impfprophylaxe gegen AV besprochen. Summary Early stages of immunity after vaccination of piglets with an inactivated Aujeszky virus vaccine Vaccination of 6–8 week old piglets with an Aujeszky virus (AV) vaccine, consisting of ethyleneimine‐inactivated virus and DEAE dextran as adjuvant, resulted in detectable neutralizing antibody levels one week later. The titres were rather low and the mean values showed no significant rise or decline during the test period (6 weeks). Contrary to antibody production the vaccinated animals showed differences in protection against intranasal challange infection depending on vaccination time elapsed. One week and 2 weeks post vacc. the vaccinated animals were immune, whereas 3 weeks post vacc. a partial reduction of protection could be found. However, protection was very good again after 6 weeks post vacc. This may be connected with the finding that natural resistance of pigs against AV rises with age, as was shown by the infection of non vaccinated control pigs. The results are discussed with regard to immune prophylaxis against AV. Résumé Stades précoces de l'immunité après une vaccination de porcelets avec un vaccin inactivé du virus de la maladie d'Aujeszky Des anticorps neutralisants sont apparus une semaine après la vaccination de porcelets âgés de 6–8 semaines avec un vaccin du virus de la maladie d'Aujeszky (AV) inactive par l'éthyleninine et avec DEAE‐dextran comme adjuvant. Les titres furent relativement bas durant le temps d'examination (6 semaines) et les valeurs moyennes ne présentèrent aucune élévation ou chute spécifique. Certaines différences d'immunité sont intervenues dans la formation d'anticorps chez des animaux vaccinés après une infection intranasale expérimentale. Alors que les animaux vaccinés étaient immunisés une et deux semaines après la vaccination, on a constaté une certaine faiblesse de la protection vaccinale après trois semaines. La protection fut à nouveau renforcée six semaines après la vaccinati...

Neutralizing Antibody Titres in Pig Serum after Revaccination with an Inactivated Aujeszky Disease Virus (ADV) Vaccine

“…In a previous publication we described that in 6 to 8 week old pigs a partial reduction of protection against challenge infection had been noticed 3 weeks after the application of a vaccine, consisting of ethylene-inactivated ADV and DEAE dextran as an adjuvant (WITTMANN and JAKUBIK, 1977). In spite of the fact that the clinical reactions in the control animals were significantly severer, we concluded from those experiments that a single vaccine dose not evoke optimal immunity and therefore a second vaccination should be recommended.…”

“…From these results one can conclude that the optimal time for revaccination would be 3 or 4 weeks post vacc. ; however, in a previous investigation we found that after a single vaccination the protection of the pigs against challenge infection had declined after 3 weeks (WITTMANN and JAKUBIK, 1977). Therefore, it is advisable to revaccinate 2 weeks post vacc.…”

“…The virus was inactivated by 0.1 5 O / o ethyleneimine (Schuchard, Miinchen) and DEAE dcxtraii MW 5 x 105 (Pharmacia, Uppsala, Sweden) was added to give a final concentration of 0.5 g. per vaccine dose (5 ml.). Details of vaccine preparation and iniiocuity testing have been given (WITTMANN and JAKUBIK, 1977).…”

“…The neutralizing antibody titres in the sera were determined as a measure of the immune response. Unfortunately, the immune state of the vaccinated animals could not be tested by challenge infection because of the irregular behaviour of older pigs against challenge (WITTMANN and JAKUBIK, 1977), and since we had only a limited number of pigs available. In the present paper we describe the humoral immune response and the influence on this response related to the interval between the first and the second vaccination.…”

Effects of physical and chemical factors on pseudorabies virus activity in vitro

“…Therefore, swine are de ned as the natural host of PRV. The nasal mucosa and oral cavity are the main sites of infection, and oral administration is more e cient than nasal inoculation [12]. PRV can also infect through vaginal mucosa or semen, which is the main mode of PRV transmission in wild boar herds.…”