Es werden fadenförmige Strukturen beschrieben, die aus gereinigtem Newcastle Disease- und Mumps-Virus durch Schütteln mit Äther gewonnen werden konnten. Vermutlich handelt es sich und die g-Antigene dieser Viren.
Beim Virus der klassischen Geflügelpest läßt sich nach Reihenpassagen mit hohen Virusdosen im embryonierten Hühnerei und in der Gewebekultur ein v. Magnus - Phänomen erzeugen. Die in der Allantois des Hühnerembryos gebildeten Teilchen gleichen auch in ihren physikalischen Eigenschaften den „Inkompletten Formen“ der Influenza-Viren des Menschen.
With the aid of isotopic techniques the ribonucleic acid (RNA) and protein metabolism of embryonic chicken cells infected with fowl plague virus was studied. In addition to normal cell-RNA only viral RNA was found in the infected cells. The synthesis starts after 1 hour p.i. and proceeds during the rest of the infectious cycle. By labelling the viral subunits (s-antigen and hemagglutinin) with 14C-leucine it could be demonstrated, that the synthesis of their protein components starts also at about 1 hour post infectionem.
p-Fluorophenylalanine (FPA) had no influence on the normal RNA and protein metabolism of the cells. If FPA was given immediately after infection, no virus RNA was synthesized. FPA given 2 hours p.i. did not interfere anymore with the production of viral RNA. This was taken as evidence for the existence of an “early protein” necessary for the induction of virus multiplication, s-antigen grown in the presence of FPA and demonstrable by serological methods was not incorporated into the intact virus particle.
The findings suggest, that the synthesis of an “early protein” is necessary prior to viral RNA synthesis, that the RNA and the protein of the s-antigen are made simultaneously at the same site, and that the s-antigen acts as a template for the synthesis of the hemagglutinin-protein.
By a newly developed enzymatical characterization method for ribonucleic acid (RNA) a virus specific RNA can be detected with certainty not earlier than two hours after infection of monolayer tissue cultures of embryonic chicken cells by fowl plague virus. Almost all of this RNA is bound to the soluble antigen. After removal of the s-antigen the remaining cell-RNA, which is newly synthesized during the first three hours after infection, does not differ significantly from that of the non-infected cells.
Ebenso wie beim Poliomyelitis-Virus wird auch beim Influenza-Virus durch längere Einwirkung von HNO2 die antigene Struktur zerstört, außerdem leiden hier noch die hämagglutinierende Komponente und die Virus-Neuraminidase Schaden. Trotzdem lassen sich mit Hilfe dieser Inaktivierungsmethode sowohl beim Influenza-Virus wie auch bei einem weiteren Vertreter der Myxogruppe, dem Newcastle-Disease-Virus, brauchbare Vakzinen gewinnen, wenn man unter den eingehaltenen Bedingungen HNO2 beim Influenza-Virus 3 Stdn., beim NDV 1 Stde. einwirken läßt.
Actinomycin D (5 γ/ml) inhibits the synthesis of fowl plague virus RNA, S-antigen, hemagglutinin, neuraminidase and infectious particles. Even high concentrations (40 γ/ml) of the antibiotic do not inhibit the synthesis of the corresponding components of NDV. Although purified suspensions of these viruses can be inactivated by actinomycin in the presence of light, this photoeffect does not play an important role in the inhibition of fowl plague virus synthesis. If in the case of fowl plague virus actinomycin is added to tissue cultures at a time after infection when viral RNA synthesis has already started (1½—2 hours p. i.) further synthesis of viral RNA is stopped, while the S-antigen titer continues to rise.
Fowl plague (KP) virus and virus N have been examined in the electron microscope as both metal shadowed and negatively stained preparations. The particles of KP virus are very similar to those of influenza A. The products of ether splitting are (1) the G antigen, a ribonucleoprotein whose helically arranged protein subunits can be resolved and (2) the haemagglutinin, a star-shaped structure about 350 A diameter made up of the spikes which project from the surface of the intact particle. Incomplete forms have been prepared by serial undiluted passage, and these show great pleomorphism, but the same outer coat as complete virus. Ether splitting of incomplete forms yields a haemagglutinin like that from complete virus, but only traces of G antigen. Virus N is more pleomorphic than KP virus, but the products of ether splitting are very similar.
Bayer A 139, an ethylene-iminoquinone, reacts with nucleic acids at pH ≦ 7, leaving the protein intact. This compound inactivates fowl plaque virus, NDV, and TMV-RNA, following first order kinetics. In the case of fowl plaque virus it does not destroy the hemagglutinating, neuraminidase, interference, and antigenic activities. Intact TMV and ME-virus are not inactivated. With fowl plaque virus a phenomenon discussed as multiplicity reactivation was observed.