[Suppression of the proteolytic activation of myxoviruses in infected chick embryos by using aprotinin].
The mandatory step in reproduction of myxoviruses (influenza viruses and paramyxoviruses) is proteolytic shearing of viral glycoproteins activating the infectivity of virions. Such activation of myxoviruses is realized by trypsin-like proteases of the host. This study demonstrated that proteolytic activation of virions could be inhibited by a physiological inhibitor of proteases, aprotinine. A single injection of aprotinine (preparations Gordox or Contrycal) into chick embryos infected with various influenza viruses (WSN/34, Udorn/72) and paramyxoviruses (Sendai/960, NDV/La Sota, NDV/Queensland) blocked shearing of viral glycoproteins, HA, FO, HNO as a result of which noninfectious virions with unsheared glycoproteins were predominantly synthesized. In aprotinine-treated embryos, multicycle virus infection was markedly decreased which led to the 10(4)-fold or greater reduction of the virus yield. The antiviral effect of protease inhibitors and possibilities of their practical use in viral diseases are discussed.