Cell phenomena in experimental viral-bacterial infections in mice. I. The release of leukocyte inhibiting factor (LIF) from mouse spleen leukocytes in the presence of specific antigens.

The aim of the presented experiments was to estimate LIF production in the course of experimental infections with influenza viruses (of different degrees of adaptation), with S. aureus 209P and in the course of simultaneous viral-bacterial infections in mice. Spleen cells incubated with specific influenza antigens obtained according to Nath's method were used for the experiments as well as cells incubated with staphylococcal staphylolysine (Boehring Werke). The interdependence between LIF release and the degree of adaptation of viruses to lung tissue was observed. When influenza viruses APR-8 of high degree of adaptation to animal lung tissue were used, inconsiderable LIF production was observed in the early stage of observation. When the animals were infected with viruses A/Scotland/74 of low degree of adaptation, significant LIF production could be noticed since the 1st day of observation. Mixed, viral-bacterial infections influenced insignificantly LIF release. Its production was mainly conditioned by influenza viruses used for the infections.