Investigation on extracellular slime from Pseudomonas aeruginosa as interferon inducer in mice

The investigation concerns interferon (IFN) production in the sera and spleens of 129/Ao/Boy mice induced with Pseudomonas aeruginosa slime extract. Interferon was present in the serum as early as 2 h after i.v. and i.p. injection of the immunogenic dose of the slime - 100 micrograms/mouse. Likewise, in the spleen the same dose induced interferon production at the second hour after its administration. In the spleen interferon was synthetized longer, even up to 7 days. On the other hand, it disappeared from the serum after 24 h. In vitro investigations on interferon induction in peritoneal cells and spleen revealed that after slime extract stimulation, only non-adherent cells are capable of IFN production; while adherent cells are not. Interferon synthesis in peritoneal cells in vitro was much enchanced if for the experiments, cells isolated 2 - 4 h after i.v. administration of mice with Ps. aeruginosa slime extract, were used. Besides, the stimulatory effect of the extract on interferon production was well marked in the Newcastle virus-induced peritoneal cells. For comparison, interferon obtained after induction with slime extract in vivo (in the serum) and in vitro (in peritoneal cells) was tested for its properties. The interferons although both acidstable, displayed significant differences. IFN obtained in vitro from peritoneal cells culture appeared thermolabile and susceptible for neutralization with gamma-globulin of rabbit serum against interferon from Newcastle virus-induced L929 cells (anti-MuIFN alpha/beta). IFN from serum was thermostabile, undergoing only slight neutralization with anti-MuIFN alpha/beta globulin.