Freshly removed tissues of normal untreated mice produced relatively high amounts of interferon (IFN) in organ cultures. Lymph nodes, subcutaneous tissue, and the capsule of the kidney were the most active IFN producers. The abdominal wall and the thigh muscle were less active, whereas the lungs and spleen, similarly to the peritoneal exudate and bone marrow cells, produced only threshold amounts of IFN. Liver cultures did not produce IFN under these experimental conditions. Cultures prepared from IFN-pretreated animals produced three- to fourfold more IFN. Homogenates of tissue prepared immediately after their removal did not contain a detectable amount of IFN. The bulk of the IFN activity was produced during the first 6 h of incubation at 37 degrees C. Omission of serum from the culture medium, and the presence of 50 micrograms/ml of polymyxin B, did not inhibit IFN production. Cultures incubated at 0 degrees did not release any IFN. The IFN activity produced by all types of tissue was pH 2 resistant and it was neutralized by an antiserum to murine (Mu) IFN-beta. Different strains of mice produced comparable amounts of IFN under the present experimental conditions.
Two sublines of mouse L929 cells designated L929B and L929M were studied. The L929B cells, which displayed a 2-3-fold higher IFN production in response to Sendai virus than that of the L929M cells, had a higher sensitivity to the antiviral and priming effects of IFN and were more resistant to VSV. In good accord with the amount of IFN produced, more translatable IFN mRNA was isolated from the L929B cells. IFN production and IFN mRNA activities were proportionally increased in the IFN-primed cultures of both sublines. Results indicate that both inherent and priming-induced increased-IFN production are based on pretranslational control mechanisms.Interferon production Pretranslational control Priming e&3
We have studied the relative contribution made to the production of interferon (IFN) in vitro in response to Sendai virus by the cells of different types present in human peripheral blood, with particular emphasis on the amounts of poly(A) plus RNA extractable from each subpopulation and its content of IFN mRNA. Peripheral blood cells were fractionated by conventional techniques, and the amounts of IFN made after induction with Sendai virus were measured. The proportion of IFN-producing cells in the various fractions was determined by immunofluorescent staining. Poly(A) plus RNA was extracted from each population and the content of IFN mRNA determined by microinjection into Xenopus laevis oocytes. Information obtained in these three ways was essentially concordant, and showed that monocytes and E rosette-negative lymphocytes predominantly contribute to IFN production.
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