The nucleic acid fraction from cells of 6 species of bacterium and 2 kinds of vertebrate, calf and salmon, was extracted and purified by the same procedures as described previously. When the spleen cells from BALB/c mice were incubated with the nucleic acid fraction from either of the bacteria, natural killer (NK) activity of the cells was remarkably elevated and the cells produced factors to activate macrophages and to inhibit viral growth. It was shown that the factor to activate macrophages was interferon (IFN)-gamma and that to inhibit viral growth was IFNalpha/beta. On the other hand, the nucleic acid fraction from either of the vertebrate cells did not show such activities. Pretreatment of the bacterial nucleic acid fraction with DNase, but not with RNase, abrogated completely the biological activities. The activities of the bacterial nucleic acid were not influenced by the presence of polymyxin B, an inhibitor of lipopolysaccharide (LPS), and the spleen cells from not only BALB/c mice but also LPS-insensitive C3H/HeJ mice were activated, indicating that the activities of the fraction were not ascribed to LPS contaminated possibly into the fraction, but to DNA itself. Intralesional injection with the bacterial DNA fraction caused regression of mouse IMC tumors, but the injection with the vertebrate DNA fraction did not. These findings prompted us to examine the biological activities of DNA samples from a variety of animals and plants, which were provided from other laboratories or purchased from manufacturers. All of the DNA samples from cells of 5 kinds of bacterium, 2 of virus and. 4 of invertebrate augmented NK activity and induced IFN, more or less, in mouse spleen calls, while the DNA from 10 kinds of vertebrate, including 3 of fish and 5 of mammal, showed no such activities. The DNA from 2 species of plants, were also inactive. Possible mechanisms to explain the different biological activities of DNA from different cell sources were discussed based on our previous finding that the particular palindromic sequences with a G-C motif (s) are required for induction of IFNs and activation of NK cells with synthetic 30-mer oligonucleotides.We have demonstrated that a DNA-rich fraction, extracted fromMycobacterium bovis BCG and designated MY-1 (22), exhibited strong antitumor activities against 98 3

SynopsisDynamic mechanical and dielectric properties of various kinds of polystyrene, including bulk-polymerized, monodisperse, isotactic, and thermally degraded samples, have been measured below the glass temperature to 4'K. Five relaxation processes are found, designated 8, y, y ' , 6, and in order of descending temperature. The 8 peak (350'K at 10 kHz) is attributed to the local oscillation mode of backbone chains and the y peak (180°K at 10 kHz) to rotation of phenyl groups. The y' peak (100°K a t 10 kHz) is observed only in dielectric properties of the bulk-polymerized sample and is assigned to weak polar bonds, such as oxygen bonds in the chain. The 6 peak (55°K at 10 kHz) which is prominent in dynamic mechanical properties is interpreted in terms of lattice defects due to a syndiotactic diad inserted between isotactic sequences in a chain or vice versa. The E peak (ca. 25°K at 10 kHz) is first reported in the present work, but the mechanism involved is not yet clear.

Using gel retardation and in vitro "footprinting", we have analyzed the interactions between nuclear proteins derived from various mouse cells and the enhancer and interferon response sequences of the H-2Kb gene. We have found that a protein factor binds a site in the enhancer sequence that partially overlaps the interferon response sequence. This factor also binds to a similar sequence lying in the opposite orientation in the promoter of the mouse 132-microglobulin gene, suggesting a common regulatory mechanism. Transfection competition experiments indicate that this factor acts as a positive element in the expression of H-2 and 382-microglobulin genes.

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An enhancer binding factor, designated KBF1, has been purified from the nuclear extract of mouse BW5147 thymoma cells by five column chromatography steps including a sequence‐specific DNA affinity column. Gel retardation and footprint analysis have shown that purified KBF1 has a binding activity specific for both H‐2 and beta 2‐microglobulin enhancer sequences. After SDS‐polyacrylamide gel electrophoresis of the most purified preparation a 48‐kd protein showed, after elution and renaturation, a binding activity to both enhancer sequences. These findings suggest that the expression of both H‐2 and beta 2‐microglobulin genes utilizes a common regulatory mechanism.