Several substances were reported to have chemoprophylactic effect on poliovirus infection in animals; e.g., benzimidazole, helenine, and statoln.
In a previous study in our laboratory, antitumor antibiotics such as quinomycin, miromycin, carzinostatin, and chromomycin A₃ were found to be effective prophylactically on poliovirus infection in mice. The present study revealed that carzinophilin exhibited a preventing effect on poliovirus infection in mice, and the mechanism of the prophylaxis was studied.
To examine the protective effect of carzinophilin, mice were injected intraperitoneally with 2, 500-10, 000u/kg of the antibiotic. Twenty-four hours later, the animals were challenged intraperitoneally with 10 LD₅₀ of virus. Mortality of the mice was reduced from 100% in the control group to 20 or 40% in the treated group with 2, 500 or 5, 000u/kg of carzinophilin. When mice were infected with 100 LD₅₀ of the virus, administration of carzinophilin did not prolong the life span of the animal, although it did appear to produce a delay in the onset of paralysis.
To examine the effect of carzinophilin on reproduction of poliovirus in the mouse brain, the following experiments were carried out. A group of mice was injected intraperitoneally with 10, 000u/kg of the agent 24 hours prior to the infection with 100 LD₅₀ of virus via intraperitoneal route. The treated and the control mice were sacrificed 24 hours after infection, and the amount of the virus present in the brain of each animal was determined. Virus titers in the brains of all control mice ranged from 10^4.6 to 10^5.5 TCD₅₀, whereas no virus titer was detected in the brains of seven out of eight treated mice and only one exhibited a virus titer of 10^5.5 TCD₅₀.
Other groups of mice were similarly pretreated with the agent, and the treated and the control mice were sacrificed 3 and 6 hours after infection. The virus titers in the liver and blood were determined, but no difference was observed between the treated and the control. No inhibition by carzinophilin of the virus reproduction in the brain was observed, when the virus was inoculated intracerebrally. Carzinophilin had no inactivating effect on the virus, and had no effect on the yield and cytopathogenicity of the virus in HeLa cells.
Finally, virus titers in the brain which was perfused with saline were examined as early as 3 and 6 hours after virus inoculation to determine the amount of virus adsorbed to or penetrated via the “blood-brain barrier”. At 3 hours, no difference was observed in the virus titer between the treated and the control mice, but an inhibition of virus growth was observed in the treated mice at 6 hours.
These results suggest that the prophylactic effect of carzinophilin on poliovirus infection may not be due to the inhibition of virus reproduction in target cells but due to the effect of the agent on the blood-brain barrier.

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Lipovirus is a new transmissible cytopathic agent, possibly isolated from the acute phase blood of an infectious hepatitis patient.
The optimal temperature for the development of specific degeneration in lipovirus-infected culture was 33°C. Partial and complete suppression was noted at 37°C and 38°C respectively. The lipovirus was lethal to chick embryos if the virus was inoculated into the amniotic or allantoic sacs or onto the chorioallantoic membrane and the embryos then incubated at 33°C. Inoculation into the yolk sac or elevation of incubation temperature to 38°C nullified the lethal action of the lipovirus on chick embryos. A little lipovirus replicated in the spleen and liver of artificial induced hypothermic mouse.
Consequently, the replication of the lipovirus in vitro, in ovo and in vivo was powerfully accelerated at 33°C, relatively low temperature and temperature elevation generally resulted in the suppression of virus multiplication.

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The course of influenza infection in mice with mouseadapted PR8 strain of influenza A virus was studied by means of immunofluorescent staining. Absolute 10^4.1 EID₅₀ amount of virus corresponding to 60 LD₅₀ was inhaled as aerosol into each mouse weighing 10g in average.
Obtained results can be summarized as follows:
1) Synthesis of virus antigens was restricted to the cells lining along bronchoalveolar tree, although the growth of virus in alveolar cells started some 12 hours behind that in bronchial cells.
2) In the late stage of infection, specific immunofluorescence was still detectable with alveolar cells. Whereas, new antigen synthesis was not detectable in newly built metaplastic cells along main bronchus.
3) Infiltration of rounded cells, probably lymphocytes and monocytes in origin, which plays dominant role to explain the histological characteristics of influenza pneumonia as interstitium pneumonitis, was found as in many other works. However, no specific fluorescence was detectable among the population of these rounded cells, this suggesting that these cell infiltrations are the reflection of the non-specific inflammation.

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It was shown that the several characters of Escherichia coli as well as of Salmonella typhimurium can be transfered from a donor cell to a recipient Salmonella by means of Chi phage mediated genetic transduction.
Transduction is performed by Chi particles grown on the donor strain through lytic cycle. No lysogenic bacteria for the transducing phage can be observed in all transductants. The proportion of ‘transduced’ cells to servival bacteria in this system is about 10^-7 for both S. typhimurium and E. coli. This number is smaller compared with those in other temperate phage systems.
The transduction of several amino acid and nucleotide synthesis markers were observed, but of galactose and lactose fermentation markers were not observed. It was posturated that there was no significance, difference in transducing efficiency among several characters employed in this experiment except some suger utilization activities.
From these results, it is concluded that the transduction by Chi phage is generalized type as observed with phage P22 in S. typhimurium and with phage P1 in E. coli. Colonies of the transductants appeared rather small in size than wild type colonies generally. It may suggest that the existance of unstable transduction in this system.
Further small but recognizable number of minute colonies could be demonstrated in these colonies by the use of enriched minimal medium for selection. These minute colonies show the unilinear transmission by streaking test. These phenomena may represent abortive transduction.
When the Chi phages were irradiated with U. V. light immediately before they were infected to the recipient cells, the transducing efficiency became higher at low doses of irradiation, but it fell down exponentially if higher doses were employed. After irradiation with U. V. light at the optimum dose, the efficiency of transduction increased two times of that attained by the unirradiated phages. The effect of U. N. irradiation on the transduction reversed at the dose of inactivation not less than 60 percent of plaque forming ability.
The relationships between the frequency of transduction and the amount of phages adsorbed to a recipient cell were examined. Optimal multiplicity of infection for the transduction are the range of 2 to 8 per bacterium. The numbers of transductants steeply decreased when the multiplicity of infection increased more than the optimal dose.
From the facts that the dependence of transducing dfficiency on the multiplicity of infection and the absence of lysogenic bacteria in transductants, it is concluded that the transducing particles are defective ones of Chi phage, in which a part of phage chromosomeis replaced by a chromosome fragment of a donor bacterium.

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Egg-propagated Newcastle disease virus (NDV), Miyadera strain, was neuropathic for mice in low and high dilutions. Multiplication of virus or incomplete virus synthesis did not occurred in the brain, and the disease was not transmissible by serial passage in mice.
Neuropathic effect would be caused by different activity from HA, infectivity, and hemolytic activity of the virus.
The effect seemed to parallel with the lung consolidation effect and the intestinal hemorrhage producing effect of virus in mice.
Prior intra-abdominal injection of chlorpromazine reduced the death ratio of mice resulting from the intracerebral inoculation of NDV.
Decrease of infectivity titer and relative increase of neuropathic effect of the virus were resulted from the sonic vibration.
The supernatant fluid of sonically vibrated virus preparation was neuropathic for mice even after the complete removal of the hemagglutinin.

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