关键词： Infectious Disease   Human Lymphocyte   High Multiplicity   Leukocyte Culture   Abortive Infection  

摘要： Human lymphocytes stimulated with phytohemagglutinin (PHA) acquired the ability to support the replication of poliovirus. The maximum number of cells producing virus in cultures of lymphocytes coincided with the peak of cellular RNA synthesis induced by PHA stimulation. In cultures infected with a high multiplicity of virus, the PHA-induced DNA synthesis of the lymphocytes was partially inhibited. The inhibition occurred when virus was added up to 3 days after initiation of the PHA-stimulated leukocyte cultures, but not after 3 days. Inhibition of DNA synthesis by poliovirus could also be demonstrated in leukocytes cultivated in the absence of PHA. Pre-incubation of the lymphocytes with poliovirus before stimulation with PHA resulted in enhanced inhibition of DNA synthesis. It is postulated that part of the inhibition of the response of lymphocytes to PHA results from an abortive infection of the cells before new cellular RNA synthesis begins.

关键词： Carbon Isotopes   Cell-Free System   Dactinomycin/pharmacology   DNA/biosynthesis   Hela Cells/drug effects   Hela Cells/metabolism   Leucine/metabolism   Poliovirus/drug effects   Poliovirus/metabolism   RNA/biosynthesis   RNA Nucleotidyltransferases   RNA, Viral/biosynthesis   Thiosemicarbazones/pharmacology   Thymidine/metabolism   Tritium   Uridine/metabolism   Viral Proteins/biosynthesis   Virus Replication/drug effects  

摘要： Since N -methylisatin-β-4′:4′-dibutylthiosemicarbazone (busatin) has been reported to inhibit the replication of RNA viruses, we investigated its mechanism of inhibition of poliovirus synthesis in HeLa cells. It was observed that busatin inhibited the growth and DNA synthesis, but not RNA synthesis, of HeLa cells. In addition, busatin blocked poliovirus (types 1, 2, and 3) replication and viral RNA synthesis at any time in the replication cycle. Furthermore, busatin directly inhibited the cell-free, polio RNA polymerase reaction which differentiates it from other polio inhibitors such as guanidine and 2-(α-hydroxybenzyl)benzimidazole. Both the inhibition of cellular DNA synthesis and polio RNA synthesis could be reversed by washing the treated cells free of busatin. The parent compound, isatin-β-thiosemicarbazone, neither inhibited poliovirus replication nor the in vitro polymerase reaction. It is concluded that busatin blocks poliovirus replication not as a consequence of a toxic effect on HeLa cells, but by causing a discrete lesion in viral RNA synthesis.

关键词： Sulphate   Infectious Disease   Epidemiological Study   Strong Correlation   Dextran  

摘要： Gliotoxin was shown to exert a less inhibitory effect on standard virulent type 1 and 2 poliovirus strains than on attenuated homotypie strains. This did not apply to type 3 standard strains since the virulent Saukett virus proved to be inhibited to the same degree as the attenuated Leon 12a1b, WM III and USOL D bac strains. An increase in gliotoxin-resistance after several intra-human passages of different live polio vaccine strains occurred only in a vaccinee fed the type 1 LSc2ab strain.A strong correlation between the gliotoxin marker and therct/40 andMS characters was found in type 1 and 2 poliovirus strains isolated from patients and vaccinees. No correlation was observed between thegli marker and thermoinactivation at 50°C or sensitivity to dextran sulphate, guanidine and *** covariation between therct/40 andgli characters seems to be asymmetrical sinceglir mutants of the LSc2ab strain maintained theirrct/40− character, whilerct/40+ mutants of the same parental strain displayed increased gliotoxin-resistance. The value of thegli marker for genetic and epidemiological studies is discussed.

摘要： Poliovirus-infected FL cells, incubated at 28°C, were examined by electron microscopy. The immunofluorescent antibody technique was employed for detection of the intracellular viral antigen. Electron micrographs of cells from infected cultures showed both extensive cytoplasmic and nuclear alterations. Virus crystals were observed not only in the cytoplasm but also in the nucleus of cells 14-20 hours after infection. Intracytoplasmic crystals consisted of dense particles, approximately 27 mμ in diameter, suggesting mature virus particles, while intranuclear crystals were composed of empty particles with a less dense central area. Nuclei were stained specifically by fluorescent antibodies as small brilliant foci, suggesting that the intranuclear crystals possess the same antigenicity as the viral antigen. As judged by their size, structure and antigenicity, the intranuclear virus-like particles probably represent an incomplete form of the virus.

关键词： Infectious Disease   Healthy Child   Intermediate Position   Sewage Sample   Satisfactory Correlation  

摘要： Antigenic and rct/40 markers were examined of 66 strains of type 2 poliovirus, 39 of them originating from stools of healthy children, and 27 from sewage samples. Seven of the strains were also tested for monkey neurovirulence. There was no satisfactory correlation between the twoin vitro markers. The 7 strains tested for neurovirulence were shown to occupy an intermediate position between highly neurovirulent “wild” strains and highly attenuated “oral vaccine-like” strains. The correlation between neurovirulence and rct/40 marker was better, although not absolute, than between neurovirulenee and antigenic marker. The sudden reappearance of type 2 in the second half of 1965 is discussed.

关键词： Calcium   Phosphate   Infectious Disease   Parental Strain   Chromatographic Analysis  

摘要： Three types of mixed populations of poliovirus type 1 (strain Brunhilde) and type 3 (strain Saukett) were prepared. These populations were separated on calcium phosphate columns and the adsorption patterns studied. The adsorption patterns of double-neutralizable particles represented the average of the adsorption patterns of the parental strains. Chromatography separated double-neutralizable particles of the three types of mixed populations were cultured. They produced a mixed population consisting of particles neutralized by serum against strain Brunhilde, of particles neutralized by serum against strain Saukett, and of doubleneutralized particles.

关键词： Infectious Disease   Formalin   Theoretical Implication   Poliomyelitis   Practical Conclusion  

摘要： Monovalent inactivated poliomyelitis vaccines were exposed to 40° and 45°C for different times. Two pools of each of the three poliotypes were tested. It could be shown, that the decrease of the D-antigen value upon heating was slower than the decrease of the antigenic potency as determined in chickens. A difference between the three poliotypes existed, type II and type III showing a more thermostable D-antigen than type I. This was confirmed by immunoelectrophoresis experiments. A difference in thermostability between the three types was not detected in the chicken *** other pools, one of each poliotype, were submitted to a prolonged inactivation (Formalin 1/4000, 36°–37°C, pH 7.0) after the usual 12 days. Again the same discrepancy between the behaviour of the D-antigen and the antigenic potency *** some theoretical implications which are briefly discussed, these results lead us to the practical conclusion, that for testing inactivated poliovaccines, especially expired vaccines, the D-antigen determination is not reliable. However, this method can be very helpful as a guide during the production of the *** make sure that the precipitation lines found with the vaccines which were exposed to the two temperatures were D-lines some tests were performed, in one of which we used anti D-sera of a different origin. No indication was found, which could give rise to doubt about the nature of the lines under these conditions.

关键词： Amino Acids/metabolism   Antimetabolites/pharmacology   Carbon Isotopes   Centrifugation, Density Gradient   Guanidines/pharmacology   Hela Cells   Hot Temperature   Poliovirus/drug effects   Poliovirus/growth & development   Ribonucleases/pharmacology   Tritium   Trypsin/pharmacology   Uridine/metabolism   Viral Proteins   Virus Replication/drug effects  

摘要： The kinetics of the in vitro assembly of 14 S particles into 73 S empty capsids was studied in cytoplasmic extracts made from poliovirus-infected HeLa cells. The formation of 73 S particles is complete after 10–15 minutes at 37°. About 20% of the 14 S material appears to be defective. An attempt was made to identify the component(s) in infected cell extracts that are responsible for the assembly activity by testing its sensitivity to various agents. Extracts treated with sufficient ribonuclease to destroy the cell ribosomes are able to assemble 73 S particles from 14 S particles. Pretreatment of the extracts with metabolic poisons (NaCN, NaF) or inhibitors of protein synthesis has no affect on assembly activity. The assembly activity of extracts is inactivated by 50° for 20 minutes or pretreatment with trypsin or deoxycholate. Extracts in which the endogenous 14 S to 73 S assembly has been completed by preincubation retain their ability to assemble newly added 14 S particles.

关键词： Infectious Disease   Triphosphate   Thermal Denaturation   Partial Purification   Marked Dependence  

摘要： The RNA synthetase induced upon infection of HEp-2 cells with poliovirus has been partially purified. The 30-fold purified enzyme is activated upon addition of poliovirus RNA. It shows marked dependence on the four ribonucleotide triphosphates, being able to synthesize RNA for at least 60 minutes. The product formed is alkali labile. Treatment with exogenous RNase hydrolyzes the product partially, but after thermal denaturation its degradation is complete.