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H ITOH

Publications and source records attributed to H ITOH.

14 recordsLinked to original sources
PubMed1959

Double infections of single cells with ECHO 7 and Coxsackie A9 viruses.

Virus particles derived from single cells infected with two enteroviruses have been studied. Evidence was obtained to indicate that phenotypic, but not genotypic, mixing occurs between Coxsackie A9 (CAP) and ECHO 7 (E7) viruses. Monkey kidney cultures in monolayer were doubly infected with high multiplicities of CA9 and E7 viruses. During the latent period, the infected cells were suspended, diluted, and distributed under oil into droplets each containing a single cell, as checked by microscopic observation. The virus particles released by individual cells into the microdrop were characterized in differential plaque neutralization tests. Fifteen per cent of the microdrops contained doubly neutralizable particles, 53 per cent yielded either CA9 or E7 particles, and 34 yielded particles of an intermediate character (deficits between 37 and 75 per cent). On passage, the doubly neutralizable particles yielded progeny of both parental types. All passage strains behaved like the corresponding parent strain as regards pathogenicity for newborn mice, which is to say that this property was limited to virus particles with CA9 antigenicity. Coxsackie A9 has a more rapid growth cycle than ECHO 7 in rhesus monkey kidney cell cultures, and a slower one in patas cultures. In rhesus, when E7 virus was added first, CA9 could be added up to 2 hours later, and still a significant number of cells yielded either CA9 or doubly neutralizable virus. The converse was observed in patas cells.

Animals↗
PubMed1957

The infection of chimpanzees with ECHO viruses.

The oral and parenteral infections of chimpanzees receiving echo Types 6 and 4 viruses successively are described. The two infections, spaced 2(1/2) months apart, and given by the same route in each animal, failed to induce overt disease. The inapparent infections were demonstrated by virus excretion in the throat and the stools and the development of neutralizing antibodies. Complement-fixing antibodies also appeared after Type 6 infection, but fell more rapidly than the neutralizing antibodies. After oral infection, echo-6 virus was found for equal periods in both the throat and feces, but echo-4 persisted in the throat for much longer periods than in the lower bowel. Almost no virus carriage occurred after parenteral inoculation. No true viremia was exhibited in any of the animals. One of the chimpanzees had neutralizing antibodies against Type 6 virus in its pre-inoculation serum. It responded extraordinarily to the Type 6 exposure, developing antibody levels of 1:50,000 to echo-6, of 1:1024 against the echo-6' variant, and of 1:64 against the echo 6'' variant. Although Type 4 antibodies developed after the exposure, they proved difficult to measure by ordinary methods. However, they could be satisfactorily assayed by the plaque reduction method. Three other chimpanzees fed echo-2, echo-3, and an untypable echo virus, respectively, yielded results confirming those established with Types 4 and 6.

Animals↗