Hemagglutination with the GDVII strain of mouse encephalo myelitis virus

Studies of mouse polyoma virus infection. IV. Evidence for mucoprotein erythrocyte receptors in polyoma virus hemagglutination

Treatment of guinea pig erythrocytes with types A and B influenza viruses rendered them inagglutinable by polyoma virus; also, the inhibitory effect of ovomucin on polyoma virus hemagglutination was destroyed by pretreatment of the ovomucin with various myxoviruses. These results indicate that polyoma virus and myxovirus erythrocyte receptor sites are identical. However, no destruction by polyoma virus of its own or of myxovirus receptors or inhibitors was detected. No serologic relationship was detected between polyoma virus and members of the myxovirus group; differences in size and stability further indicate their distinctness. No evidence was found of biologic or serologic relationship of polyoma virus with encephalomyocarditis virus or mouse encephalomyelitis virus.

The influence of the age of the host on local virus multiplication and on the resistance to virus infections

1. The susceptibility of mice of different ages to intramuscular, intraperitoneal, and oral administration of EMC virus, and to intracerebral and intramuscular injection of both the Texas and the Connecticut-5 strains of Coxsackie virus have been studied. In all cases susceptibility decreases with age. The development of resistance to a given virus may vary in rate and extent according to the route by which the virus is given.

2. The multiplication of small amounts of EMC virus in muscle, and of the Texas and Connecticut-5 strains of Coxsackie virus in both muscle and brain, has been studied in mice of different ages. A very high degree of multiplication of all three viruses was observed in both muscle and brain of young mice, but no significant multiplication of the EMC virus in older muscle could be detected with these small inocula, nor of either of the Coxsackie strains in older muscle or brain.

3. Multiplication of EMC virus in young mice was shown to take place within the muscle itself. Haemagglutination tests showed that less haemagglutinin, as well as less infective virus, was produced in the muscles of older mice following the injection of small amounts of virus.

4. Multiplication of EMC and GDVII viruses could be demonstrated even in older mice if a sufficiently large amount of virus was inoculated initially.

5. The rapid initial disappearance of infectivity from the site of inoculation was shown to be mainly due to dispersal of inoculated virus around the body.

6. The simplest hypothesis which will accommodate the observed data on virus multiplication and on the development of resistance with age appears to be that the accessibility of the host cell to virus decreases with age. We found no evidence that the ability of the host cell to support virus multiplication declines with age.

This work was done in the Department of Zoology, Oxford University. One of us was in receipt of a Medical Research Council training grant. The expenses of the research were met by a grant from the Nuffield Foundation, to whom we should like to express our gratitude.

Hemagglutination with arthropod-borne viruses

Through the use of acetone and ether extraction of brain tissue from newborn mice infected with certain arthropod-borne viruses, it has been possible to demonstrate hemagglutinins for chick erythrocytes associated with the following viruses: dengue Type 1, dengue Type 2, Eastern equine encephalitis, Ilhéus, Japanese B, Ntaya, St. Louis, Sindbis, Uganda S, Venezuelan equine encephalitis, West Nile (Egypt 101 strain), Western equine encephalitis, and yellow fever (viscerotropic and neurotropic strains). On the basis of the temperature and pH required for reaction, the viruses can be assembled in two groups: A-those that require 37 degrees C. and a pH of about 6.4, comprising Eastern, Venezuelan, and Western equine encephalitis and Sindbis viruses; and B-those that require either 4 degrees or 22 degrees C. and a pH of about 7.0, comprising dengue Types 1 and 2, Ilhéus, Japanese B, Ntaya, St. Louis, Uganda S, West Nile, and yellow fever viruses. A method of eliminating non-specific inhibitory substances present in sera was developed. The method consists essentially of filtration through Seitz pads. Extensive serological crossings were found among viruses of each group, while antisera of one group failed consistently to cross-react with antigens of the other. Antisera deriving from animals immunized with certain viruses for which no hemagglutinins could be developed by the present method, reacted with members of either one or the other group. Thus Semliki Forest virus would appear to belong to Group A, and Russian Far Eastern and louping ill viruses to Group B.

Inhibition of Theiler's encephalomyelitis virus (GDVII strain) of mice by an intestinal mucopolysaccharide. I. Biological properties and mechanism of action

A mucopolysaccharide has been obtained from intestinal tissue of adult mice which inhibits both infectivity and hemagglutination of Theiler's GDVII strain of encephalomyelitis virus of mice. The inhibitor is inactive against the FA and TO strains of Theiler's virus and against the Lansing strain of poliomyelitis virus. In the adult mouse, large amounts of the inhibitor are found only in the small intestine. The small intestine of infant mice, however, contains a considerably smaller amount of inhibitor. Inhibition, both in vivo and in vitro, appears to be the result of an interaction between virus and inhibitor. The intestines of man, monkey, rabbit, rat, cotton rat, hamster, sheep, cow, and pig contain relatively little inhibitor whereas guinea pig intestine contains as much as adult mouse intestine. An enzyme was found in the feces of mice, and several other animals, which is capable of destroying the inhibitory activity of the mucopolysaccharide with the liberation of reducing sugars.