Egg-adapted Strain Research Articles

The Propagation and Cytopathogenic Effect of an Egg-Adapted Strain of Infectious Bronchitis Virus in Tissue Culture

NFECTIOUS bronchitis (IB) is an acute and highly infectious respiratory disease of chickens. Economic losses are due to mortality and retardation of growth in young chicks and loss of production and egg quality in layers. Shalk and Hawn first described the disease and Bushnell and Brandly2 demonstrated its viral etiology. Beaudette and Hudsonl propagated the virus in embryonated eggs and Jungherr and Terrell7 demonstrated parental immunity in chicks. Jungherr et al.8 showed the existence of two antigenically different types of IB virus. Fahey and Crawley5 propagated IB virus in chicken-embryo tissues and monkeykidney cells but could not demonstrate a cytopathogenic effect (CPE). Buthala and Mathews3 could not show any CPE on a single passage of IB virus in chicken-embryo-kidney cells. In this work the growth of IBV virus in tissue culture was investigated by using serial blind passages in an attempt to produce CPE. This characteristic of the virus would be an added tool in the study of the virus.

Propagation of Measles Virus in Cultures of Chick Embryo Cells

This is a report from the laboratory of Dr. John F. Enders of the successful propagation of an egg-adapted strain of measles virus in cultures of chick-embryo cells throughout 24 serial passages. While the technical details will be of interest to experts in the field, the authors indicate that the quantities of measles virus which can be produced in chick cells is such that fluid from cultures of this type might provide appropriate material for the preparation of vaccine. The technique reported also has possible application to the assay of infectivity and the titration of antibodies for diagnostic and epidemiologic investigaton.

The Mechanism of Hemagglutination by Influenza Virus

This chapter is confined to the case of normal egg-adapted virus. Aberrant forms of the virus, such as the long rods that occur principally with freshly isolated strains and the incomplete, noninfectious virus produced when very large inocula are used also undergo the hemagglutination reaction in similar fashion to normal virus. Genetic variants of the virus can show vastly different abilities with respect to hemagglutination. Virus newly isolated from human sources, in particular, is very different in this respect from egg-adapted strains. The chapter is concerned with the dual property of hemagglutination and elution. It briefly describes the main features of the reactions and proposes scheme for the reaction. It has been that the ostensible simplicity of the hemagglutination reaction is, in reality, confused by a mass of diverse, and often contradictory, evidence.

Propagation of measles virus in cultures of chick embryo cells.

SummaryAn egg-adapted strain of measles virus has been propagated in cultures of chick embryo cells throughout 24 serial passages. Beginning with the 6th passage an abrupt decrease occurred in the time required to attain maximal concentration of virus in the fluid. The concentration of virus was comparable to that found in cultures of infected primate cells. In the 5th chick cell passage the virus began to produce cytopathic changes closely resembling those occurring in human epithelial cells infected with measles virus. The identity of the agent was confirmed in neutralization tests with measles antisera. In chick cells maintained with a medium of known composition virus production approached that in cultures nourished with serum and tissue extracts. Inoculation of rabbits with the virus propagated in chick cells was followed by development of neutralizing antibodies specific for the agent of measles.

Immunological relationship between measles and distemper viruses.

SummaryIn tissue culture studies, the Edmonston strain of measles virus was neutralized by distemper antiserum prepared in ferrets with the egg-adapted and mouse-adapted strains of distemper virus. All normal ferret sera failed to show any neutralization of measles virus. In animal studies, ferrets immunized with measles virus and subsequently challenged with virulent distemper virus showed some evidence of protection as revealed by prolonged incubation periods, modified illnesses and survivals. The mouse-adapted distemper virus was completely neutralized by measles antiserum prepared in ferrets, whereas, normal serum failed to show any neutralization. Mouse-adapted distemper virus was also neutralized by human measles convalescent sera. These results suggest that common antigenic components are shared by the viruses of measles and distemper.

インフルエンザウイルスの赤血球凝集能と感染能及免疫能との関連性

We studied the hemagglutinating activity, infectivity and immunizing ability of influenza virus FM1 (egg-adapted strain and mouse-adapted strain). The mouse-adapted strain FM1 had infectivity, immunizing ability and toxicity against chick embryo proportion to its hemagglutinating activity, but not against mice.After we repeated the adsorption of virus in virus-suspension with chick red cells, we inoculated the 10-1-10-5 dilution of that non-hemagglutinating supernatant into the chorioallantoic cavity of eggs, and, after 48 hours' incubation, we recognized the virus-production by their hemagglutination. So that there may be the non-hemagglutinating but infective influenza virus.

Infection of the one-day old fertile hen's egg with rabies virus. I. Growth curves and serial passages.

The mouse-fixed Takamen, moderately 1-day egg-adapted Nishigahara, 7-day egg passage HEP Flury strains of rabies virus and their highly 1-day egg-adapted sublines were inoculated into 1-day, 3-day, and 5-day eggs to examine the virus yields in the embryo. It was consistently observed that the 1-day egg infection could give the largest total amount, as well as the highest concentration of virus in the embryo. The moderately 1-day egg-adapted Nishigahara strain was found to be best fitted for the production of 1 -day egg vaccine, because the size of the embryos harvested was sufficiently large and the concentration of virus yielded therein was higher than could be obtained with other strains. The egg-infective properties of this particular subline of Nishigahara strain could be maintained by transferring this virus to mouse brain passage. Five lots of 1-day egg vaccine prepared with this strain by means of UV inactivation possessed Habel indices of more or less 1,000 LD. One of these lots showing the lowest Habel index turned out to have more than 7 times as high a potency as the U. S. reference vaccine when tested according to the U. S. Minimum Requirements.

Intracerebral inoculatior of mice with Newcastle disease virus.

The results of intracerebral inoculation of 25 strains of Newcastle disease virus (NDV) into weanling mice were reported in a previous communication.1 Some of the strains produced rapidly fatal involvement of the nervous system, while others had little effect upon the mice. The growth of strictly egg-adapted or chicken-adapted strains of NDV in weanling mice has not been detected,2,3 with a possible exception.4 Kilham5 was successful in serially passaging the 11914 and Vict strains of NDV in 3-day-old suckling mice. The finding of such differences in the response to NDV of young and mature mice prompted the present study in which the effect of strains of NDV of

インフルエンザ・ウイルスの赤血球凝集能と感染能及免疫能との関連性

We studied the hemagglutinating activity, infectivity and immunizing ability of influenza virus FM1 (egg-adapted strain and mouse-adapted strain). The mouse-adapted strain FM1 had infectivity, immunizing ability and toxicity against chick embryo proportion to its hemagglutinating activity, but not against mice.After we repeated the adsorption of virus in virus-suspension with chick red cells, we inoculated the 10-1-10-5 dilution of that non-hemagglutinating supernatant into the chorioallantoic cavity of eggs, and, after 48 hours' incubation, we recognized the virus-production by their hemagglutination. So that there may be the non-hemagglutinating but infective influenza virus.

Studies on Chick-Embryo-Adapted Rabies Virus

Summary Guinea-pigs injected with living egg-adapted Flury strain of rabies virus become resistant to challenge inoculation with street virus within 12 days after vaccination. This resistance is accompanied by the development of homologous neutralizing antibodies. Results of comparative immunization of dogs and guinea pigs indicate that the latter species may be used successfully to control potency of canine vaccines. The proposed potency control test is described in detail.

Studies on Herpes Simplex Virus

Summary A viable egg-adapted strain of herpes simplex virus was injected intravenously in large amounts in 11 human volunteers and attempts were made at various intervals thereafter to recover the virus from the blood by inoculation into fertile eggs. No significant amount of virus could be recovered by any method employed. The small amount of virus which was recovered after inoculation onto the chorioallantoic membrane could not be transmitted by serial passage in ovo. A complement-like heat labile substance was demonstrated in the plasma of one patient which inhibited the propagation of herpes virus in ovo. Neutralization tests performed on sera obtained from the individuals prior to the virus injection demonstrated marked differences in titer of neutralizing antibodies to herpes virus. In contrast to the previous findings that the antibody titer did not change after injection of inactivated herpes virus, the intravenous injection of viable virus resulted in significant rises in neutralizing antibody levels in 4 out of 9 persons. The role of antibody, the heat labile plasma factor and viral removal mechanisms is discussed. Egg-adapted strains of herpes virus failed to exhibit hemagglutination activity when tested in vitro against a wide variety of animal red blood cells, in contrast to the claims of Moolton et al.

Propagation of a strain of egg-adapted distemper virus in suckling mice.

SummaryTwo separate lines of the FXNO strain of egg-adapted canine distemper virus were passed intracerebrally in suckling mice 18 and 10 times, respectively. Both lines induced signs of protracted hyperkinesis. After the 7th passage central nervous system involvement became quite prominent and severe. Ataxia, muscular twitching, disequilibrium, paresis, and clonic spasms were common manifestations. The time of the first nervous disturbance decreased progressively from 8 days to 3 days in Line 1 and from 15 days to 4 days in Line 2. In ovo neutralization tests and ferret protection tests establish the identity of the mouse passaged agent with the original egg-adapted FXNO strain.

Cultivation of egg-adapted Theiler's mouse encephalomyelitis (TO) virus in chick tissue culture.

Summary1. An egg-adapted strain of Theiler's mouse encephalomyelitis virus (TO) has been carried through 42 passages in vitro on embryonic chick tissue. Attempts to adapt the mouse passage virus directly to chick tissue culture were unsuccessful. Preliminary growth in embryonated eggs, followed by tests in mice of 20% embryo suspensions, facilitated the titration of tissue culture fluids. 2. One of 3 strains of approximately the same mouse-infective titer failed to adapt either to egg or tissue culture. 3. A representative strain of Theiler's mouse encephalomyelitis (TO) virus obtained from the American Type Culture Collection also adapted to egg and tissue cultivation.

Studies on Herpes Simple Virus

Summary An egg-adapted strain of herpes simplex virus was used in a study of the neutralizing activity of human sera in the embryonated egg. The neutralization test employing lethal endpoints after the injection of virus-serum mixtures into the yolk sac was found to be simpler and more reliable than that employing the reduction of pock count on the chorioallantoic membrane. Undiluted serum neutralized disproportionately more virus than diluted serum. The neutralizing capacity of dilute human sera was greatly enhanced by incubating virus-serum mixtures for 1 hour at 37 C prior to injection. The procedure increased the neutralization index of different sera in varying degree and thus permitted their distinction.

The Immunising Properties of An Egg-Adapted Strain of Fowl Pox Virus

Summary The adaptation of a Kenya strain of fowl pox virus to the chorioallantoic membrane of embryonated eggs is described. When used as a vaccine, consisting of infected chorio-allantoic membranes suspended in glycerine and broth, the egg-adapted virus provoked a solid immunity, lasting at least twelve months against challenge with homologous scab virus. The egg-adapted vaccine remained viable for 6 to 12 weeks at room temperature and for 6 to 12 months at refrigerator temperature.

牛痘ヴイールスの孵化鶏卵内培養知見補遺

This study was performed in order to examine the method of cultivating vaccinia virus, and to obtain the egg-adapted strain of vaccinia virus, and practically to evaluate the possibility of vaccine lymph production using the embryonated hen's egg.1) When 5, 000 units of streptomycin and 500 units of penicillin G crystal were added into lml of vaccine lymph Tyrode suspension and then the mixture was inoculated into the allantoic fluid of chick embryo. As a result, it was found that the vaccinia virus could be propagated and all inoculated eggs were free from bacilli.2) The distribution of vaccinia virus at the each portion of the egg was examined. It was the infectious chorioallantoic membrane to possess the highest infective unit. The embryo was the same or a little lower compared with the chorioallantoic membrane. The allantoic fluid possessed the low unit and the yolk lower. This distribution of vccinia virus in the egg was principally the same when the egg addapted strain of vaccinsa virus (20 passages) was inoculated.3) The testicular strain of vaccinia virus pssessing the high infective unit (10-7) was inoculated into the allantoic fluid of 12 day's embry and incubated at 37°C for 3-4 days. The infectious chorioallantoic membrane which was obtained consequently, was used as the next inoculum. In the same way, the infectious chorioallantoic membrane of inoculated egg was used as an inoculum of the next generation. In this way, the author has succeeded the successine cultivation of vaccinia virus for 23 generations and obtained the egg adapted strain possessing high infective unit (10-15).4) The culture method of influenza virus in the empty egg which was devised by Bernkopf (1950) was used at the cultivation of vaccinia virus. As a result, the favorable multiplication of the virus was found in it.

Response of Man to Egg-Adapted Colorado Tick Fever Virus.

Twenty volunteers were inoculated with the egg-adapted strain of CTF living virus. Reactions ranged from enlarged, tender axillary lymph glands to single-episode attacks of illness resembling Colorado Tick Fever. Five of the inoculated individuals were subsequently challenged with a human strain of CTF living virus but they showed no reactions whatsoever to this second inoculation. All of the individuals developed neutralizing antibodies, but the 3 who presumably were immune prior to the inoculations showed a comparatively earlier and greater response. Sera obtained from the 3 individuals after they had been challenged with a human strain likewise showed a high neutralizing titer.

Studies on Chick-Embryo Adapted Rabies Virus

Summary The pathogenic properties of three egg-adapted strains of rabies virus (NYC, NIH and Flury) were studied in dogs. Administered intraneurally the NYC and NIH strains were more virulent than the Flury strain. The Flury strain was completely innocuous to dogs when inoculated either into the masseter or the thigh muscles. Vaccination of 76 dogs by the intramuscular route with preparations of the Flury strain of living rabies virus at various egg-passage levels indicated excellent immunogenic properties of the strain as judged by the results of challenge with street strain of rabies virus. The Flury strain was immunologically superior to the two other egg-adapted strains, also employed in the living stage for vaccination purposes. These findings are discussed in the light of possible use of the egg-adapted Flury strain living rabies virus for mass vaccination of the canine population.

Production of Hemagglutinin by Mumps and Influenza A Viruses in Suspended Cell Tissue Cultures.

Conclusions1. An egg-adapted strain of mumps virus has been cultivated in suspended cell tissue cultures. 2. In such media the mumps virus as well as Influenza A virus (PR8 strain) produce measurable quantities of hemagglutinin.

A Method Applicable to the Standardization of Influenza Virus Vaccines.

SummaryA procedure applicable to the standardization of influenza virus vaccines has been described. The total time required for completion of the test can be as little as 16 days. The procedure, referred to as the anti-genic extinction titration, determines the highest dilution of antigen capable of inducing the formation of demonstrable amount of virus-neutralizing antibody in the pooled serum of groups of 10 mice. The test for neutralizing antibody is carried out in ovo and may; therefore, be used in those instances in which the strain of virus that may be included in a vaccine has been adapted only to the chick embryo and is not pathogenic for mice.The use of chick embryos rather than mice as the indicator medium for virus neutralization offers the advantages of completion in 2 days rather than 10 days, applicability to egg-adapted strains and sharpness of results, as well as being less costly.The importance of maintaining the identity of virus in vaccine and virus used as test antigen for measuring t...