Mary Wilson
Well-known member
Can J Comp Med Vet Sci. 1953 Mar; 17(3): 97–104.
Division of Animil Pathology, Canada Department of Agriculture, Animal DIfeases Resareb Institute, Hull, P.Q.
PMCID: PMC1791522
PMID: 17648626
Chas. A. Mitchell, R. V. L. Walker, and G. L. Bannister
Within recent years two broad lines of approach have been followed which have as their objective the production of biological agent scapable of stimulating resistance against specific virus invasion. One depends on transforming the virus from an agent which produces a fully developed pathological process into one which at most will induce a slight, transient, and non-symptomatic infection. The other depends upon propagating the virus on an extensive scale and in one way or another making it available in sufficient concentration. Inactivation of its disease producing properties by chemical or other means is carried out with- out destruction of antigenicity.
The first method depends on the adaptation of a virus to a foreign host. This usually results in a progressive increase of virulence in the new host with a corresponding loss of pathogenicity for the original host. Finally a point is reached where it may be inoculated into the original host without producing a progressive infection. It does, however, induce immunity. Examples of this method are Theiler's adaptation of yellow fever virus (1), Alexander's adaptation of horsesickness virus (2) and the adaptation to yolk sac of rinderpest virus by JenkinsandShope (3).
The other approach does not contemplate altered virulence although this may sometimes occur. This approach is in reality one of determining practical methods of producing economically a sufficiency of virus of appropriate concentration to be inactivated later. Examples of this type are propagation of encephalomyclitis virus in chick embryo (4) and the cultivation in tissue culture of the virus of foot and mouth disease (5).
The many trials under various conditions seem to indicate that in general there is a tendency for cells of the embryo or of the young to be more susceptible to virus invasion. Perhaps these cells are more permeable and possess more active enzyme systems.
For some time the authors have given consideration to the possibility of employing the mammary gland of the cow for the propagation of virus. This organ is in some respects an artificial one. Over the years and for economic reasons, efforts have been made by selective breeding to develop a gland capable of giving the maximum amount of milk until at present the organ is far removed from that which its primary function required. This has resulted in a structure whose cell likely possess not only active enzyme systems but are readily adaptable to varying conditions. In view of these characteristics, it was thought possible that some cels of the organ might lend themselves to the propagation of virus. Accordingly, it was considered desirable to conduct several preliminary trials using three different viruses which are not known to be pathogenic for cattle. ...
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1791522/?page=1
Full study:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1791522/pdf/vetsci00208-0002.pdf
Division of Animil Pathology, Canada Department of Agriculture, Animal DIfeases Resareb Institute, Hull, P.Q.
PMCID: PMC1791522
PMID: 17648626
Chas. A. Mitchell, R. V. L. Walker, and G. L. Bannister
Within recent years two broad lines of approach have been followed which have as their objective the production of biological agent scapable of stimulating resistance against specific virus invasion. One depends on transforming the virus from an agent which produces a fully developed pathological process into one which at most will induce a slight, transient, and non-symptomatic infection. The other depends upon propagating the virus on an extensive scale and in one way or another making it available in sufficient concentration. Inactivation of its disease producing properties by chemical or other means is carried out with- out destruction of antigenicity.
The first method depends on the adaptation of a virus to a foreign host. This usually results in a progressive increase of virulence in the new host with a corresponding loss of pathogenicity for the original host. Finally a point is reached where it may be inoculated into the original host without producing a progressive infection. It does, however, induce immunity. Examples of this method are Theiler's adaptation of yellow fever virus (1), Alexander's adaptation of horsesickness virus (2) and the adaptation to yolk sac of rinderpest virus by JenkinsandShope (3).
The other approach does not contemplate altered virulence although this may sometimes occur. This approach is in reality one of determining practical methods of producing economically a sufficiency of virus of appropriate concentration to be inactivated later. Examples of this type are propagation of encephalomyclitis virus in chick embryo (4) and the cultivation in tissue culture of the virus of foot and mouth disease (5).
The many trials under various conditions seem to indicate that in general there is a tendency for cells of the embryo or of the young to be more susceptible to virus invasion. Perhaps these cells are more permeable and possess more active enzyme systems.
For some time the authors have given consideration to the possibility of employing the mammary gland of the cow for the propagation of virus. This organ is in some respects an artificial one. Over the years and for economic reasons, efforts have been made by selective breeding to develop a gland capable of giving the maximum amount of milk until at present the organ is far removed from that which its primary function required. This has resulted in a structure whose cell likely possess not only active enzyme systems but are readily adaptable to varying conditions. In view of these characteristics, it was thought possible that some cels of the organ might lend themselves to the propagation of virus. Accordingly, it was considered desirable to conduct several preliminary trials using three different viruses which are not known to be pathogenic for cattle. ...
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1791522/?page=1
Full study:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1791522/pdf/vetsci00208-0002.pdf