GB716920A - A process for the mass production and treatment of pathogenic viruses and substances which accompany them - Google Patents

Abstract

In the propagation of viruses, e.g. of foot-and-mouth disease, animal tissue in which the virus propagates selectively is fragmented and diluted, suitably with amniotic liquid, to form a suspension, and as such, introduced into the body of an animal susceptible to the virus, e.g. under the skin or into the abdominal or pleural cavity, wherein it is permitted to develop into a neoformation mass of substantial size, whereupon the virus is introduced into the animal, if desired, directly into the neoformation mass, and allowed to propagate until the neoformation mass becomes virulent, the latter is then removed, fragmented, undesired tissues being removed if desired, and ground until the cells are destroyed, preferably at low temperature. The selected tissues may be obtained from a foetus or adult animal; in the latter case, they should be treated with antiseptics or antibiotics. The virus may be modified by mixing it, prior to inoculation, with polysaccharides, viz. hyaluronic acid and its sulphuric esters such as chondroitine sulphate and mucoitine sulphate. These substances may alternatively be introduced into the embryone. The ground virulent tissue is mixed with the virulent liquids produced, filtered or centrifuged, and the desoxyribonucleoprotein fraction may be extracted by the action of concentrated sodium chloride; the ribonucleo-protein fraction can be extracted by acidification. All the nucleo-proteins may be precipitated with lanthanum choride. The globulin fraction may be precipitated by the addition of 50 per cent ethyl alcohol. All the proteins may be precipitated by dioxane or a mixture of alcohol and dioxane. Precipitation may also be effected by acetone or ammonium sulphate. The various fractions or the total residue may be dried in vacuo at low temperature or they may be absorbed on alumina gel. Filtered saliva of cattle and/or milk, alone or in association with glycerine, may be added to the virulent material before the solids are separated or proteins precipitated. The saliva is first treated with antiseptics, e.g. tricresol, phenol, formol, thymol, toluene, or sulphonamides or antibiotics, or it may be otherwise sterilized. The virulent matter, at various stages of its treatment, may be attenuated by the action of physical agents, e.g. temperature, ultra violet radiation, or by e.g. formaldehyde, or other agents such as d-glycuronic acid, d-glucurone, glucosamine, N-acetyl-d-glucosamine, glucosamine hydrochloride, galacturonic acid, or by tricresol, the isomeric cresols, quaternary ammonium derivatives, derivatives of p-hydroxybenzoic acid or of p-chlorobenzoic acid, hydroxyquinolinic acid, phenol, thymol or toluene. The virulent matter, mixed if desired with milk and/or saliva, and attenuated as indicated, may be preserved in the liquid state, or dried in vacuo. The dry material may be kept in sealed tubes in vacuo or in an atmosphere of nitrogen.