Process for the production of virus vaccine

A process for producing virus vaccine having a substantially diminished immunoglobulin E antibody producibility and remarkably enhanced producibility of immunoglobulin G and immunoglobulin M antibodies, said process comprising the steps of:

• providing a water-soluble polysaccharide selected from the group consisting of pullulan, elsinan, hydrolysates thereof, and mixtures thereof, said polysaccharide having a molecular weight from 1,000 to 100,000,000, and bearing a functional group capable of covalently linking with a pathogenic virus, said functional group being a member selected from the group consisting of carbodimide, imidocarbonate, halogenoalkyl, aldehyde and isocyanate groups, and aromatic amino groups in the form of diazonium salts;
• forming a water-soluble conjugate of a pathogenic virus and said polysaccharide by allowing one part by weight of the virus to react with 0.01 to 100 parts by weight of the polysaccharide at a pH in the range of 3 to 12 and a temperature in the range of 0.degree. to 100.degree. C. for 0.1 to 50 hours to thereby detoxify said virus;
• and
• recovering said water-soluble conjugate for use as a virus vaccine having a substantially diminished immunoglobulin E antibody producibility and remarkably enhanced producibility of immunoglobulin G and immunoglobulin M antibodies.