Haemophilus influenzae b polysaccharide exotoxoid conjugate vaccine

Abstract From the Canadian patent

A water-soluble covalent polysaccharide-exotoxoid conjugate having a molecular size between 140,000 and 4,500,000 dalton and a ribose/protein ratio between 0.25 and 1.00, capable of producing T-cell dependent antibody response to polysaccharide from H. influenzae b is, prepared by mixing a derivatized diphtheria or tetanus toxoid in a substantially cyanogen halide-free solution with a cyanogen halide-activated capsular H. influenzae b polysaccharide hapten consisting of approximately equimolar amounts of ribose, ribitol and phosphate which polysaccharide had previously been heat sized until more than 60% attained a molecular size between 200,000 and 2,000,000 dalton.