Abstract: Immunogenic conjugates of a 38,000 daltons or 40,000 daltons outer membrane protein of H. influenzae type b and oxidized polyribosyl-ribitol-phosphate polysaccharide fragments of H. influenzae type b are disclosed. Vaccines containing the conjugates are disclosed as useful in immunizing against H. influenzae type b caused disease. Method for isolating and purifying the 38,000 daltons and 40,000 daltons outer membrane proteins and for preparing the oxidized polyribosyl-ribitol-phosphate polysaccharide fragments are also disclosed.

Abstract: A process for the isolation and purification of immunologically active polyribosyl ribitol phosphate (PRP), the capsular polysaccharide of Haemophilus influenzae type b. The PRP has been purified with ethanol, Cetavlon (hexadecyltrimethyl ammonium bromide) and a phosphate containing adsorbent, hydroxylapatite. The contaminants (nucleic acid, proteins and endotoxins) are removed to the minimum level by a treatment with hydroxylapatite. Also described is a process for the preparation of a combined vaccine containing the PRP (prepared as aforementioned) and B. pertussis antigens. The vaccine elicits anti-PRP antibody and antipertussis antibody (as measured by microagglutination) formations in young animals. This sera with anti-PRP antibody exhibits a strong bactericidal activity.