Process for preparing conjugate vaccines including free protein and the conjugate vaccines, immunogens, and immunogenic reagents produced by this process

Abstract

A process for preparing a protein-polysaccharide conjugate includes reacting a protein with a polysaccharide to produce a mixture including a protein-polysaccharide conjugate and free protein. At least one unreacted reagent or low molecular weight component is removed from this mixture, without removing all of the free protein, to provide a purified mixture that contains the protein-polysaccharide conjugate and free protein. This purified mixture can be used as a conjugate vaccine, immunogen, or immunological reagent. Keeping the free protein in the purified mixture with the conjugate saves time and money in the conjugate production process. In another aspect of the invention, the purified mixture of the protein-polysaccharide conjugate and free protein is reacted with a hapten to produce a conjugate mixture including a hapten-protein conjugate and a hapten-protein-polysaccharide conjugate. Alternatively, the hapten-protein conjugate can be prepared first, this conjugate then reacting with a polysaccharide reagent to produce the conjugate mixture. This conjugate mixture can be treated further to remove the free hapten. The conjugate mixture, including the hapten-protein-polysaccharide conjugate and the hapten-protein conjugate, also can be used as a conjugate vaccine, immunogen, or immunological reagent.

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