Method for isolating and purifying transferrin and lactoferrin receptor proteins from bacteria and the preparation of vaccines containing the same

DETAILED DESCRIPTION The present invention overcomes the problems and disadvantages of the prior art by providing a method for isolating and purifying the lactoferrin and transferrin receptor proteins thereby facilitating the production of vaccines containing the lactoferrin and/or transferrin receptor proteins.
It is an object of the invention to provide a method for identifying lactoferrin and transferrin receptor proteins in bacterial pathogens and isolating and purifying the same.
It is also an object of the invention to provide single component vaccine antigens that are effective in the prevention of diseases caused by bacterial pathogens containing lactoferrin and transferrin receptor proteins.
It is a further object of the invention to provide vaccine antigens that are effective in preventing bacterial pathogen diseases in young children.
It is an additional object of the invention to provide vaccine antigens that exhibit superior immunological memory to current polysaccharide capsular vaccines.
Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
The objects and advantages of the invention will be realized and attained by means of the instrumentalities and combinations, particularly pointed out in the appended claims.
To achieve the objects and in accordance with the purpose of the invention, as embodied and broadly described herein, the present invention provides a method for isolating and purifying lactoferrin and transferrin binding proteins in membrane preparations from strains expressing lactoferrin and/or transferrin binding activity by an affinity chromatography method described herein.
The present invention also provides vaccine antigens containing a preparation of purified lactoferrin and/or transferrin receptor proteins.
A lactoferrin receptor vaccine antigen is provided comprising a preparation selected from the group consisting of (1) a purified lactoferrin receptor protein isolated from a bacterium or an organism expressing a cloned lactoferrin receptor gene, (2) a derivative of a purified lactoferrin receptor protein, (3) a fusion protein containing all or part of a coding sequence of a lactoferrin receptor gene, and (4) a synthetic peptide whose amino acid sequence is based on the amino acid sequence of a purified lactoferrin receptor or on the nucleotide sequence of a cloned receptor gene