Modified immunogenic pneumolysin compositions as vaccines

This invention relates to the field of vaccines, and in particular, methods for the production of modified forms of pneumolysin and their use in producing compositions for the immunization of mammals against infections caused by bacteria including This invention relates to modified pneumolysin polypeptides that retain the immunogenic nature of pneumolysin but have reduced or undetectable hemolytic activity compared to native pneumolysin. The invention also provides a method for generating novel pneumolysin variants with these desired characteristic properties. The invention also provides immunogenic compositions useful as pharmaceutical compositions including vaccines in which non-toxic, modified pneumolysin is used to stimulate protective immunity against The vaccines may be compositions in which the modified pneumolysin is conjugated to bacterial polysaccharides or may be carried on an attenuated viral vector. In addition, the invention also provides a method of using the non-toxic, modified pneumolysin toxoid in order to stimulate antibodies against in a treated individual which are then isolated and transferred to a second individual, thereby conferring protection against in the second individual.