Boosting vaccine for tuberculosis.

An effective new vaccine for the control of tuberculosis is badly needed. While current research attempts to improve vaccination are concentrating on new prophylactic or immunotherapeutic vaccines, virtually no emphasis has been placed on boosting individuals already inoculated with Mycobacterium bovis BCG. It is shown here that mice vaccinated with BCG gradually lose their capacity to resist an aerosol challenge infection as they age. However, if these mice are inoculated with the 30-kDa mycolyl transferase A protein in midlife, after challenge when aged they express levels of protection in the lungs comparable to those of young mice, associated with minimal pathological damage.