The invention relates to a novel adjuvant Mycobacterium w and or its constituents and adjuvant containing composition, which contains antigen (s) with pharmaceutical acceptable carrier and its uses. Mycobacterium w and or its constituents when administered with antigen (s) to mammal results in enhanced immunogenicity of antigen. The enhanced immunogenicity manifests as humoral responses as well as cell mediated immunity. The adjuvant effect is seen with variety of antigens in various mammals irrespective of their immune status at the time of administration of Mycobacterium w and antigen containing composition. e.g. immune naïve or preimmunized status.
