An antigenic composition comprises at least one antigen, wherein said at least one antigen comprises at least part of a protein selected from EndoSe of Streptococcus equi subsp. Equi, EndoSz of Streptococcus equi subsp. zooepidemicus, and Endo S of Streptococcus pyogenes, and wherein said at least part of said protein comprises at least one antigenic epitope. A vaccine composition comprising the antigenic composition as immunizing component, methods for producing the antigeninc composition and the vaccine composition, use of the vaccine composition for prophylactic and therapeutic treatment, and an antibody preparation comprising monoclonal or polyclonal antibodies specific for an antigen or antigens of the antigenic composition are also disclosed.
