There is provided a method of identifying a protective Leptospira vaccine composition, comprising determining that the composition contains a protective concentration of a Lipl32 epitope polypeptide, for example, of a polypeptide comprising SEQ ID NO:13 or an antigenic variant or portion thereof. There is also provided a vaccine composition comprising a protective concentration of at least one Lipl32 epitope polypeptide having up to 250 amino acids and comprising SEQ ID NO:13 or an antigenic variant or portion thereof. There is further provided a method of identifying an immunogenic element in a vaccine composition comprising submitting the composition to a two-dimensional liquid chromatography mass spectrometry (2D LC/MS) process.
