Abstract: An immunogenic agent which comprises a killed strain of Burkholderia pseudomallei, or a combination of components thereof which combination produces a protective immune response in an animal to whom it is administered, and which comprises at least two members selected from the group consisting of (i) a lipopolysaccharide of Burkholderia pseudomallei, (ii) a capsular polysaccharide of Burkholderia pseudomallei and (iii) a protein of Burkholderia pseudomallei or an immunogenic variant thereof or an immunogenic fragment of either of these, or a nucleic acid which expresses said protein, immunogenic variant or immunogenic fragment thereof in a host animal; for use in the prevention or treatment of infection by Burkholderia pseudomallei and/or Burkholderia mallei.

Abstract: An immunogenic agent which comprises a killed strain of Burkholderia pseudomallei, or a combination of components thereof which combination produces a protective immune response in an animal to whom it is administered, and which comprises at least two members selected from the group consisting of (i) a lipopolysaccharide of Burkholderia pseudomallei, (ii) a capsular polysaccharide of Burkholderia pseudomallei and (iii) a protein of Burkholderia pseudomallei or an immunogenic variant thereof or an immunogenic fragment of either of these, or a nucleic acid which expresses said protein, immunogenic variant or immunogenic fragment thereof in a host animal; for use in the prevention or treatment of infection by Burkholderia pseudomallei and/or Burkholderia mallei.

Abstract: An immunogenic agent which comprises a killed strain of Burkholderia pseudomallei, or a combination of components thereof which combination produces a protective immune response in an animal to whom it is administered, and which comprises at least two members selected from the group consisting of (i) a lipopolysaccharide of Burkholderia pseudomallei, (ii) a capsular polysaccharide of Burkholderia pseudomallei and (iii) a protein of Burkholderia pseudomallei or an immunogenic variant thereof or an immunogenic fragment of either of these, or a nucleic acid which expresses said protein, immunogenic variant or immunogenic fragment thereof in a host animal; for use in the prevention or treatment of infection by Burkholderia pseudomallei and/or Burkholderia mallei.

Abstract: An immunogenic agent which comprises a killed strain of Burkholderia pseudomallei, or a combination of components thereof which combination produces a protective immune response in an animal to whom it is administered, and which comprises at least two members selected from the group consisting of (i) a lipopolysaccharide of Burkholderia pseudomallei, (ii) a capsular polysaccharide of Burkholderia pseudomallei and (iii) a protein of Burkholderia pseudomallei or an immunogenic variant thereof or an immunogenic fragment of either of these, or a nucleic acid which expresses said protein, immunogenic variant or immunogenic fragment thereof in a host animal; for use in the prevention or treatment of infection by Burkholderia pseudomallei and/or Burkholderia mallei.

Abstract: A polypeptide derived from the periplasmic space of Yersinia pestis or a fragment or a variant of said polypeptide for use as a medicament is described. Pharmaceutical compositions comprising such polypeptides, such as OppA from Yersinia pestis, are also described and claimed. In a preferred embodiments the pharmaceutical composition further comprises existing protective antigens from Y. pestis such as F1 and V antigens. Such compositions are protective in mice and may be used as a vaccine for the prophylactic or therapeutic treatment of plague.