Abstract: The invention relates to a bacterial antigen library of Brucella suis surface antigens, its preparation and use. The library comprises 205 surface protein genes of Brucella suis constructed in an expression vector. The library can be used to prepare recombinant Brucella surface antigens. The expressed proteins derived from the gene library are important for the development of new vaccines to prevent brucellosis, or diagnostic kits to detect Brucellosis. The proteins prepared from the gene library can also be used to prepare a protein array to investigate pathogenic mechanism of brucellosis.

Abstract: The present invention provides vaccine compositions useful in prevention and treatment of Chlamydia sp. (e.g., C. trachomatis or C. pneumoniae) infection. Provided are polypeptide vaccine antigens comprising Chlamydia HtrA-derived sequences, including epitopic fragments, analogs, derivatives, and variants. Also provided are a method for inducing an immune response to a subject against Chlamydia infection, a method for preventing Chlamydia infection, or a method for treating a disease or symptom caused by or resulting from infection with Chlamydia, for instance, C. trachomatis or C. pneumoniae. In one embodiment, the present invention is drawn to C. trachomatis HtrA, which induces a cellular immune response and imparts partial protective immunity in vivo.