Feline vaccine compositions and method for preventing chlamydia infections or diseases using the same

A vaccine composition against feline Chlamydia psittaci infections comprising an immunogenically active component consisting of outer membrane antigens derived from inactivated feline Chlamydia psittaci in a dose of at least 50-1,000 ug/dose, an adjuvant, and a veterinary pharmaceutically acceptable carrier or diluent therefor, wherein said vaccine composition is purified of toxic immunogenic egg yolk sac substances, said vaccine composition prepared by the process comprising:

• (a) culturing the feline Chlamydia psittaci in egg yolk sac;
• (b) subculturing said egg yolk sac culture containing the feline Chlamydia psittaci in a suitable cell line to remove toxic immunogenic substances present in the egg yolk sac culture;
• (c) harvesting the feline Chlamydia psittaci from the contents of the subculture, said contents selected from the group consisting of infected cell line cells, subculture supernatant and a combination thereof;
• (d) inactivating the feline Chlamydia psittaci with inactivating agents;
• (e) extracting outer membrane antigens from the inactivated feline Chlamydia psittaci;
• and
• (f) mixing the inactivated feline Chlamydia psittaci with the adjuvant and physiologically acceptable carrier or diluent.