ATTENUATED STRAIN, PROCESS FOR PRODUCING AN ATTENUATED STRAIN, VACCINE FOR INDUCING AN IMMUNE RESPONSE TO LAWSONIA INTRACELLULARIS BACTERIA

摘要

The invention relates to an attenuated strain to a process for preparing the same and to a vaccine for preparing the same and to a vaccine for inducing an immune response to Lawsonia intracellularis bacteria. The strain is N343NP40 WK, having the deposit number ATCC 55783, and belongs to Lawsonia intracellularis species, it has curved cells and it is a gramm-negative bacteria. The process for producing the strain consists in obtaining a culture of cells infected at an oxygen concentration of 18 %, agitating said infected cells so as to cultivate bacteria while maintaining said infected cells in suspension, passaging at least a portion of said cultivated bacteria and selecting an attenuated strain in order to provide an attenuated Lawsonia intracellularis bacteria. According to the invention, the vaccine comprises an effective amount of the defined strain N343NP40WK and a pharmaceutically acceptable carrier.