A method of culturing lawsonia intracellularis bacteria

Abstract

The invention pertains to a method of culturing Lawsonia intracellularis bacteria, the method comprising a) infecting a first portion of McCoy cells with Lawsonia intracellularis bacteria, b) growing the first portion of infected McCoy cells in a first growth medium at a dissolved oxygen concentration less than 18% to arrive at a first culture of McCoy cells infected with Lawsonia intracellularis bacteria, c) determining the concentration of pyroptotic McCoy cells in the first culture of McCoy cells, d) combining a second portion of the first culture of McCoy cells with a second growth medium, and passing a third portion of the first culture to a third growth medium containing fresh McCoy cells, such that the third growth medium is inoculated with 0.01-0.25 pyroptotic McCoy cells per fresh McCoy cell, e) growing the McCoy cells in the second growth medium at a dissolved oxygen concentration less than 18% and growing the McCoy cells in the third growth medium at a dissolved oxygen concentration less than 18% to arrive respectively at a second culture of McCoy cells infected with Lawsonia intracellularis bacteria and a third culture of McCoy cells infected with Lawsonia intracellularis bacteria, f) harvesting the McCoy cells infected with Lawsonia intracellularis bacteria from the second culture of McCoy cells and determining the concentration of pyroptotic McCoy cells in the third culture, and g) performing steps d)-f) for the third culture, wherein the third culture serves as the first culture of McCoy cells.

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