Antigenic and Skin-Reactive Properties of Fractions of Coxiella Burnetii

Summary Purified cell wall and protoplasmic fractions of Coxiella burnetii have been prepared after rupture of the intact organisms in a Mickle disintegrator. Water-soluble Phase I antigen was released from intact cells by treatment with trichloroacetic acid. These preparations were tested for their ability to protect guinea pigs against subsequent challenge with living organisms and to evoke dermal inflammatory responses upon intradermal injection into normal and sensitized rabbits. Cell walls possessed biologic activities similar to those of whole cells, but the protoplasm retained little of these activities. Although the trichloroacetic acid extract had a much higher content of Phase I antigen as determined by the complement fixation test than an equivalent weight of whole cells, the extract was about one-tenth as potent an immunogen as whole cells; it was also one-hundredth as active in producing skin reactions in sensitized rabbits as whole cells. It has not been determined whether the protective and skin-reactive properties are due to a single component of the cell wall or whether they are due to separate and distinct cell wall components.