Morphological changes in the lymphatic glands and spleen of guinea pigs repeatedly inoculated with Rickettsia burneti (the morphology of immunity)

Summary

Superinfection, induced in guinea pigs with a large dose of R.burneti, was accompanied by a brief rise of the complement fixing antibody titer (on the 6th–12th day) and a subsequent drop (on the 12th–50th day) and a new rise (on the 60th day). Morphological changes in the lymph nodes and spleen were characterized by a turbulent but brief proliferation of reticulum cells for a period of 2–4 days with subsequent rapid transformation of most of them into plasma cells. In this way it seemed as if the stocks of reticulum cells, capable of such transformation, were expended. The quick and almost simultaneous maturation of plasma cells leads to their rapid disappearance by degeneration. Temporary atrophy of reticular tissue especially noticeable in the medullary zone of the lymph nodes, resulted. The author considers that this temporary atrophy is connected with the state of immunological depression. The latter evidently results from the inhibition of the processes involved in the formation of reticulum cells, capable of transformation into antibody-producing cells, i. e., into plasma cells.