Origin of Bone Marrow Plasma Cell Associated with Allergic and Immune States in the Rabbit. ∗

The observation of a plasmacytosis of the bone marrow of a man with a fatal endocarditis, coupled with Downey's description of a great number of plasma cells in the bone marrow of a rabbit with an incidental, non-specific, subcutaneous abscess suggested an experimental method for increasing the bone marrow plasma cell content. This reaction was also indicated by the bone marrow from rabbits allergic to and immunized against Streptococcus viridans, obtained through the courtesy of Dr. B. J. Clawson of the Department of Pathology, University of Minnesota. In these animals it was noted that the allergic and immune animals showed a more extensive medullary plasmacytosis than those that were immune but not allergic. Through the study of the myeloid tissue during the development of a plasmacytophilia, we felt something of the origin and function of the bone marrow plasma cell might be determined.

There are many conflicting theories regarding the origin of the myeloid plasma cell (Downey, 1 Michels, 2 Rohr, 3 Jordan and Morton, 4 and Osgood and Ashworth 5 ). The current theories make the lymphocyte, histiocyte, fibroblast, myeloblast, erythroblast, plasmacytic reticulum cell and specific plasmablast the parent of the bone marrow plasma cell.

The procedure we employed was as follows: Obtain a control sample of normal marrow; induce an increase in the plasma cells and follow the bone marrow picture by means of successive biopsies while the increment in plasma cells is in progress. In this manner, we were able to identify the progenitor of these cells during their initial stage of differentiation in the bone marrow.

We treated a series of 13 rabbits by Clawson's method, i. e., giving a subcutaneous injection of Streptococcus viridans broth agar mixture and thus making the animal allergic to this antigen.