120 The Lymphocyte and Lymphocytic Tissue 



DIFFERENTIAL SUSCEPTIBILITY OF LYMPHOCYTES TO 

 HORMONE ACTION 



We have postulated for some years that maturation of immature lympho- 

 cytes occurs in part as a consequence of the continuous action of Cortisol on 

 these cells. The lymphocytic cytoplasm is reduced gradually, and eventually 

 the nucleus decreases in a fashion similar to that found in the erythroblastic 

 series. Finally, there is a complete loss of cytoplasm and nuclear integrity. 

 This gradual process is enhanced when larger than normal amounts of hor- 

 mone are available to act on the maturing lymphocytes. The overwhelming- 

 amount of evidence indicates that the effects of Cortisol described above on 

 lymphatic tissue are constant and physiologic. The results of hyperconcen- 

 tration appear to be exaggerated normal responses. 



REUTILIZATION OF NUCLEAR AND 

 CYTOPLASMIC MATERIAL 



When the histologic effects of adrenocortical hormones on lymphatic 

 tissue were first described, attention was called to the fact that changes 

 occurred in the reticuloendothelial cells as well as in lymphocytes. 6 The 

 point was made at that time that when lymphocytes are destroyed, they are 

 subsequently phagocytized by both fixed and free histiocytes (Figs. 9-4, 9-6, 

 9-7). 6 The fixed reticular stroma cells phagocytized both nuclear and cyto- 

 plasmic particles (Fig. 9-5). It was apparent, too, that the lymphocytes be- 

 come highly basophilic and resemble certain types of plasma cells. 6 - 19 The 

 suooestion was made that there was an ingestion and retention of reticular 

 cells of destroyed lymphocytes and that nuclear and cytoplasmic material 

 could be reutilized in formation of new cellular constituents during hetero- 

 plastic growth. This subject has been discussed in detail recently by White. 1 '" 



The possibility of reutilization of nucleic acid constituents and even non- 

 metabolized DNA and RNA by lymphocytes has recently been empha- 

 sized.- 1 -- It appears to be conclusive that at least a portion of nucleoprotein 

 from destroyed lymphocytes may be reincorporated in immature cells. 



The significance of this finding is enhanced in view of suggestions made 

 by numerous authors that lymphocytes are derived by heteroplasia from 

 reticuloendothelial cells. Therefore, the template for protein synthesis (par- 

 ticularly antibody protein) may be retained in the system of cells which 

 synthesize antibody. This concept is in line with our theory that antibody 

 synthesis starts in the most immature lymphocytes and continues to progress 

 as these cells differentiate. 15 Thus, when adrenocortical hormones destroy 

 mature lymphocytes, they release already formed antibody and also make 

 possible the phagocytosis of nuclear and cytoplasmic material by reticulo- 

 endothelial cells, and thus the process of differentiation may be renewed. 



