102 The Lymphocyte and Lymphocytic Tissue 



tion both of normal and malignant tissue. Gallone, Radici, and Riquire 

 examined lymph nodes draining sites of skin homografting and fonnd many 

 large lymphoid cells with granules which stained with pyronine. 12 In a more 

 extensive study Scothorne and McGregor studied lymph nodes of rabbits 

 regional to skin autografts and homografts in the ears of rabbits. On the 

 second day following homografting, the draining lymph nodes showed some 

 enlargement of the medullary cords and some increase in mature plasma cells 

 in these cords. The major changes began on the fourth day, when accumula- 

 tions of large lymphoid cells were found in the greatly enlarged cortex of the 

 node, with similar changes of smaller degree in the medulla. These cells 

 contained pyroninophilic granules, but almost all this character of these 

 cells was lost soon after graft destruction began. In the medulla the cords 

 showed an increased number of mature plasma cells, and the sinuses con- 

 tained many small lymphocytes as well as large lymphoid cells. These changes 

 were not observed in lymph nodes contralateral to the homografted ear or 

 in lymph nodes draining the site of autografts. VA In a subsequent study Scot- 

 horne treated skin-homografted rabbits with cortisone. The graft was re- 

 tained and was apparently healthy up to the end of the experimental period 

 (1() days), and the large-lymphoid-cell response in the draining lymph nodes 

 was entirely absent. 14 



Lymph nodes draining sites of implantation of tumors have also been 

 examined. Ellis, Toolan, and Kidd implanted C :i H mouse mammary carcino- 

 mas and lymphosarcomas in a resistant strain of mice and then studied the 

 regional lymph nodes. 1 " 1 A few days after the implantation, the draining 

 lymph node had become markedly hyperplastic, with an increase in the 

 size and number of germinal centers and with thickening of medullary cords. 

 In the latter there was proliferation of elements that seemed to be young 

 plasma cells. 



LYMPH NODE CELL TRANSFER IN RELATION TO THE 

 IMMUNOLOGY OF TISSUE TRANSPLANTATION 



In the early studies of tissue reactions at the site of homografts, various 

 workers had concluded that the infiltrating cells were involved in a local 

 defense of the host tissues against the transplant, although it was not known 

 what the mechanism of this defense might be. Later, histologic studies of 

 lymph nodes regional to transplanted tissue had indicated substantial hyper- 

 plasia in these nodes of lymphoid cells — cells of the lymphocytic and plasma- 

 cytic series. These changes were so similar to histologic observations which 

 had been made in lymph nodes draining sites of injection of known antigens, 

 such as those of bacterial, cellular, or viral origin, as to suggest that here, 

 too, the lymphatic hyperplasia indicated a reaction to antigenic material in 

 the transplanted tissue. 



