Discussion 155 



(nucleated viable) homologous cells than isologous cells to obtain the 

 same therapeutic result. We wanted to know whether the regenerated 

 bone marrow of irradiated C57 Bl. mice, that had been treated with 

 CBA bone marrow cells, consisted of CBA cells or of C57 Bl. cells. The 

 question could be answered by injecting this bone marrow into both 



CBA cells 



i 



irradiated C57 Bl. 

 U d. 



cells 



/ \ 



'^ irradiated '^ 

 CBA C57BI 



effect: -f- 



Fig. 2. (Van Bekkum). 



irradiated CBA and C57 Bl. mice and by comparing the therapeutic 

 effects in the two strains (Fig. 2). The results of this experiment 

 (Table II) strongly suggest that the bone marrow tested consisted 

 predominantly of CBA cells. 



Table II (Van Bekkum) 

 Therapeutic Effect of Regenerated Bone Marrow 



Number of % survivals at 32 days 



cells X 105 CBA C57BI 



10 



2 30 . 



4 100 



8 90 



The second method employed specific antisera, which permitted the 

 identification of rat and mouse erythrocytes. In this case lethally 

 irradiated CBA mice were injected with rat (WAG) bone marrow cells 

 and agglutination reactions were carried out with both antisera in 

 samples of the peripheral blood of the survivals. Fig. 3 shows that from 

 the tenth day after irradiation onward a gradual replacement of the 



