TRANSMISSIBLE FOWL LEUKOSIS 21 



Autonomous growth of the leukemic cells in granuloblastic leukosis was dem- 

 onstrated by Crank and Furth (26). They transfused 15 chickens with 15 to 

 v30 cc. of leukemic blood obtained from a bird affected with the granuloblastic 

 form of the disease. The result was that nine birds died within two to three and 

 a half davs after inoculation. The count of white blood cells in these chickens 

 increased greatly during this relatively short time. Many of the transfused cells 

 were removed from the circulation in the capillary bed of the spleen, liver, and 

 lung. Earlier work (Crank and Furth 27) had indicated that the retained cells 

 multiplied in these sites by autonomous growth in the susceptible birds and that 

 in resistant fowls they were disposed of by the phagocytes of the organ involved. 



As a result of experiments in which chickens received intravenous injections 

 of India ink to blockade the reticulo-endothelial system previous to inoculation 

 with leukosis material, Jarmai, Stenszky, and Farkas (105) came to the conclusion 

 that the leukosis cells are not descendants of the reticulo-endothelial system. 

 The circulating leukotic cells were free of ink particles even though the livers and 

 spleens of these birds were entirely black with the ink. 



Storti and De Filippi (185) could find no evidence of participation of the 

 phagocytic elements of the reticulo-endothelial system in the formation of the 

 extramedullary myelopoietic foci in leukotic fowls. Their experiments were 

 carried out in chickens in which leukosis was produced by the Oberling and Guerin 

 Strain of the leukosis agent. The birds received intravenous injections of India 

 ink to mark the phagocytic cells and were killed at various stages of the disease. 

 Storti and De Filippi came to the conclusion that the foci of leukotic cells in 

 tissues other than the bone marrow represented local proliferation of cells orig- 

 inally derived from the marrow. 



Engelbreth-Holm (51) found that the nuclei of the primitive erythroblastic 

 cells from the bone marrow of leukotic chickens have a significantly greater 

 average diameter than the nuclei of comparable normal cells, which feature he 

 believes indicates the neoplastic character of the leukotic cells. 



Magat and Magat (132) have noted a characteristic absorption in the spectrum 

 of leukemic blood from chickens which had received an intravenous injection of a 

 colloidal lecithin and perhydrite mixture. This absorption of the spectrum of 

 blood was not noted after injection of the complex into normal birds or birds 

 affected with avian pest, diphtheria, or acute anemia. There was an increased 

 coagulability of the blood following administration of the material which was 

 brought about by smaller doses in leukotic fowls. Magat and Magat concluded 

 that their experiments showed a disturbance of the physio-chemical properties 

 of the blood in leukosis. 



The various reactions produced by the different strains of agents causing 

 transmissible fowl leukosis may be regarded as an indication of selective action on 

 different developmental levels of descendants from a common mesenchymal cell 

 (Engelbreth-Holm and Rothe Meyer, 58). Thus they suggest that the so-called 

 complex strains (Strain E-S of these workers and the leukosis-sarcoma strain of 

 Oberling and Guerin) attack a cell derived from the mesenchyme which has 

 the potentiality of forming either blood cells or connective tissue. The complex 

 strains 2 and 13 of Furth may also belong to this group. Further, they believe 

 that the agents producing both erythroblastic and granuloblastic leukosis act 

 upon a stem tell common to both and that the agent giving rise to pure leukosis 

 stimulates a cell already differentiated to the extent that it can form only cells 

 of the erythrocytic or granulocytic lineage. They carry on with their hypothesis 

 and suggest that the agent giving rise to the Murray-Begg endothelioma acts 

 upon a cell of the angioblastic series of this group and the agents of the Rous 



