32 MASS. EXPERIMENT STATION BULLETIN 370 



(174 c) he reports that leukotic plasma inactivated by other oxidizing agents also 

 has the ability of inducing in chickens a certain degree of immunity against the 

 leukosis agent. 



Greppin (91) and Marchal, Paturel, Guerin, and Guerin (134, 135) reported 

 that the serum protein was below the normal level in birds affected with leukosis 

 and was higher than normal in chickens recovered and resistant to further in- 

 oculation. Schmitt (178) observed the serum proteins to be slightly decreased 

 in the well-developed disease, although the globulin fraction was relatively in- 

 creased which he believed to be the result of increased destruction of blood cells. 



Marchal, Paturel, Guerm, and Guerin (135) have indicated that the decrease 

 of serum protein in chickens with the active disease was ol the albumin fraction 

 and that the increase of serum protein in immune chickens was in the globulin 

 fraction with a normalievel of albumin. Chickens with either of two transmissible 

 sarcomas were found to have a decreased quantity of both albumin and globulin 

 in their blood serum (134). These conditions were not constant, as Marchal and 

 his coworkers (135) state that in ten instances animals with a normal or sub- 

 normal globulin value were resistant and, conversely, some with high globulin 

 values were susceptible to reinoculation. They concluded that the increase of 

 globulin did not support the immunity but that it was rather a result of the 

 increased resistance. 



Thomsen, Engelbreth-Holm, and Rothe Meyer (200) found complement- 

 fixing antibodies in the serum of about 20 percent of leukotic chickens. The 

 antigen used in the tests was a watery extract of either erythroblasts or myelo- 

 blasts from leukotic chickens. The antibodies were those directed against antigen 

 foreign to the inoculated chickens and contained in the blood cells or material 

 used to induce the disease rather than against the leukosis agent. Greppin (91) 

 carried out a small number of complement-fixation tests using as antigen either 

 an alcoholic extract of dried leukotic liver or an alcoholic extract of a leukotic 

 liver previously washed with acetone. The serums of four normal chickens were 

 negative as were those of 12 of 13 leukotic birds. 



Kabat and Furth (118 a) have reported on the use of crude tumor extracts, 

 leukotic plasma, and high-speed centrifugates, all containing the agent of either 

 Strain 1 or Strain 13 and supernatant fluid from the centrifugates as antigen. 

 Complement-fixation tests using serums of chickens with chronic sarcomas 

 produced by Strain 13 agent or from those resistant to repeated inoculation with 

 the agents of Strain 1 or 13 or high-speed centrifugate were uniformly negative. 

 Rabbit-antiserums against crude tumor extract, high-speed centrifugate and 

 supernatant fluid of sarcoma produced by Strain 13 agent, buffy coat of normal 

 chicken blood, and centrifugate of normal chicken spleen gave strong complement- 

 fixation reactions and cross reactions which indicated no antigenic difference 

 between the materials. Absorption tests with the complement-fixation reaction 

 and precipitin tests indicated that the bulk of material sedimented by high-speed 

 centrifugation from leukotic, sarcomatous, and normal tissues are of a similar 

 antigenic composition. 



Olson (155) attempted to demonstrate tissue sensitivity in ducks, geese, turkeys, 

 and chickens inoculated with material containing the agent of fowl leukosis. 

 The test materials, that is, leukotic bone marrow extract and a filtrate of leukotic 

 bone marrow, failed to elicit specific reactions when injected intradermally. 



