AN ISOANTIGENIC LIPOPROTEIN 85 



diary attachments to a substance of genetically determined specifi- 

 city may influence the occurrence and nature of the immuno- 

 logical response incited in vivo (Snell, 1957; Kandutsch, 1961). 

 The relationships of antigen structure to the kind of immuno- 

 logical response obtainable, along with investigations into the 

 chemistry of genetically determined alterations in the antigens and 

 the roles of these substances in cell membranes, may be fertile 

 fields for further research. 



Summary 



A Triton-soluble lipoprotein isolated from a particulate fraction 

 of sarcoma I appeared to be homogeneous in moving boundary 

 and zone electrophoretic studies. It was isoantigenic, as measured 

 by the enhancement test or by its ability to induce the formation 

 of red blood cell agglutinins, and was active in a haemagglutina- 

 tion inhibition assay. The Triton-soluble lipoprotein was de- 

 graded to a more water-soluble form by digestion with snake 

 venom. The altered substance, recovered by acid precipitation, 

 contained two electrophoretically separable components — one 

 in small amount. The altered material retained the ability to 

 inhibit red blood cell agglutination by specific antibody. 



Some of the chemical and physical properties of the Triton- 

 soluble lipoprotein and of the material recovered after digestion 

 with snake venom are described. 



Acknowledgement 



We are grateful to Dr. Eugene Roberts for suggesting that the effects of snake 

 venom be examined and for a supply of the venom. 



REFERENCES 



Day, E. D., Kaliss, N., Aronsen, A. I., Bryant, B. F., Friendly, D., 

 Gabrielson, F. C, and Smith, P. M. (1954). J. nat. Cancer Inst., 15, 145. 



GuRD, F. N. (i960). In Lipid Chemistry, p. 275, ed. by Hanahan, D.J. New 

 York: Wiley. 



