STUDIES ON TRANSPLANTATION ANTIGENS 

 L. Brent, P. B. Medawar and M. Ruszkiewicz 



Department of Zoology, University College, London 



Our work on transplantation antigens during the past two 

 years has consisted of (i) an attempt to correlate the sensitizing 

 power of antigens with their power to excite the formation of 

 humoral antibodies in vivo or to inhibit their action in vitro; and 

 (2) further investigations of the physical and chemical properties 

 of cellular extracts containing antigenic matter. 



The principle underlying the correlation referred to under 

 heading (i) is straightforward. A graft transplanted from (for 

 example) an A-strain donor to a CBA or C3H recipient has two 

 distinguishable effects : it sensitizes its recipient, in the sense that a 

 second graft from an A-strain donor will be destroyed more 

 quickly than its forerunner; and it immunizes its recipient in the 

 more conventional sense of provoking the formation of humoral 

 antibodies. The isoantigens responsible for these two reactions 

 have a common genetic determination, and the temptation is 

 therefore to believe either that they are identical, or — as Snell 

 (1957) has suggested — that they have similar determinant groups 

 and differ only in respect of subsidiary attachments which affect 

 the modality of the immune response. If either of these inter- 

 pretations is true, then antigenic matter known to sensitize should 

 also absorb (or, in soluble form, should inhibit the action of) the 

 corresponding humoral antibodies. 



The experiments of Hildemann and Medawar (1959) failed to 

 uphold this interpretation. Their failure must be attributed to the 

 inaccessibility of determinant sites in the very crude antigenic 



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