26 G. LEJEUNE-LEDANT 



cause transplantation immunity be capable of absorbing those 

 haemagglutinins, in this way producing an inhibition of haemag- 

 glutination reactions? If this question could be cleared up, 

 haemagglutination inhibition would become a simple and rapid 

 test for the detection of any transplantation antigen. The 

 importance of such a test need hardly be emphasized. Indeed, the 

 present ways of identifying transplantation antigens consist in 

 biological techniques, such as induction of transplantation 

 tolerance (Billingham, Brent and Medawar, 1953), production of 

 transplantation immunity (Billingham, Brent and Medawar, 

 1956), or production of cutaneous hypersensitivity (Brent, Brown 

 and Medawar, 1958). Everybody knows, first, that the induction 

 of tolerance by cell-free extracts has not been very effective so 

 far, and secondly that the second-set response and the cutaneous 

 hypersensitivity reaction are time-consuming tests and, at least 

 as far as the last one is concerned, at the mercy of non-specific 

 influences (Medawar, 1959). 



The aim of the following group of experiments has been to 

 verify the presence or absence of haemagglutinins in mice after 

 administration of different types of transplantation antigens. 



A. Production of haemagglutinins after administration of 

 various transplantation antigens 



The mice used in this group of experiments are all of the lines 

 CBA and SA, the CBA used as donors, the SA as recipients. If the 

 H-2 antigenic combination in CBA mice is relatively well known, 

 we cannot say the same for the SA line. In our experimental 

 conditions, the normal survival time of a skin homograft from 

 CBA mice to SA mice is 10 • 5 ± o- 6 days. 



Preparation of transplantation antigens 



Living spleen cells, epidermal cells and cell-free extracts of 

 various kinds have been used. All the antigenic material is injected 

 by the intraperitoneal route, except for the epidermal cells. 



