MOTHER-FOETUS IMMUNOLOGICAL RELATION- 

 SHIP AS AN EXCEPTIONAL HOMOGRAFT MODEL 



M. Hasek, V. Haskova, A. Lengerova and M. Vojtiskova 



Department of Experimental Biology and Genetics, Institute of Biology, Czechoslovak 

 Academy of Sciences, Prague 



The genetic structure of the mammalian foetus developing 

 within the mother is different from that of the mother's tissues 

 (with the exception of intra-inbred mating). The foetal part of 

 the placenta and the foetus itself could therefore be regarded as a 

 homograft. Under normal conditions, however, the mother is 

 not immunized by the tissue antigens of the foetus. Even repeated 

 pregnancy does not lead to transplantation immunity, and females 

 preimmunized against the tissue antigens of the breeding male can 

 have normal offspring (Heslop, Krohn and Sparrow, 1954; 

 Medawar and Sparrow, 1956). 



Three possible explanations of the absence of a homotrans- 

 plantation reaction between mother and foetus have mainly been 

 considered: (i) antigenic immaturity of the foetus; (2) non- 

 specifically decreased reactivity of the pregnant female; (3) the 

 anatomical barrier between mother and foetus. 



(i) The first possibility is, however, contradicted by results 

 demonstrating the antigenic maturity of the foetus. In the 

 pioneer studies on tumour immunity, foetal tissue has been used 

 many times for successful immunization against homografts of 

 tumours. Immunity induced by injections of foetal tissue has also 

 been demonstrated by a subsequent skin transplantation test 

 (Billingham, Brent and Medawar, 1956; Woodruff, 1958; 

 Chutna and Haskova, 1959). As far as transplantation antigens are 

 concerned, basic evidence of a complete, antigenic maturity of the 



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